Take off with snow on wing

[Jazz Hands]

due to the intense cold (minus 20) the snow hadn't adhered to the wings and that they were completely clean underneath

Quite possibly the exact same circumstances at in the original video.



It's been confirmed to me - by the Met Office and METAR archives - that the temperature at Moscow on 1 Jan varied between -1C and zero C.

That's not "intense cold"...

[Skyerr]

WET SNOW : is a condition where, if compacted by hand, snow will stick together and tend to form a snowball. Its density is approximately 0.4 kg/l
(3.35 lb/US Gal).
DRY SNOW : is a condition where snow can be blown if loose, or if compacted by hand, will fall apart again upon release. Its density is approximately 0.2 kg/l
(1.7 lb/US Gal).
COMPACTED SNOW: is a condition where snow has been compressed (a typical friction coefficient is 0.2).

A318/A319/A320/A321 PER-TOF-CTA-20 P 1/2

[DOVES]

Dear Sirs
With reference to the incident:
ASN Aircraft accident McDonnell Douglas MD-81 OY-KHO Gottrra (http://aviation-safety.net/database/record.php?id=19911227-0)
First of all let me say: "Chapeau" to the exceptional skill of the innocent crew who brought the airplane on ground with 0 kill.
Let me add that after that accident some woolen threads were installed at the roots of the wings of the MD80, free to shake into the wind, in order to facilitate the identification of subtle icing Vetrone by the crew, often unnoticed.

[lomapaseo]

Let me add that after that accident some woolen threads were installed at the roots of the wings of the MD80, free to shake into the wind, in order to facilitate the identification of subtle icing Vetrone by the crew, often unnoticed.


Mostly correct :ok: but they were not put there to depend on the wind for visualization. They required movement by a pole device held by a man on a ladder. If you couldn't move them they were probably covered by a film of ice.

The biggest problem with the dispatch with wing ice was the first flight of the day after an overnight in drizzle/snow. The snow would be blown off on the ground but they missed the check underneath for ice.

Contrary to popular belief there were only a few incidents of ice due to cold soaked fuel in above freezing conditions.

[Cagedh]

Not to mention it looks like he is cruising at FL 650 or thereabouts.
The horizon looks unduly curved

http://i1261.photobucket.com/albums/ii582/Cagedh/Snowpichorizon.jpg

Doesn't the picture look more familiar if you take away the camera tilt? Looks genuine to me.

[Skyerr]

Thank you, I have known now

[AirRabbit]

The more "well known" Air Florida flight 90, a 737 which crashed into the Potomac river was more an issue of incorrectly set engine thrust (due icing of the P2T2 engine sensors) than ice on the wing.
The accident you cite was not due to incorrectly set engine thrust. I have little doubt that the PT2 probes were blocked; I also believe that this resulted in erroneous EPR readings in the cockpit. The flight crew set the takeoff EPR at the computed 2.04 setting and that, because of the PT2 error, only achieved approximately 75 percent of the available takeoff power. Undoubtedly, this increased the ground roll. But the point that goes unmentioned in this discussion is that the airplane was certificated to be able to accelerate to decision speed, or V1, (albeit with both engines operating), experience the complete failure of one engine, and be able to continue the takeoff safely. Again, I acknowledge that the takeoff roll would have been longer; however, once the computed V1 speed was reached, the accident airplane had 50 percent more power than was required for certification. I submit that regardless of how much time or distance was involved in getting the airplane to the V1 speed, once there, if it had one engine operating at full power, it should have flown as it was certificated to do. It had 2 engines operating at 75 percent power. Not only did this provide 50 percent more power than necessary, it was provided in a symmetrical manner. Yet the airplane failed to fly. Why would that be?

The point is that the accident was actually caused by something other than a low power setting. However, because this is a 30-year old accident, there may be little interest in learning more about it - so I'll refrain until I know that there might be some interest. If you are interested in knowing what this additional information would be, I’d be glad to provide you with some facts that, while they were available at the time, were not given the attention they deserved. As a result, there was a large amount of misinformation being disseminated and the folks who took the vast majority of the “blame” were no longer around to offer their defense.

And ... just for accuracy in regulatory requirements ... with regard to operations in ice or snow, and the YouTube clip that lead off this thread ... the rules say the following...
No pilot may take off an airplane that has frost, ice, or snow adhering to any propeller, windshield, stabilizing or control surface; to a powerplant installation; or to an airspeed, altimeter, rate of climb, or flight attitude instrument system or wing, except that takeoffs may be made with frost under the wing in the area of the fuel tanks if authorized by the FAA.
One should note the operative wording in the requirement ... adhering to ...

[Basil]

One should note the operative wording in the requirement ... adhering to ...
May I infer that you are not suggesting that it is OK to depart with dry snow lying on top of the wing of a jet transport aircraft?

[reracked]

Air Rabbit, I may be missing something here, but I don't think the calculations are "calculated" on a 1 engine take -off from start of take off roll ? so they had a lot less thrust than was calculated for (as they had 75% of normal) up to V1, given that V1 happened at ? ? distance compared to calculated, Vr was also at some indeterminate point. . . nonetheless, I think, whatever deposits they had on the wings (even on an "old" 200/Classic wing) are unlikely to have been helpful.
I think, the whole point of this thread, is to determine whether TO with the deposits we see in the Video is


A- Criminally irresponsible or
B - "No problem" (airBaltic FO's will understand that sarcasm)

Well, you decide :hmm:

[9.G]

highly irresponsible from a gentleman point of view to make a lady worrying bout the snow on the wing. Jeez spray it clean and make them smile and I'm sure they'll be more approachable during next layover. Besides, as far as I know, pretty much all airlines pay for block time. Go figure, what's the rush line up in a queue for deice, have a coffee and a friendly chat with a lady and off you go with few extra bucks. It's safe, relaxed and maybe even far-reaching deicing catching up with the future Mrs. Brilliant opportunity to engage in social intercourse with the ladies. Can't wait for the next winter ops.

[Nieuport28]

[/QUOTE]highly irresponsible from a gentleman point of view to make a lady worrying bout the snow on the wing. Jeez spray it clean and make them smile and I'm sure they'll be more approachable during next layover. Besides, as far as I know, pretty much all airlines pay for block time. Go figure, what's the rush line up in a queue for deice, have a coffee and a friendly chat with a lady and off you go with few extra bucks. It's safe, relaxed and maybe even far-reaching deicing catching up with the future Mrs. Brilliant opportunity to engage in social intercourse with the ladies. Can't wait for the next winter ops.[QUOTE]


More Approachable? No question. :ok:

[BobM2]

The point is that the accident was actually caused by something other than a low power setting. However, because this is a 30-year old accident, there may be little interest in learning more about it - so I'll refrain until I know that there might be some interest. If you are interested in knowing what this additional information would be, I’d be glad to provide you with some facts that, while they were available at the time, were not given the attention they deserved....

OK AirRabbit, I'll bite. What did cause AF to go for a swim?

[CaptainProp]

From the NTSB report of the Air Florida crash states: (still relevant, 30 years later!!)

The National Transportation Safety Board determines that the probable cause of this accident was the flight crew’s failure to use engine anti-ice during ground operation and takeoff, their decision to take off with snow/ice on the airfoil surfaces of the aircraft, and the captain’s failure to reject the takeoff during the early stage when his attention was called to anomalous engine instrument readings. Contributing to the accident were the prolonged ground delay between deicing and the receipt of ATC takeoff clearance during which the airplane was exposed to continual precipitation, the known inherent pitchup characteristics of the B-737 aircraft when the leading edge is contaminated with even small amounts of snow or ice, and the limited experience of the flightcrew in winter operations./

So...

their decision to take off with snow/ice on the airfoil surfaces of the aircraft

....and then....

the prolonged ground delay between deicing and the receipt of ATC takeoff clearance during which the airplane was exposed to continual precipitation

The de-icing at the gate was completed 15:10, the aircraft finally took off at 15:59:46 after taxi out and waiting in turn for T/O in snow reported as alternating between "moderate" and "heavy".

@ 15:47, about 12 min before take off the First Officer made the following comment in reference to his (right) wing:

this one’s got about a quarter to half an inch on it all the way

The report then goes on stating:

...the V2 callout occurred at 1600:37 and the sound of the stall warning (stickshaker) began 2 seconds later and continued until impact.

Nothing much to say really.....

I read the report years ago but went back and read it again. I can really recommend to all of you to read it as it highlights a lot of potential issues with operating in winter conditions.

[Keylime]

Wimps......looks like a little bit of hoar frost.....

Big Balls Airlines Funny Video Clip - Airplanes (http://www.funnyearth.com/html/videos/Big_Balls_Airlines.php)

[BobM2]

From the NTSB report of the Air Florida crash states: (still relevant, 30 years later!!)

Sure, I've read the report. But, AirRabbit seems to have something more to add. Just trying to get him to respond.

[CaptainProp]

Ok, yea could be that he was implying that he had more to add.

I thought he meant the snow / ice contamination of the aircraft airfoils in addition to the more know EPR issue they had due to ice and that's why I posted.

[Max Angle]

De-icing could easily wipe the profit (or increase the loss!) from a short-haul flight and perhaps a long haul as well but you need to look at a route over the course of a year. Any sensible operator will factor in the total costs over a year which if its a route that requires a lot of de-icing in winter will be considerably higher than one that doesn't.

[Scylla]

OK - deice fluid currently in the order of £2 per litre in the UK and takes around 1500lts to deice a mini-'Bus. But it's still cheaper than crashing (and my lot are quite happy to budget for this in their accounts - the fluid, not the crashing)

[AirRabbit]

Please understand that my motive in saying what I’m saying (and what I’ve said previously), is in no way intending to impugn the fine reputation or the integrity of the NTSB or of the dedicated and professional employees at the Safety Board. My only motive has been a continuing effort to describe the actions of the flight crew from a slightly different perspective while providing what I believe to be clarifying information regarding the cause of the accident and, to the best I am able, set the record straight– as much as one can this long after the fact.

I should also say, up front, that I, too, continue to have questions for which I still do not have answers. There is not a winter flying season that comes and goes that I do not wish that the flight crew of that Air Florida flight had been more inquisitive about the condition of the wings. Perhaps if one of them had taken a few moments to observe the wing surfaces on a walk back through the cabin at some point prior to the takeoff, he would have noticed something … anything … that would have triggered a different course of action. But that didn’t happen. So, what I’m left with is what happened … the results of the investigation … and a long-time consideration of what that investigation revealed to me. For simplicity, I would like to address some issues I believe are important, and I’ll do that in chronological order, beginning with the airplane de-icing.

The De-icing. The NTSB Aircraft Accident Report described an “analysis of the deicer vehicle found that a nonstandard nozzle had been used” and was dispensing deicer fluid with a mixture different from what was expected. The accident report states “the mixture dispensed differed substantially from the mixture selected…” such that the “deicing fluid in solution was about 18 percent rather than 30 percent.” The report further states that the right side of the aircraft was “deiced with 100 percent water and a final overspray applied with a 20 to 30 percent deicer to water solution selected.” The “20 to 30 percent” mixture for the overspray was the selected value, not the mixture that was actually applied. Standard deicing procedures called for deicing and overspray to be conducted with 30 to 40 percent solution of glycol in heated water. What the report does not contain is that the nonstandard nozzle dispensing fluid at 18 percent glycol mixture was a reasonably accurate measurement for the minimal flow of fluid from the deicing wand at a nominal, or minimal, flow rate. However, when the operator increased the flow rate, all of the additional volume flow came from the heated water tank, and none from the glycol tank – effectively lowering the solution percentage by an unknown but substantial proportion. From my perspective, deicing over half of the airplane and the wing surfaces with 100 percent hot water and over-spraying the entire aircraft with a maximum concentration of 18 percent glycol (and very probably significantly less depending on the volume flow at any given point in the overspray process) cannot simply be catalogued and filed away. I believe this to be the pivotally significant action in the series of actions leading up to the accident and was, singularly, the accident cause.

The Takeoff Clearance and the Absence of an Aborted Takeoff. The accident report goes into some detail about the lack of assertiveness on the part of the F/O and the lack of receptiveness on the part of the Captain during the initial stages of the takeoff roll when the F/O apparently noted some engine indication anomalies. Many have quoted from the CVR transcript indicating that during the takeoff roll there were a number of times the F/O questioned the accuracy of the engine instruments. My question is how do the readers of the transcript know that the F/O was referencing the engine instruments? If it was an “anomaly” with the engine instrument readings, the logical question that the casual observer would make is “why didn’t they simply abort the takeoff?” In fact, the accident report cites 3 factors as the probable cause of the accident, with the third one being “the captain’s failure to reject the takeoff during the early stages when his attention was called to anomalous engine instrument readings.” The report also states that the investigation “considered the possibility that the captain was aware of and concerned about the decreasing separation between his aircraft and the aircraft landing behind him.” However, the report concludes that this decreasing separation “would likely have become a factor only after the landing aircraft reported ‘over the lights.’” I’d like to look at that conclusion for just a moment.

Pilots sit at the arrival ends of runways multiple times each day – day in and day out. They watch arrival after arrival – big airplanes, little airplanes, fast airplanes, and airplanes not so fast. What they do is get a “feel” for the timing involved. I know of no pilot who has ever taxied into position on an active runway, knowing there is an airplane on final, who has not had at least a slight “tingle” down the back of his or her neck. That tingle grows until takeoff clearance is received, the throttles are pushed forward, the airplane accelerates, and the crew rotates into the air. Then, and only then, does the tingle subside. The investigators concluded that the Captain would not have considered the approaching airplane to be worrisome until that crew reported “over the lights.” I respectfully disagree with that conclusion; and I know of few, if any pilots who would accept that conclusion. Would you?

The traffic that was referred to was Eastern flight 1451, a B-727. I know that the final approach speed is dependent on several factors (weight, flap setting, etc.), but because the tower operator asked the Eastern crew to fly “reduced speed,” I’ll use a speed of 130 knots. With a head wind of approximately 10 knots, the ground speed would have been approximately 120 knots, or 138 miles per hour. At that speed it would take the airplane approximately 64 seconds to cover the “two and a half miles,” or the 13,200 feet, reported by the tower operator. From that time of that report (59:28) until the F/O took control of the throttles (59:46), 18 seconds had passed. It was 16 seconds later (00:02) when the F/O first indicated that there was something that he questioned. This was now 34 seconds after the tower’s notification that landing traffic was “…two and a half out for the runway.” When the Captain called “80-knots” (00:09), the airplane had probably reached a position 1000 to 1500 feet down the runway. The investigators believed that the F/O was concerned about engine “anomalies,” but I believe he was confused about physical throttle position being different from what he had become used to recognizing. He was used to having his arm and his hand at a position that “felt familiar” (i.e., muscle memory), but when the instruments told him that the proper position had been reached, he recognized “something” different but didn’t recognize that his arm and hand were in a slightly different position – and this is what was confusing for him. I believe that it is quite likely that both crewmembers were attempting to identify anything out of the ordinary – but I contend that the engine instruments were reading what the crew expected them to read – and it is only after-the-fact that we’ve learned that the PT2 probes being blocked would have allowed the EPR gauges to indicate the desired setting for takeoff with the engine thrust actually set to a lower value. The other engine instruments were likely close to what should have been “normal” but, and I think significantly, those indications were steady and symmetrical. The flaps were properly set. The speed brakes were stowed. Everything that either crew member could see seemed normal.

The investigators believe that once the F/O voiced those concerns the Captain should have aborted the takeoff. Before agreeing or disagreeing with that belief, I think the significant question should be … where was the B-727 at this time? Assuming the airspeed of the B-727 was 120 knots and that this speed remained constant, and that its position was accurately relayed by the controller to the departing flight crew, at this 34 second mark, mathematics tells us that the B-727 would have been approximately 6300 feet from the threshold. That’s well over a mile out … but, that is ONLY if the assumptions are correct. To some – perhaps to many – that distance may seem to be adequate spacing for the departing airplane to abort with little or no problem. However, the fact is that a scant 2 seconds after the B-737 reached 80 knots (which happened at 00:09) the B-727 crew reported “cleared to land, over the lights” (which happened at 00:11) The approach lighting system extends 2,400 feet from the threshold. If the B-727 was indeed “over the lights” as they, themselves reported, they were something less than 2,400 feet from the threshold – still maintaining that constant 120 knots. Either they were flying a lot faster than my assumption or the tower operator provided inaccurate information to the departing crew. At that point, the B-737 was probably less than 2000 feet down the runway. Again, estimates vary, but there are some who believe that the B-727 actually landed prior to the B-737 lifting off … meaning that both aircraft were on the runway at the same time! Had the B-737 crew aborted, I believe there is at least a reasonable possibility that two aircraft would have been involved in an accident on the runway, and the probability of that accident occurring goes up dramatically, second by second.

I probably should point out that the both the aircraft immediately preceding the accident B-737, “Apple 58” (a New York Air DC-9) and the aircraft immediately following the accident B-737, “Six Eight Golf” were both in the takeoff que for approximately the same amount of time and both aircraft took off from the same runway and departed without incident.

The Airplane Performance During the Takeoff. It would come as no surprise to anyone that a lower engine power setting would result in a longer than normal takeoff roll given that all other parameters were the same. In this case, as I’ve said previously, I have little doubt that the accident airplane PT2 probes were blocked – most likely blocked with ice. I also believe that this resulted in erroneous EPR readings in the cockpit. I believe that the flight crew set the takeoff EPR at 2.04 and that, because of the blocked PT2 probes, the actual engine thrust was set to approximately 75% of maximum. Undoubtedly, this increased the ground roll. But the point that goes unmentioned in this discussion is that the airplane was certificated to be able to accelerate to decision speed, or V1, (and I recognize that airplane certification is based on all engines operating at full power up to that V1 speed), experience the complete failure of one engine, and be able to continue the takeoff safely. What happened in this case was that the airplane accelerated down the runway with both engines producing approximately 75% power. Again, I acknowledge that the takeoff roll would be longer to get to this point. However, once the computed V1 speed was reached, regardless of how long it took to get there (downhill roll, rubber-band, whatever…), from that, “V1” point forward, the airplane should have been able to fly on one engine at 100% power. From the CVR transcripts we know that the V1, Vr, and V2 speeds were noted to be “thirty eight, forty, forty four” – meaning 138, 140, and 144 knots, respectively. In fact, after reaching “V1” (and we know this speed was reached, as the Captain’s “Vee One” call-out is noted on the transcript) this airplane had 2 engines operating at 75% power, which is clearly 50 percent more power than should have been required – and as an added benefit the power that was being produced was produced symmetrically. We also see on the CVR transcript that in addition to the “V1” speed being reached, we know that “V2” speed was also reached, and was also confirmed by the Captain’s callouts. We should also recall that V2 is generally 20% above the stall speed for that aircraft weight and configuration. Yet after having reached a speed of more than V2 (actually 150 knots), as confirmed by the Flight Data Recorder (FDR) tracings, with symmetrical power of two engines, each producing 75 of maximum power, the airplane failed to fly. Why?

Many people instantly respond with the assumption that the airplane had added weight due to the accretion of ice. Today we know that if an airplane the size of a B-727 is completely covered in ice, the total weight of that ice is something on the order 180 to 350 pounds – somewhere between 1 and 2 additional passengers. So, if there was additional weight of ice, that small increase should not have had such significant detriment to the performance of the airplane. However, it would be interesting to note where it was that this ice came from. Recall that the aircraft that was immediately in front, and the aircraft that was immediately behind, the Air Florida B737 in the takeoff line, took off with no problems. All three airplanes were deiced at approximately the same time. All three airplanes were exposed to the elements for approximately the same time. Yet two of the three flew successfully, and one did not. If it wasn’t weight, what prevented the airplane from flying? In my opinion, it aerodynamically stalled.

Pilots fly airplanes according to airspeeds, not power settings. Airplanes fly or fail to fly because of the wing moving through the air at sufficient or insufficient speed. Did this accident airplane have insufficient airspeed? No. The airplane reached a speed slightly higher than V2, computed to be 144 knots. At 20 percent above the stalling speed, this meant that the airplane would have stalled at 120 knots. In that any additional weight due to ice accretion seems not to be the answer, why did the airplane stall at 24 – 30 knots above stalling speed? In my opinion it was because of the pitch attitude of the airplane.

[AirRabbit]

The accident report describes “the Boeing 737’s tendency to significant(ly) pitch up in conditions where the wing was presumably contaminated by snow, sleet, or rain in near-freezing conditions prior to takeoff.” This phenomenon directly relates to asymmetrical lift. Asymmetrical or differential lift is not new, and is, in fact, used every day by every airplane that uses roll control spoilers. Asymmetrical or differential lift is used to assist not only in rolling the airplane, but in assisting in maintaining coordinated flight by compensating for adverse yaw. Here, however, in the B-737’s tendency to pitch up, the asymmetry comes not laterally but longitudinally. With the outboard portion of the wings sufficiently deformed by leading edge ice accretion, they provide less, or no lift, leaving the inboard portions of the wings (also farther forward) producing an asymmetrically large lift differential. As the airplane accelerated during the takeoff roll, the pilot, to ensure nose gear contact with the runway surface, normally would hold the controls in a forward, or nose-down, position. However, as the rotation speed is approached, the pilot is instructed to move the control column to a neutral or slightly aft of neutral position in preparation to initiate the rotation to the takeoff attitude. My opinion is that when this action occurred, or immediately when beginning the rotation, as the wing was rotated from an essentially negative angle of attack to a positive angle of attack, the inboard portion of the wing, producing virtually all of the lift being generated and that forward of the center of gravity, rotated the airplane, without the assistance of the pilot, and continued that rotation to a point where the wing was aerodynamically stalled.

An “aside” here, I think, may be appropriate. I know for a fact that the Air Force KC-135, Strato-Tanker airplane (essentially a hybrid of the original B-707 and the B-720)was equipped with roll control spoilers. However, additionally, the KC-135 had spoiler control valve switches (both of which were guarded switches) located just under the center of the glare shield. The left switch activated the inboard spoiler control valve and the right switch activated the outboard spoiler control valve. These valves were checked prior to each and every flight. What was their use? Well, that’s a questionable call about which many would not be willing to offer an opinion. Personally, I believe it was a safety feature that was made available in case loading of fuel in the massive fuel tanks located both forward and aft of the center of gravity created a longitudinal shift in that center of gravity that might needed to be managed. In fact, all instructors were trained on their use, as during takeoff, a pilot could reach up under the glare shield, open the left guard, depress the switch (thereby cutting off hydraulic fluid to the inboard spoilers) and without doing anything with the control column, reach down an raise the speed brakes (now, because of deactivating the inboard spoilers, only the outboard spoilers would respond – raising only the outboard spoilers) to create a differential lift on the swept wings of the KC-135, where the inboard portion of the wing is farther forward than the outboard portion of the wing – resulting in the outboard portion of both winds having the lift “spoiled” and the lift on the inboard portion remaining unchanged, the airplane would rotate smartly – so smartly, in fact, the speed brake extension had to be moderated to avoid driving the tail of the airplane onto the runway prior to becoming airborne. Asymmetrical lift is quite powerful.

In the accident B-737, if this condition existed, it is very likely that continued forward control column movement and continued forward pressure on the control column would be insufficient to bring the nose down. We see on the CVR transcript that the Captain is urging “Forward, forward.” “Easy.” “We only want Five Hundred.” “Come on forward.” “Forward.” “Just barely climb.” What do you think was going on in that cockpit? I think that the flight crew had the control column fully forward and the airplane was not responding the way they had expected it to respond. Speculation has been raised that trimming the stabilizer to its maximum nose down position may have been able to provide some additional nose down elevator authority. However, this action would have been completely non-intuitive to a pilot never having experienced this phenomenon previously, and being airborne for only 22 seconds would probably not have allowed sufficient time to allow the trim to achieve sufficient movement to make enough of a difference.

Interestingly, the accident report also states “there were other incidents similar to this one reported, in which the crew was able to overcome the contamination, but they needed the proper thrust level of 2.04 EPR.” I believe this statement inaccurately and unfairly characterizes the recoverability of any B-737 that has aerodynamically stalled due to a significant pitch up resulting from contamination of the wing by freezing precipitation. In support of this belief I call your attention to an occurrence on the same day as the Air Florida accident, with another B-737 operator’s experience out of Oslo, Norway. While perhaps one may be able to conclude that flight and ground personnel in Washington may misunderstand snow and ice conditions, there is no way that anyone is going to believe that pilots or ground crew in Oslo, Norway, are going to misunderstand the necessities or the procedures for deicing an airplane. However, on this day, the B-737 departing from Oslo was exposed to a snowstorm during taxi out and takeoff, and the problems experienced immediately after takeoff were chillingly identical to the Air Florida accident.

Because of the storm in Oslo that day, ice was built up on the wing leading edge. But, because of the nature of the storm, the build-up was asymmetrical. As in the Air Florida airplane, at takeoff there was a resulting pitch-up, but in Oslo, it was a rolling pitch (due to the asymmetry of the deformation). Even though the crew slammed the throttles to the firewall immediately, used full opposite aileron and full opposite rudder, they were unable to control the pitch/roll of the aircraft. Fortunately, because of the radical bank angle (approaching 90 degrees), the nose dropped back down to the horizon, and with the throttles fully forward, the airplane began to accelerate. As the airplane accelerated, lift was produced over the outboard portions of the wing, including the ailerons, and that allowed the crew to roll back to level flight. The crew did recover the airplane; but the recovery was below 100 feet above the ground. Had they not had this bit of inconsistency from Mother Nature, resulting in the asymmetrical lift on the wings, providing the roll, and allowing the nose to fall, the world would have seen B-737s on opposite ends of the world crash on the same day from the same problem.

I contend that this problem is a very slight accumulation of ice on the leading edge of the wing causes asymmetrical lift, longitudinally, resulting in a nose up pitching moment. The relationship is that the greater the accumulation of ice, the more asymmetrical lift, and the greater the pitch tendency. Perhaps there were some incidents where the crew was able to recover the airplane by, among other things, advancing the power. But in Washington and in Oslo, the ice build-up was sufficient to result in uncontrollable pitch. Even with both throttles full forward throughout the event, the Oslo aircraft was not recovered by assuring the engines were producing at least 2.04 EPR. In fact, had the differential lift been symmetrical, and the aircraft not rolled over on its own, full thrust on the under-slung engines on the B737 may have exacerbated the pitch tendency.

Is this what happened to the Air Florida airplane? I believe it is. Look at the CVR and the Flight Data Recorder (FDR) readouts. The CVR has the Captain calling “V2,” and scarcely 2 seconds later the transcript describes “sound of stickshaker starts.” When listening to the actual recording of the CVR there is little doubt that there are sounds of severe buffeting as well as the stick shaker operating. The airplane had gone well past the stall warning (the stick shaker) and had gone well into the stall buffet. Opinions differ as to what pitch angle would have been required to get into the stall buffet – but they range from 22 to 24 degrees of pitch. Think about that for a minute. In just over 2 seconds the airplane goes from level attitude to at least somewhere between 22 and 24 degrees of pitch. That is a rate of rotation in the neighborhood of 12 degrees per second. Recall that the normal rotation rate is 3 degrees per second; and the F/O, who was at the controls, had indicated he was going to “takeoff the nose gear and then just let the airplane fly off by itself.” The F/O wanted to deliberately limit the rotation to just getting the nose gear into the air, and the airplane was rotated at 12 degrees per second or more. Does that indicate anything inconsistent to you?

The bottom line is this. I have no explanation as to why one of the crew did not look more closely at the wings prior to departure. I don’t know why the crew was lead into accepting a clearance that would have been “challenging” on a clear day with unlimited visibility. I regret that we all didn’t know more about deicing effects and “hold-over” times. I don’t know why we were not made aware of the tendency of the B737 to have pitch-up and roll-off problems in winter weather conditions. What I do know is that I am grateful that the errors made that day, by all who made them, have been talked about and hopefully will be used to educate others and save lives. I also know that two competent aviators, former colleagues of mine, and extremely nice young men, lost their lives, as did most of the rest of those on board the airplane along with four motorists who died on the bridge that fateful afternoon.

My only goal in providing this information is to provide at least an alternative to the understanding that many have had for a number of years. I believe that the real cause of this tragic accident wasn’t because these young men forgot to use, or chose not to use, engine anti-ice. The acceleration rate was immaterial. It was not because they attempted to power-back out of the gate. They did not do that. It was not because they chose to “deice” their airplane by deliberately taxiing too close behind other aircraft “jet wash.” I don’t believe they did that. It was not because they disregarded the snow that accumulated on their aircraft while waiting to takeoff. I believe they placed their confidence in the deicing / anti-icing process. It was not because these professional pilots lacked critical knowledge of cold weather and de-icing operations. (I probably should point out that prior to being hired at the airline, the F/O who was at the controls of the accident airplane, had been an F-15 pilot stationed at Minot, North Dakota – where, as everyone probably knows, the residents do have something more than a nodding acquaintance with ice and snow.) I am firmly convinced that the accident was caused by the fact that the airplane was highly susceptible to very minor amounts of ice deformation of the leading edge of the wing; that it was caused by the fact that they were deiced with an inadequate system that coated their aircraft and engine intakes with water – and only a small token of the glycol solution on which they depended.

I believe that once this crew pushed the throttles forward with the intent to takeoff, they were doomed. The only way that an accident could have been avoided at that point, was to have kept the airplane on the ground until a sufficiently higher airspeed was reached prior to initiating the rotation. Unfortunately, not only did the crew not know that this would be necessary, they wouldn’t have known the “magic” airspeed number. Even if they had pushed both throttles all the way to the firewall from brake release, and then rotated at the computed rotation airspeed (as they did) the airplane would have performed in exactly the same way. It would have uncontrollably pitched up to at least the 22 – 24 degree attitude; likely more given witness statements … where some said they saw “the aircraft was flying at an unusually low altitude with the wings level at a nose-high attitude of 30 degrees to 40 degrees before it hit the bridge.” It would have entered the same deep aerodynamic stall. The flight crew would have been unable to bring the nose down aerodynamically. Unfortunately, in that condition, full thrust on both engines would have been insufficient to maintain flight. All who were affected by this tragedy were victims of longitudinal differential lift. The flight crew did not have the luxury of time to analyze, consider, and choose accordingly.

[Cagedh]

OK AirRabbit, I'll bite. What did cause AF to go for a swim?
From the NTSB report of the Air Florida crash states: (still relevant, 30 years later!!)

Bravo AirRabbit, :D

You certainly have my attention there. I'll reread the full NTSB report and your posts over the coming days. You certainly do seem to know the case very well!

[8sugarsugar]

I was under the impression that the crew never firewalled the throttles, even AFTER airborne.

The aircraft pitches up to 22 degrees, with both hands on the yoke pushing down with all their might, how many of us would take a hand off the yoke and push the throttles forward?

I believe the crew is wrongly criticized for pilot error "at this point" in the error chain. We are all human and without prior experience or knowledge, it would have happened to every single one of us.

Its human factors, in our brain we set T/O EPR, uncommanded pitch to 22degrees, stick shaker, we push down with all our might with both hands...

the end

[Mike-Bracknell]

no being anything but an aircraft enthusiast
i saw earlier that i costs $4000 to de-ice a 747,not much less for 777's and the like i expect
how do airlines make a profit on that particular flight ?
from what i've read over the years on flying seems to me some flights won't break even ?

If it costs $4000 (per flight? per day? per?) to de-ice a 747, I wonder what the break-even would be on hangaring an entire hub to prevent the issue at especially prone airports?

[AirRabbit]

I was under the impression that the crew never firewalled the throttles, even AFTER airborne.

The aircraft pitches up to 22 degrees, with both hands on the yoke pushing down with all their might, how many of us would take a hand off the yoke and push the throttles forward?

I believe the crew is wrongly criticized for pilot error "at this point" in the error chain. We are all human and without prior experience or knowledge, it would have happened to every single one of us.

Its human factors, in our brain we set T/O EPR, uncommanded pitch to 22degrees, stick shaker, we push down with all our might with both hands...

the end
Actually, they did get both throttles to the firewall … but it was far too late for that to have had any effect on things. However, we should recognize that with the underslung engines on the B-737 any increase in thrust is going to provide a tendency to further rotate around the lateral axis (i.e., pitch up). When being nose-up is the problem, not many would think that adding a nose-up pitching moment would be a very smart thing to do.

I know that I indicated that most people believed that it would take a minimum of 22 – 24 degrees of pitch to actually enter an aerodynamic stall – where buffeting of the airplane could not be overlooked. If you consider any of the eye-witness accounts to be even close to accurate, the airplane achieved substantially more than 22 – 24 degrees of pitch. Several eye-witnesses estimated the pitch to be higher than 30 degrees and a couple estimated the pitch attitude to be 40 degrees. These estimates were not given as numerical values - each witness formed an angle with his/her hands and the investigator selected the numerical value he thought was appropriate. And, as I’ve pointed out on more than one occasion, the F/O clearly said that what he was going to do was “…take the nose wheel off and then we'll let it fly off.” How much pitch attitude do you think would have been just enough to raise the nose gear off the surface? The other question would be … just how surprised would you be if, when planning to rotate to something like 10 or 12 degrees of pitch, as you begin to move the control column aft, the airplane rotates up to 12 degrees and immediately goes up to 20 … then 25 … then 30 … then 35 degrees! You have your flying partner yelling in your ear “…come on forward. Forward. Just barely climb. Forward. Forward.” What do you think you’d be doing?

[BobM2]

Many thanks for that very well thought out analysis AirRabbit. Makes more sense than the NTSB report which I never considered a complete enough explanation. I assume the difference in lift degradation between wing outer & inner sections is due to Krueger flaps inboard & slats outboard. I could see how ice would affect slats more, especially if the flaps were left up during the ground delay.

[Machinbird]

Nice analysis AirRabbit:ok:.
That particular NTSB report always bothered me-felt like something was missing.

[lomapaseo]

Does a B737-200 engines really cause it to pitch up when advanced ?

[BobM2]

Yes, any aircraft with the thrust line below the cg has this characteristic. This includes many current jet transports.

[8sugarsugar]

the pitch up tendency of underslung engines is negligible when you're <50 feet off the ground. You want that thrust vector regardless of increased pitch moment.

Jets can power out of stalls and still climb when buffetting.

[gatbusdriver]

Depends on stab trim.

BOH TUI 737 had slowed down on finals with A/P engaged and manual thrust (either at idle, or too little thrust). Aircraft trimmed to maintain glide as IAS reduced, on commencing the missed approach the pitch couple caused by advancing the thrust levers caused a nose up moment for which they did not have enough elevator authority to overcome unless they trimmed forward.

[Clandestino]

:D Well done AirRabbit! Your interpretation of Air Florida 90 catastrophe reminds me of the theories put forward by the legendary captain Dudley; inoffensive and convincing, inter alia. Capt Gann would describe it as verbal magic.

Nevertheless, for anyone interested more in history than alternate history, NTSB report provides better value-for-time-spent-reading. Especially CVR transcript.

Back to topic: issue with pilots not understanding where lies the problem with taking off with contaminated wings was well understood by a certain gentleman of yesteryear:

The problem with most pilots is that you are spoiled. And lazy. You have never taken the trouble to learn mechanics properly.

Replace "mechanics" with "aerodynamics and statistics" and there you have it.

Here comes winter refresher; a bit of talk what is new, a lot of talk of what we should all already know, compulsory video of Dryden or Palm ninety in front of mixed audience, from grey-haired veterans to greenhorn effohs. Some young ones learnt their aerodynamics by rote and forgot most of it after passing the exam. All they hear is "Blah, blah, blah... you will die if you don't de-ice.... blah, blah, blah". Then one day they get paired with captain of similar background but earlier "joined" date who is not concerned with a bit of snow on wings as it will all blow off and anyway and skipping the de-icing will save company time & money. Our young hero is a bit scared as he still remembers the educational videos but while he weighs whether to believe ground instructor of couple of weeks ago or the capt sitting with him here and now, vee one has passed. Then rotation. Then "POSITIVE RATE" and aeroplane flies. And flies. Now there is no doubt who was right, is it? So the "de-icing gives false feeling of security" and "it satisfies the feds" attitude towards ground de-icing continues its spread among the pilots. One day our young hero will be captain. Experienced captain.

If you're not much into flying: point is that very little percentage of aeroplanes that take-off with contaminated wings end up as tangled wreckage near the runway's end; any contamination will eat up into stall margin but if that margin is not completely taken away, aeroplane will fly. However, even that little percentage is both easily manageable and unacceptably high in public air transport. Pilots failing to get to grips with basic aerodynamics are main source of old-wives-tales, refuting the standard op procedures. Not just on cold wx ops.

[lederhosen]

Clandestino I am seriously confused about what you are trying to say and what it has to do with the original thread. Are you saying AirRabbit does not understand aerodynamics and is telling old wive's tales?

Flying jets is a team activity, both pilots are involved. I can certainly remember when I was a co-pilot telling a captain at the holding point after a heavy snow shower that we needed to de-ice and us going back and doing so. I expect and encourage my co-pilots to do the same.

[up_down_n_out]

"Jets can power out of stalls and still climb when buffetting"

Yea right, pity AF447 went straight down, and they were saying exactly the same as you, right to the end.

Sounds like utter b..ll x to me, especially in a deep stall.

[AirRabbit]

Jets can power out of stalls and still climb when buffetting.
The Airborne Express DC-8 flight crew ... who were conducting a post-maintenance flight test on the night of December 22, 1996 in Narrows, Virginia, that included an approach-to-stall maneuver entered at 17,000 feet, repeatedly attempted to recover by simply “powering out” of the condition as you suggest ... might want to differ with that opinion, and probably would, except they are no longer with us to voice that difference, as they all died in the ensuing crash.

[Lightning Mate]

http://i636.photobucket.com/albums/uu82/Lightning_29/contaminatedwing.jpg

[8sugarsugar]

I guess what I was trying to say, if your two options are in Air Florida

1. not advancing power levers in fear of pitch up moment and crashing anyway

2. advancing power levers, accepting increased pitch up moment and praying to god you get at least 500 ft.

At least with #2, you hit terra firma softer and save some lives.

what would you do?

[stepwilk]

Air Florida had absolutely nothing to do with the crew fearing a pitch up.

[AirRabbit]

Clandestino I am seriously confused about what you are trying to say and what it has to do with the original thread. Are you saying AirRabbit does not understand aerodynamics and is telling old wive's tales?
I’m also confused about what Clandestino is saying. But, if I'm interpreting it correctly, I differ with his opinion that my post is an “alternate history,” providing a “verbally magic” rendition of the “real” history as contained in the NTSB report. I agree that everything in the NTSB report is based on fact but is not necessarily factual. Unfortunately, the analysis of those facts is, at best, incomplete – and in some cases, the facts presented are either dismissed or overlooked in the development of the final position … and in other instances, facts or statements from witnesses were omitted from the report.

Just one example (and there are others): in the report, on page 9, there is “grainy” photo of the accident airplane at the gate prior to departure. This photo was reportedly taken between 15:19 and 15:24, by a passenger on an arriving flight that was holding for gate space near the accident airplane. The photo shows snow accumulated on the top and right side of the fuselage. This photo was used to present the case that the airplane had accumulated snow or ice prior to departing the gate, further condemning the flight crew for taking off under such conditions. However, in the referenced photo, the forward cargo door (below the windows) is clearly open and baggage carts and a catering van are positioned adjacent to that open cargo door. Statements acquired of the crew that actually deiced the airplane indicated that they accomplished the deicing after all baggage had been loaded and the airplane had been catered and that after the deicing, no additional baggage was loaded and no additional catering was completed. These statements did not make it into the report. Why? It’s only my opinion, but, if someone wanted to provide evidence that the airplane was “covered with ice and snow,” the photo certainly validates this truth. However, if the photo was taken prior to the deicing process – that piece of evidence no longer contains valid information relative to the condition of the airplane when it left the gate, and therefore becomes meaningless. The timing of the photo was an estimate provided to the investigators by the passenger who took the photo from the window of a flight inbound to the gate.

Anyone reading the CVR transcript can see that it starts at 15:30 – meaning that 15:30 would be after the passengers and crew had boarded the airplane; after all the all the commotion that accompanies boarding the airplane; after the flight crew had competed their cockpit checks; after the engines had been started the first time; after the first aborted attempt to push back; after the second aborted attempt to push back; after the engines had been shut down; and after the call for another, larger tug to push back. In fact, at 15:34 the Captain is noted as saying “Here comes the chain tractor” (meaning the tug with chains on the tires to facilitate the push-back process). Again, look at the photo. Could the baggage have been loaded, the catering completed, and then the deicing/anti-icing process completed on the entire airplane (whether or not the mixture was adequate to do the job intended), for all of the above to have taken place, including the accumulation of ice and snow indicated in the photo – and have that all accomplished in 6 - 12 minutes? Give me a break!

Conclusion: The photo provided visual confirmation of the facts only if interpreted in one way. The statements provided by the deicing crew would have conflicted with this interpretation of facts. However, by relying on this photo and disregarding the statements made by the deicing crew, one would have to conclude that what is seen in the photo is not the baggage door open and there are no baggage carts or a catering vehicle at the airplane visible in the photo; OR that catering and baggage loading occurred after the deicing process was completed. Also, one would have to presume that the photo was taken sufficiently long enough after the deicing was completed to have had that kind of accumulation occur, and that all of the above cited events would have had to have taken place in the 6 to 12 minutes between when the photo was taken and the CVR transcript beginning. Does that make sense to you? Not in my book! The only logical conclusion that can be made is that the photo was, indeed, taken by a passenger on an arriving flight – but it was taken much earlier than described – well before the deicing / anti-icing process was conducted. So why include it? I think the answer is obvious.

[AirRabbit]

Air Florida had absolutely nothing to do with the crew fearing a pitch up.
:confused:
…and you absolutely know this because …??

[AirRabbit]

I guess what I was trying to say, if your two options are in Air Florida
1. not advancing power levers in fear of pitch up moment and crashing anyway
2. advancing power levers, accepting increased pitch up moment and praying to god you get at least 500 ft.
At least with #2, you hit terra firma softer and save some lives.
what would you do?
I have said from day one that had the flight crew pushed the throttles to the firewall at brake release … and initiated the rotation at the computed rotation speed – exactly the same thing would have occurred … except – as you note – because of the aircraft attitude, the downward thrust vector may have (no guarantee … but may have) allowed the airplane to miss hitting the bridge and the 4 lives lost on that bridge would likely have not been lost. However, the location of the eventual impact (and there would have been an impact) would more likely have been closer to the middle of the Potomac River, although more upstream, making rescue of those who were rescued a lot more problematic. Who is to say what would have been the most advantageous decision? What I suspect is that throughout the entire 28 seconds they were airborne, they were trying to figure out what to do to fly the airplane – heck, here we are some 30 years (!) after the fact … and I suspect there still isn’t a consensus.

[Clandestino]

Clandestino I am seriously confused about what you are trying to say That's because you have never met captain Dudley or anyone of his ilk... smooth-talking, very convincing and stupefyingly ignorant if you happen to know a bit about issue being discussed.

Are you saying AirRabbit does not understand aerodynamics and is telling old wive's tales? How in the world could I possibly know whether AirRabbit understands aerodynamics? I don't know (and don't care either) who AirRabbit is, all I have and have referred to is his alternative analysis of QH90 accident. Some of the points he made are so out of sync with the real world that it would be tragic if real pilots hold them to be true. First issue with QH90 was very primitive (but legal at the time) FDR, which did not record attitude or power. In AirRabbit's alternative view on the accident, holes left by primitive recording equipment are filled by conjecture, yet that CVR recorded both pilots clearly pouring their derision on the de-icing procedures during taxi-out is conveniently omitted.

Opinions differ as to what pitch angle would have been required to get into the stall buffet – but they range from 22 to 24 degrees of pitch.Such a blatant mix-up of pitch and AoA I find hard to comprehend but then I was the lucky one, flying unstalled at +90° pitch and being stalled at -60° before my TT went into three digits.

the airplane should have been able to fly on one engine at 100% powerWith clean wing, it would. NTSB is pretty clear on that.

In that any additional weight due to ice accretion seems not to be the answer, why did the airplane stall at 24 – 30 knots above stalling speed? Weight of the ice being significant factor is myth dispelled during first hour in winter ops groundschool. so far so good.

In my opinion it was because of the pitch attitude of the airplane. Wrong!!!! Issue is not pitch but lesser Cl max, higher Cd and lesser AoAcrit which is not due to...

the outboard portion of the wings sufficiently deformed by leading edge ice accretion
...but rather upper wing skin contaminated by ice! Top of the wings is the most critical surface for contamination on any aeroplane!

I believe that once this crew pushed the throttles forward with the intent to takeoff, they were doomed.They could have aborted. The B727 you are so concerned about would have gone around. Happens every day. Very seldom makes headlines.

I suspect there still isn’t a consensus.
How do you make consensus with someone obviously unable to understand the accident report? Why would there have to be consensus with such a personae?

Don't trust NTSB blindly but at least make an effort to understand what they are saying. You'll find their analyses correct far more often than not.

[lederhosen]

Thank you Clandestino for taking the time to clarify what you meant. But I cannot see what we are arguing about. AirRabbit has suggested that the AirFlorida aircraft pitched up sharply after takeoff. One thing we can all agree on is that it was snowing heavily as apparently with the Aeroflot aircraft getting back to the original thread. There is no way of knowing how an aircraft covered in contaminant will behave. Ice and snow on the horizontal stabilizer for instance could also significantly change the flying characteristics. It is the luck of the draw if you get away with it. The message is don't do it. Even if you do not crash you can expect to be confronted with the evidence on youtube!

[Checkboard]

AirRabbit, interesting take on the Air Florida case.

All wings are unstable in pitch, the centre of lift moves forward as the aircraft pitches up. If it moves too far forward on a less stable wing, especially one with a wide chord, it can exceed the pitch authority of the elevator:

F-4 Phantom Stall & Crash - YouTube

(Perhaps especially if a close taxi to an aircraft in front melts some of the ice on the inboard wing and not the outboard sections?)

... it would be interesting to see some research on the amount of pitch up moment a 737 could develop under those conditions for me to be convinced, though. I think it's certainly worth that research.

[lomapaseo]

Clandestiono

First issue with QH90 was very primitive (but legal at the time) FDR, which did not record attitude or power. In AirRabbit's alternative view on the accident, holes left by primitive recording equipment are filled by conjecture,

By the time of Air Florida it was common practce for the CVR analysis group to consider water fall chart analysis of the CVR traces to track the N2 frequency signal from each engine to assess actual engine power vs time.


It's easy for some to suggest that wing contamination might have played a part (after all the evidence melts immediately after a crash).

However the validated contributions are covered in the NTSB report hence the recommendations regarding engine power set "check'.

The Forum thread we are burried within is an equally important opportunity thread to discuss wing ice as a prime consideration on its own without mixing it up in a controversial message about Air Florida in the Potomac

[stepwilk]

…and you absolutely know this because …??

Because I read the NTSB report.

[AirRabbit]

Because I read the NTSB report.

My appologies ... I must have missed that information in the report ... do you have a page reference?

[AirRabbit]

I don't know (and don't care either) who AirRabbit is, all I have and have referred to is his alternative analysis of QH90 accident. Some of the points he made are so out of sync with the real world that it would be tragic if real pilots hold them to be true. First issue with QH90 was very primitive (but legal at the time) FDR, which did not record attitude or power. In AirRabbit's alternative view on the accident, holes left by primitive recording equipment are filled by conjecture, yet that CVR recorded both pilots clearly pouring their derision on the de-icing procedures during taxi-out is conveniently omitted.
Of course it is true that the CVR contained “evidence” of what you refer to as the “derision” of de-icing procedures maintained by the flight crew. My contention is that such conversations were more routine than scarce among aviators at that time … not due to the scorn felt, but, to the contrary, due to an attempt to present an attitude of fearlessness and “macho-ism” that airline pilots were historically supposed to exhibit. However, when “push-came-to-shove,” I think it was rather routine to find everyone eager to participate in whatever was the “science of the day.” It’s just that the science of that day is not the science of today. The conversation between the two flight crew members wasn’t omitted from my comments in a “convenient” attempt to hide what was happening, but was omitted because it was irrelevant to the points I was attempting to make.


Such a blatant mix-up of pitch and AoA I find hard to comprehend but then I was the lucky one, flying unstalled at +90° pitch and being stalled at -60° before my TT went into three digits.
I guess you are one of those guys who read the specific words and responds only to those words, not bothering with what one can glean from those words. OK, I’ll go with that approach. If it makes a difference, I do understand the difference between “pitch” and “AoA” and I’m fully aware of the fact that an airplane can be stalled in any position relative to any particular reference. I’ll accept the criticism for not being more specific with respect to the differentiation between“pitch” and “AoA,” I just thought it might be easier to understand my position by referring to the attitude of the airplane, (“pitch”) in that no one really knows the specific AoA that was achieved … and with a lack of information as to the actual flight path of the airplane, even a good guess is not terribly likely.


the airplane should have been able to fly on one engine at 100% power
With clean wing, it would. NTSB is pretty clear on that.
I guess I didn’t make myself perfectly clear. Obviously something caused the pitch attitude (read that as AoA if you prefer) that was achieved. That attitude was due to either the flight crew placement of flight controls or some other aerodynamic force. Given the concession that it was not likely the flight crew that pulled back on the controls to the extent that would result in the pitch attitude (AoA) eventually achieved – it must have been some aerodynamic issue. Also, one of the contentions was that the reason for the crash was the fact that the flight crew used less than full power. Of course, they used less than full power – and that was an error – but it did NOT cause the accident. Under normal circumstances (as you correctly point out) the airplane would have flown on two engines producing 75% of maximum thrust of each engine. The point I was driving to is the fact that there was another reason that the crash occurred. It was the ice that was present on the wings … but … (and this is why I made such a point about the airplane preceding and the airplane following the accident airplane) all 3 airplanes were deiced at about the same time … all 3 airplanes were exposed to the same elements for about the same time span … yet it was only the middle airplane that crashed. What was different about this airplane? The difference was the deicing procedure used on this airplane – only this airplane. This is the reason I went into the detail that I did regarding the equipment that was used to “de-ice” the airplane. The aerodynamic force that was responsible for the resulting attitude (AoA) was a result of the ground crew de-icing the airplane with hot water – and then going back to “over-spray” the entire airplane with that same hot water. The reason the PT2 probes were blocked (likely with ice) is due to the fact that the de-icing crew sprayed hot water all over the engine intakes and then went back and lightly misted those intakes with that same hot water. It is my contention that this caused a very thin, transparent film of water on the lifting surfaces … which then froze into clear ice – probably barely detectable and certainly not able to be seen from the cockpit – probably not able to be seen unless very close to the contaminated surface – if then. Yet, the deformation it produced was significant enough to cause an unwanted and unexpected change in the aerodynamics affecting the flight of that airplane. I also went into some detail about asymmetrical lift on the wings – both laterally and longitudinally. It was this longitudinal differential lift that caused the unwanted and unexpected pitch-up, and did so to an unwanted and unexpected attitude – placing the airplane in an unwanted and unexpected AoA from which recovery was not possible under the circumstances.


In that any additional weight due to ice accretion seems not to be the answer, why did the airplane stall at 24 – 30 knots above stalling speed?

Weight of the ice being significant factor is myth dispelled during first hour in winter ops groundschool. so far so good.
Thanks for that.


In my opinion it was because of the pitch attitude of the airplane.

Wrong!!!! Issue is not pitch but lesser Cl max, higher Cd and lesser AoAcrit which is not due to...

the outboard portion of the wings sufficiently deformed by leading edge ice accretion

...but rather upper wing skin contaminated by ice! Top of the wings is the most critical surface for contamination on any aeroplane!
We can discuss whether or not the change in lift characteristics of the accident airplane was due to leading edge contamination or wing surface contamination if you care to … but I’m going by Boeing’s own reports of the B-737 being susceptible to “pitch-up, roll-off tendencies when exposed to areas of freezing precipitation encountered in flight during the original flight testing of the airplane.” As you would recognize, ice buildup due to inflight encounters does not occur on the wing’s top surfaces as much as it does on the wing leading edge … but, deicing a wing with hot water is as likely to deform the wing surfaces as much as the wing leading edges … and, as I said, this particular discussion may be appropriate at a later time. The fact is that the wing was deformed – not by the falling precipitation (recall the other two airplanes in line … one preceding and one following the accident airplane – all of which were exposed to the same falling precip), but rather by the “de-icing” procedures completed at the gate.


I believe that once this crew pushed the throttles forward with the intent to takeoff, they were doomed.

They could have aborted. The B727 you are so concerned about would have gone around. Happens every day. Very seldom makes headlines.
Of course they could have aborted, and I’m acutely aware of the number of rejected or aborted takeoffs that occur – and I’m also aware that “go-arounds” are quite common. However, these kinds of activities when occurring together are not routine, particularly when the weather conditions are as poor as they were on this fateful day. If the B-737 had aborted at the first question raised by the F/O and had that information been relayed immediately to the tower and the approaching B-727 crew had been listening intently, understood the meaning, and executed a missed approach – there is a chance that there would have been no problem. But given that the visibility was “el stinko” (tower quoted the runway 36 visual range to be 2800 feet with the sky completely obscured) AND the fact that the B-727 was very, very close behind the B-737 (some witnesses said both airplanes were ON the runway at the SAME TIME!) it is highly unlikely that everything would have worked out in a pristine manner – and, while it may not be a universal suspicion, the suspicion is certainly held by more than a few aviation professionals, that had that B-737 aborted on the runway, it would likely have been hit by the landing B-727, either on the ground or during the attempt to go around … and that is what I think was on the mind of the Captain of the B-737.

I suspect there still isn’t a consensus.

How do you make consensus with someone obviously unable to understand the accident report? Why would there have to be consensus with such a personae?
Don't trust NTSB blindly but at least make an effort to understand what they are saying. You'll find their analyses correct far more often than not.
Come on Clandestino … I’m trying to go out of my way to keep from insulting you … don’t you think that a little more restraint might be in order? I was responding to “8sugarsugar” when he asked if I would add power or not add power were I in the same situation. Because of the notoriety of this particular accident … because it is one of the few accidents ever to occur in the US capital … because every news outlet on the planet had consistent news coverage of this event for weeks afterward … I would be shocked to see that more than just a couple of people could ever find a consensus on more than a few areas with respect to this accident. It may be proven wrong in some circles, but as of now, at least I think I can read the English language as well as most everyone in this country – and I think I am reasonably familiar with aviation and how it works. I think I’m also familiar with accident investigation and as I said at the outset of the posts I made yesterday, my motivations have NOT included an intent to impugn the fine reputation or the integrity of the NTSB or of the dedicated and professional employees at the Safety Board; rather my intent was, as I stated … a continuing effort to describe the actions of the flight crew from a slightly different perspective while providing what I believe to be clarifying information regarding the cause of the accident to the best I am able. Now, if you tell me that I’m not authorized to post my opinions on something – that’s a completely different issue. As anyone on this or any other forum is always free to do … you are free to disagree and argue with my opinions if you desire – but they ARE my opinions.

[stepwilk]

My appologies ... I must have missed that information in the report ... do you have a page reference?

I'm not gonna do your work for you.

[AirRabbit]

Yeah ... that's what I thought.

[Machinbird]

Checkboard,
The video of the Phantom pitching up was taken of an early test hop at the McDonnell factory. They apparently did not have any stabilator control at all and it was stuck full nose up.

[8sugarsugar]

Any old Eastern guys out there? Flew with a few that talked about DC-9s with a foot of snow on the wings.

un official procedure was,

1. make sure you have >88% N1 t/o thrust
2. Vr + 20
3. snow blows off

[reracked]

If we are talking early DC9 10-15 with no LE devices, that is insanity.

The number of crashes involving swept wing jets with no LED's is evidence of that.

[Connetts]

I'm self-loading freight.... now, an aged bitterly frustrated (by youthful circumstances beyond my control) wannabe from following the career I was designed for, which was to fly professionally like you guys. Then, late in life when I was able to afford to go for a PPL and just about to solo I dissected my aorta. That was quite a bad-hair day and ended my flying totally.

Meanwhile I had become an academic lawyer with a specialist interest in criminal law, and have focused (and published some papers in learned journals) on the criminal law aspects of flight safety. Now retired, I still read avidly and still do try to think about the theoretical basis of safety.

I watched the video that started this thread with interest and surprise. It is really ugly. As far as I can recall, nowhere in anything that I have read does it say that one may take off with an ice-contaminated aircraft "provided that.....". The quotations by UUWUDZX (posting 208) from the Airbus manual seems to sum up what I always thought the situation to be.

During my short-lived flying training I recall my instructors teaching me that, while there may be some interest in defining the different forms which ice can take, they all have one thing in common: anywhere on an aircraft, ice is to be presumed to be incompatible with safe flight, and it is certainly poor airmanship to try to take off without determining that there is none.

Reading what I have done on this thread, something else comes across forcefully to me. The fact that some contaminated aircraft have successfully taken off and flown while others have failed actually highlights the dangers of ice: its effects are unpredictable, and accordingly to be avoided. One contributor to this thread pointed out that even loose dry snow can hide problems. Empirical ad hoc research into whether one can successfully take off or not thus seems to be of no value, and to be discouraged.

So may I ask: aside from the cost of the process and delay, for what reasons would a pilot with passengers on board and who was aware of ice decide not to de-ice? If the reasons are only cost and delay, then surely pressure from the accountants must be resisted?

The impression I have formed in seeking to understand some of the theory underlying safety is that one would always try to avoid having to make subjective and discretionary judgements on safety-critical issues. A yes-no, black-white, on-off situation is preferable to one in which one has to use one's judgement, and this forms the basis of the cliché to the effect that if there's a doubt then there is no doubt. If this is correct, then am I also right to think that the typical professional pilot prefers to fly as routinely as possible, but trains for emergencies in a simulator hoping that the skills so acquired will never be needed? If this analysis is correct, why would pilots want to be in a situation in which they would look at ice and say, "Well..... I wonder.... maybe.... oh, we'll give it a go"?

From a legal point of view, my interpretation of all the "endangering" legislation I have looked at is that even if one succeeded in taking off and flying then one would still have been committing an offence precisely because the effects of ice are unpredictable. It would then be sufficient to prove recklessness (crudely, knowing disregard of the dangers) if one knew of the ice on the airframe; or if one knew that, in the prevailing conditions, there might be ice but decided not to check. In this case, one should be deemed to have known that there was ice (even, in fact, if there was none...... which is an interesting thought -- in addition to other forms of ice, we now have virtual ice!).

As a matter of prosecution policy, it seems that the point of view of the industry with all its muscle is one of "heads we win, tails you lose": if the aircraft took off and flew (I won't say "safely"), a prosecution is unlikely as a matter of policy and anyway the probability is that nobody significant will have noticed. If the aircraft crashed, then who's likely to survive to be prosecuted........?

The criminal law is a blunt weapon, but if its use is for deterrence then the policy behind prosecutions is flawed. I'd like to offer a comment or three.

Early on in the thread (eg pudoc, posting #28, is typical) some contributors remarked that they would intervene if they were passengers. The trouble with this is that it's too random and uncertain -- it presupposes a knowledgeable and confident passenger at a window seat.

On the other hand, why not formalise the situation? May I ask: is there any SOP which requires ground personnel proactively and routinely to draw the commander's attention to safety-critical issues regardless of whether the commander is or may be aware of the matter? If one assumes a worst-case scenario, the crew may (without necessarily being at fault) be unaware of ice; do ground personnel have no duty to raise the alert? As the final decisions are the commander's, receiving a formal alert would put great pressure on the commander to address the matter.

My thinking here is that one problem is, as I see it, that human beings have the capacity to talk themselves into doing the most unreasonable things. My lay understanding of CRM training is that this is addressed. Something is sometimes needed to break the causative chain before it matures into catastrophe. Would it be too invasive of the commander's discretion if someone on the ground had the authority to delay departure until either the aircraft has been de-iced, or the commander has explicitly overruled the delay?

Apart from anything else, this would create solid evidence of recklessness if it was needed in subsequent criminal or disciplinary proceedings.

But the penal sanction can be a pretty blunt weapon and is easily used inappropriately. During my working years as an academic, I realised that we don't always ask what, precisely, we hope to acheive by the use of the penal sanction (and I include internal disciplinary proceedings). I would have thought that here it is not to exact vengeance, but to prevent the harm from happening. The fact that more people than just the pilot would now be involved suggests to me that the criminal sanction can be exploited to create a culture of "I do not and never would do a thing like that, nor should anybody else, and the intervention of the ground personnel has been helpful in securing that objective standard."

[wiggy]

Machinbird


The video of the Phantom pitching up was taken of an early test hop at the McDonnell factory. They apparently did not have any stabilator control at all and it was stuck full nose up.

:ok:

Agreed, I'm really not sure what relevance that video has to the thread since it wasn't a case of running out of stabilator authority...

As I heard it the story behind the video is that there was a loss of both powered Flight Contol hydraulic systems ( PC 1 and PC 2) and therefore, as you rightly say, there was no stabilator control at all.

[Regulation 6]

Connetts - highly informative and erudite post. Thank you Sir

[reracked]

As a point of interest, what are the chances that the 2 "spokespersons" from Aeroflot would have quoted the same misplaced platitudes , had they been viewing the video recording at an accident investigation hearing. . . . . the images having been downloaded from a charred machine extracted from a pile of smouldering wreckage at the end of the runway.

I would suggest fairly slim. :hmm:

[M.Mouse]

I second Regulation 6's comment.

I have nothing much to add to Connetts post except to answer his question:

May I ask: is there any SOP which requires ground personnel proactively and routinely to draw the commander's attention to safety-critical issues regardless of whether the commander is or may be aware of the matter?

In a perfect world a sound idea. In the late 90's I was departing Newcastle in a B757. My co-pilot's sector, therefore he had done the walkround. Conditions were cold with light rain/drizzle/sleet. He mentioned to me after his walkround that we might need de-icing but was unsure and had asked the ground engineer to check the wings before push-back.

The ground engineer advised that we didn't need de-icing. During taxi out my co-pilot, a relatively new hire but very experienced RAF fast jet pilot, said he wasn't happy and would I mind if he went into the cabin to look at the wings from a window. When he returned he was very angry and informed me that he could clearly see frozen deposits. We returned to stand and found significant ice on the wings.

I didn't need to say much to the ground engineer after my co-pilot had forcefully pointed out a salient fact or two!

My point being that commercial pressure, time pressure (delays can ruin a stations delay statistics) or sheer idleness and complacency would all play a part. There is but one arbiter regarding de-icing or not and that is the captain.

I have in my career several times experienced engineers (a jolly fine bunch in general) being less than frank when trying to convince me an aeroplane is fit for departure.

I am fortunate that my company (British Airways) will never discipline a captain for making an honest, safety related decision, no matter how costly. If the decision was wrong there might be an informal debrief to examine how things might have been done better but nothing more. That does remove one massive source of pressure from a captain.

Regrettably British Airways and many other reputable airlines with a sound safety culture are by no means the norm, especially when one looks at countries where there is a culture of corruption and a less than rigorous attitude to maintenance and SOPs.

There is no panacea and it scares me to read some of the comments from professional pilots justifying attempting a take-off without a clean wing.

[dg808c]

yup russia......NOTE to self, never fly with a russina company. Why do we keep seeing this, I myself witnessed a russian 757 takeoff from gardamoen oslo with 10-15 cm snow on the wings.....we all figured he would crash at the end of rwy butttt noo, he got airborne on the very last meters. stupid :bored:

[AirRabbit]

I’ll add my compliments to those of Regulation 6 and M.Mouse … and add one additional comment …
There is no panacea and it scares me to read some of the comments from professional pilots justifying attempting a take-off without a clean wing.
As the former US FAA Administrator said repeatedly, “we cannot legislate professionalism,” and I think most everyone would agree – certainly I do. The precepts of professionalism that are most regularly described typically include attitude, competence, conduct, and perhaps above all, character – none of which, perhaps with the exception of competence, lend themselves very easily to a set of recognizable standards.

This is the underlying reason that in an earlier post I pointed out the regulatory requirement that addresses taking off with contaminants posing a safety risk, and attempted to point out why it may be that many (most?) of those pilots who seem to treat wing contamination with less respect than others … do so with confidence that governmental officials are of the opinion that only extreme cases warrant a particular response, and situations not as extreme may be disregarded and a continuation of “ops normal” may proceed. The reference is 14CFR §91.527(a) and it says, “No pilot may take off an airplane that has frost, ice, or snow adhering to any propeller, windshield, stabilizing or control surface; to a powerplant installation; or to an airspeed, altimeter, rate of climb, or flight attitude instrument system or wing…” (my emphasis added). To many, this requirement just may indicate that as long as a contaminant isn’t known to be adhering to the wing, particularly if it’s snow that has just recently fallen on the wing’s surface, it’s perfectly acceptable and certainly legal, to takeoff. The video at the start of this thread would seem to verify that there continues to be those who likely maintain this understanding and act accordingly. I’m not offering excuses … I’m suggesting that we haven’t yet done “all we can” to eliminate potentially confusing signals to those who do this job regularly.

[rgbrock1]

AirRabbit wrote:

The precepts of professionalism that are most regularly described typically include attitude, competence, conduct, and perhaps above all, character – none of which, perhaps with the exception of competence, lend themselves very easily to a set of recognizable standards.Might I add, sir, that the precepts of professionalism are contained within oneself and need not be of recognizable standards, i.e., those standards are the ones you set for yourself. Recognizable by others, or not. As a former military man I'm certain you know of what I write.

[AirRabbit]

Might I add, sir, that the precepts of professionalism are contained within oneself and need not be of recognizable standards, i.e., those standards are the ones you set for yourself. Recognizable by others, or not. As a former military man I'm certain you know of what I write.
I completely agree with you, my friend – however, my point was that with respect to the components of “professionalism,” “competency” does lend itself to the application of standards (and rightfully so), but there are “standards” that just may add to the confusion with regards to some aspects of this industry’s operation. Thanks for taking the time to respond.

[rgbrock1]

Competency, as one aspect of professionalism, can indeed be measured by application of measurable and observable standards, yes indeed. I agree 100%.

[Rabski]

Connetts,

Erudite and informative, and a very good post.

However, this, and all the other sideways discussions tend to take away from the fundamental point.

Any contamination on any surface means no go.

This really is black and white and I can't believe some of the posts on this thread.

Some real insanity here. Right from my very first PPL flight, it was a given. If there is anything other than paint on the wings, it needs to be removed. Full. Bloody. Stop.

[TURIN]

M.Mouse

Your experience regarding the ground Eng and the F/O.

I have seen stand up rows on the flight deck and airbridge between flt crew, ground staff and engineer regarding de-icing. The Eng says it needs doing, the ground staff saying it will cause a delay and the Capt stuck in the middle trying to keep his job.

It's not pretty.

As you say, some employers place a different value on safety than our own.

Keep safe. :ok:

[Ice-bore]

AirRabbit wrote:

This is the underlying reason that in an earlier post I pointed out the regulatory requirement that addresses taking off with contaminants posing a safety risk, and attempted to point out why it may be that many (most?) of those pilots who seem to treat wing contamination with less respect than others … do so with confidence that governmental officials are of the opinion that only extreme cases warrant a particular response, and situations not as extreme may be disregarded and a continuation of “ops normal” may proceed. The reference is 14CFR §91.527(a) and it says, “No pilot may take off an airplane that has frost, ice, or snow adhering to any propeller, windshield, stabilizing or control surface; to a powerplant installation; or to an airspeed, altimeter, rate of climb, or flight attitude instrument system or wing…” (my emphasis added). To many, this requirement just may indicate that as long as a contaminant isn’t known to be adhering to the wing, particularly if it’s snow that has just recently fallen on the wing’s surface, it’s perfectly acceptable and certainly legal, to takeoff. The video at the start of this thread would seem to verify that there continues to be those who likely maintain this understanding and act accordingly. I’m not offering excuses … I’m suggesting that we haven’t yet done “all we can” to eliminate potentially confusing signals to those who do this job regularly.

Excellent point AirRabbit, by including the word 'adhering' the regulators are adding a degree of ambiguity to what should be a very simple and clear message here.

It's encouraging to note that the word isn't adopted in the appropriate section of EU-OPS where it states: "..A commander shall not commence take-off unless the external surfaces are clear of any deposit which might adversely affect the performance and/or controllabilty of the aeroplane, except as permitted in the Aeroplane Flight Manual.."

Basically the same requirement but less likely to lead to misinterpretation.

[lomapaseo]

including the word 'adhering' the regulators are adding a degree of ambiguity to what should be a very simple and clear message here.



Have a question about adhering ... then ask the regulator

Care to interpret it yourself then accept the violation

If it is still on your aircraft when you push back then it is adhering.

There is still room in an SOP once you depart with a clean wing. But you need to start someplace with a known degree of safety

[pigboat]

Not to worry, it'll blow off.

http://www.avcanada.ca/forums2/download/file.php?id=6208

[galaxy flyer]

Pigboat

Hope that wasn't today up on the St Larry? Sunny in YUL.

[pigboat]

No gf, I'm guessing it's in Goose Bay. It's the right company for that area. I nicked the pic from another site.

[Ocean Person]

Captain Felix Smith in his excellent autobiography " China Pilot " ( memoirs of flying in China during the civil war till 1949 ) tells how Chinese engineers would de-ice his C46 Curtis Commando during mid winter operations in northern Manchuria. They simply tossed a rope over the wing and then sawed of the ice and snow by working the rope from wing root to wing tip. It cost nothing, was quick , simply, effective and above all gave a perfectly clear upper surface and leading edge. Says heaps for Chinese know how when compared to expensive modern day de-icing methods.

Those same Chinese ground crew had their own final double check method for ensuring that onloaded fuel was not contaminated with water. So simple it's hard to believe. If anyone is interested I can pass on how they did it. Felix Smith says as Captain of the C46 he also did this just to be sure.

[Checkboard]

I have heard of "the rope trick" (either removing, or sometimes just "polishing smooth") being performed in Alaskan bush flying before.

No fair commenting on "interesting Chinese water" trick without telling what it is. :=

[stepwilk]

The rope technique is used by GA pilots in many places. Hardly a deep secret, since even I have used it.

[Minorite invisible]

This take-off would be illegal in Canada today, but only according to fairly recent regulations. Just a few years ago, it might have been legal.

Here is what the Regs say, in this part of the world anyway

No person shall conduct or attempt to conduct a take-off in an aircraft that has frost, ice or snow adhering to any of its critical surfaces.

The key word is "adhering".

That definition is the same as it was 10 years ago and is still unchanged because when an aircraft is de-iced and anti-iced and it continues to snow, by the time it begins its take-off roll, the wings may very well be covered in snow, but snow that does not adhere to the critical surfaces of the aircraft thanks to the anti-icing fluid. Before the new principles were adopted, (sept 1990 I think in Canada, following the accident report on the March 1989 Dryden accident) that same principle could be applied for dry snow: it did not "adhere".

After 1990, they had to keep the above definition but the philosophy changed, although I can't find the exact wording change in the regs they used to apply the new principles. .

When very dry snow falls on a very cold and clean aircraft (like when it's -25 Celsius on the ground) none of it sticks to the aircraft. One can blow on it and it flies off, leaving no trace on the surface of the aircraft. Back in those days, our spoilers were painted black. When we wanted to ascertain that our aircraft was "clean", one pilot would walk back in the cabin and look at the wings while the pilot remaining in the cockpit would raise the spoilers. If the spoilers were clean and free of snow while in the vertical position, we could take off, if not we would have to de-ice. They were painted black so that any snow or ice would stick out.

Russia is now where Canada was in August 1990 and everyone acts as though it was never done in these parts of the world.........

Here is a picture of such an aircraft with a black spoiler.......

https://lh3.googleusercontent.com/-KBl162TS464/T5Fjve2oQWI/AAAAAAAAJxM/LvRZaxroGrw/w294-h197-k/spoiler.jpg

[Ocean Person]

Checkboard;

My apology, just did not want to appear to know all. The procedure used as described by Captain Smith was to catch a few drops of fuel in the cupped palm of one hand and then gently blow on the fuel to cause some evaporation. If evaporation did not occurr then the liquid was water.
" China Pilot" is a very special book. It's a book written in pilots' language that only a fellow pilot can fully understand. An example is when converting onto the C119 Felix said of the stall sequence " I shoved the nose down and the power up and tucked the sounds and feeling into my memory " It's the flying life of a soldier of fortune who upon retirement back to the USA said " the world is flat after life in asia " Michael Collins of Apollo 11 said "China Pilot " is a wonderfull book. Buy it and give yourself a treat, at the moment Amazon Books have 5 copies in stock.

[Ice-bore]

That definition is the same as it was 10 years ago and is still unchanged because when an aircraft is de-iced and anti-iced and it continues to snow, by the time it begins its take-off roll, the wings may very well be covered in snow, but snow that does not adhere to the critical surfaces of the aircraft thanks to the anti-icing fluid.

This is a totally incorrect and misleading statement which, in my opinion, should be removed before the less well informed start to believe it's true..!!

The glycol present in the anti-icing fluid will effectively melt the snow falling on it and the fluid will become progressively more and more diluted as time passes. Eventually the glycol will be diluted to a level where it becomes totally ineffective and the snow will start to form or accumulate on the treated surfaces. At this time the so called 'Holdover Time' will have run out and the aircraft will require a further de-icing/anti-icing treatment.

While under certain conditions any anti-icing fluid residues remaining in contact with the structure may prevent the accumulating snow from bonding or freezing to the surface of the aircraft, there is no guarantee of this and certainly no guarantee that this partially melted snow will effectively flow off on any anti-icing fluid residues that may be still present.

To quote from Section 3.15 in Edition 26 of the AEA Recommendations for De-icing/Anti-icing Aeroplanes on the Ground, "..Holdover time will have effectively run out when when frozen deposits start to form/accumulate on treated aeroplane surfaces.." At this time a further de-icing/anti-icing treatment would of course be required.

[ManaAdaSystem]

This is a totally incorrect and misleading statement which, in my opinion, should be removed before the less well informed start to believe it's true..!!

Thank you, Ice-bore! It's really surprising how little fellow pilots (?) understand when it comes to this subject. Or maybe scary is the correct word?

[lomapaseo]

Thank you, Ice-bore! It's really surprising how little fellow pilots (?) understand when it comes to this subject. Or maybe scary is the correct word?

but to me the way to address the problem are the SOPs, being approved by a regulator, and monitored by the Operator. We can't afford to make all pilots believe, but we can try better to make them "adhere"

[Minorite invisible]

The glycol present in the anti-icing fluid will effectively melt the snow falling on it and the fluid will become progressively more and more diluted as time passes. Eventually the glycol will be diluted to a level where it becomes totally ineffective and the snow will start to form or accumulate on the treated surfaces. At this time the so called 'Holdover Time' will have run out and the aircraft will require a further de-icing/anti-icing treatment.

Are you claiming that when an aircraft takes off during snow showers and within the allowed hold-over time, thanks to the magical effect of glycol, the snow instantly turns into water and the wings just look wet, as though it was just raining? There is no presence of slush, partially melted snow, snow crystals, nothing that has consistence?

In fact there is, and that is why the Regs, here anyway, still allow take-off as long as none of that stuff adheres to the surfaces.......

[AirRabbit]

First issue with QH90 was very primitive (but legal at the time) FDR, which did not record attitude or power. In AirRabbit's alternative view on the accident, holes left by primitive recording equipment are filled by conjecture
Of course anyone here is free to offer their opinions ... but what I have offered is not “conjecture” any more than it is questioning the conclusions reached based on the information gathered ... as differentiated from the material eventually included in the official Accident Report. So, let’s look at facts and questions ... and let the reader come up with his/her own “conjecture.”

Fact: According to the Accident Report, the Trump De-Icing Vehicle did not incorporate the “mix-monitor” which allows the operator to ascertain that the desired mixture is indeed being delivered at the nozzle.

The Trump De-Icing Vehicle used to deice/anti-ice the accident airplane had recent “repairs” completed that resulted in the nozzle dispensing fluid at 18 percent glycol mixture from the deicing wand at a minimal flow rate, but when the operator increased the flow rate, all of the additional volume flow came from the heated water tank, and none from the glycol tank – effectively lowering the solution percentage by an unknown but substantial proportion, potentially reaching a solution of “zero glycol” being dispensed.

Question: Why is it that this information was not included in the Accident Report?

Answer: Up to you.

Question: Could the deicing/anti-icing solution provided by this “repaired” deicing vehicle, in combination with the ambient temperature of 24F, applied to a “cold-soaked” airplane, have had any effect on whether or not ice could accumulate on the aircraft? Could this solution, in combination with any potential snow fall, have had any effect on whether or not ice could accumulate on the aircraft?

Answer: Up to you.

It's easy for some to suggest that wing contamination might have played a part (after all the evidence melts immediately after a crash).
However the validated contributions are covered in the NTSB report hence the recommendations regarding engine power set "check'.
The Forum thread we are burried within is an equally important opportunity thread to discuss wing ice as a prime consideration on its own without mixing it up in a controversial message about Air Florida in the Potomac

Fact: Of course a snow-covered or an ice-covered wing would not be recovered from the Potomac. That is precisely why it is important to understand just how the deicing and anti-icing of the airplane took place – at least as important as knowing what snow actually fell between that process and the takeoff. All 3 aircraft (the accident aircraft, the aircraft preceding and the aircraft following) were in the same line for takeoff on the same runway. All 3 aircraft were exposed to the same weather conditions (including snow fall) for the same length of time.

Question: Why would only one of those aircraft (the one in the middle) have had a problem?

Answer: Up to you.


The first of the 3 causes of the accident, cited by the Accident Report:
“...the flightcrew’s failure to use engine anti -ice during ground operation and takeoff...”

Fact: The CVR transcript shows that during the “after start” checklist (which was conducted as a challenge/response exercise) at the F/O’s challenge (reading the checklist) item “Anti-ice” (referring to the engine anti-icing switches) the response, provided by the Captain, is indicated as “OFF,” and is shown within parentheses. The legend for the CVR shows that any transcript content contained within parentheses indicates “questionable text.”

Question: In that there are only two positions for those switches, either “ON” or “OFF,” when the response, as recorded on the cockpit voice recording tape, is not clear, why was “OFF” chosen to be placed within those parentheses instead of the only other alternative, “ON”? This is the only indication that engine anti-ice was not used. If the actual recording is not clear, and there are only 2 choices – why was “OFF” determined to be the response that should be included within those parentheses, instead of “ON”?

Answer: Up to you.

(Information: Just in case anyone may be interested ... when the wreckage of the airplane was retrieved, the position of the switches on the overhead panel and the position of each of the 3 associated valves in each of the engines were inconclusive – which is not uncommon for the amount of impact destruction experienced.)


The second of the 3 causes of the accident, cited by the Accident Report:
“...their decision to take off with snow/ice on the airfoil surfaces of the aircraft...”

Fact: for that day, the recorded information regarding snow fall was as follows...
Moderate snow began at 1240 and ended at 1320.
Heavy snow began at 1320 and ended at 1525.
Moderate snow began at 1525 and ended at 1540.
Light snow began at 1540 and ended at 1553.
Moderate snow began at 1553 and ended at 1616.

Again, the airplane preceding and the airplane following the accident B-737 were subjected to the same processes and weather prior to takeoff.

Question: If it was the snow fall that accumulated on the B-737 between the gate and their takeoff that caused the accident – what prevented the other two airplanes from suffering the same fate?

Answer: Up to you.


The third of the 3 causes of the accident, cited by the Accident Report:
“...the captain’s failure to reject the takeoff during the early stage when his attention was called to anomalous engine instrument readings.”

Fact: The first time the F/O expressed anything that sounded like he was questioning something was at 1600:02 when he said, “That don’t seem right does it?” This was followed at 1600:05 by “Ah, that’s not right” and then an inaudible comment, followed by the Captain saying “Yes it is, there’s eighty” at 1600:09. Then at 1600:10 the F/O said “Naw, I don’t think that’s right, followed at 1600:19 with “Ah, maybe it is.” Two seconds later, at 1600:21, the Captain says “Hundred and twenty.” Then the F/O says “I don’t know.”

Observation: The committee that listened to the actual CVR recording apparently concluded that the F/O was expressing a concern over an “engine anomaly,” and of course, that is certainly a possibility. For almost 20 seconds it would appear that both the Captain and the F/O were attempting to recognize something in the cockpit that was causing the F/O to make the comments he made – apparently without being able to identify what that was.

Question: What would have been anomalous to the F/O and not to the Captain? Would this be the only thing that would have caused the F/O to make the comments he made?

Answer: Up to you.

Fact: A landing airplane was on final when the accident B-737 was cleared into position and cleared for takeoff. Approximately 20 seconds elapsed from the time the tower advised that there was a landing airplane on final at 2 and ½ miles behind the departing B-737 (at 1559:28) to the time the CVR recorded the sound of the engines spooling up toward the desired takeoff setting (at 1559:48). Another 14 seconds had passed when the F/O first indicated that there was something that he thought didn’t “seem right” (at 1600:02). Another 7 seconds had passed when the Captain noted that the B-737 had reached 80 knots (at 1600:09).

Question: How far behind the B-737 was the landing aircraft at these points?

Answer: Up to you.

Fact: At 1600:11 the landing aircraft called, “Fourteen fifty-one, cleared to land over the lights” (which extended 2400 from the runway’s threshold). We do not know the specific point over those approach lights the landing B-727 actually was at the time of that radio call.

Question: At this point, how far behind the B-737 was the landing aircraft?

Answer: Up to you.

Question: Would you have aborted the takeoff?

Answer: Up to you.


Fact: The accident report states “there were other incidents similar to this one reported, in which the crew was able to overcome the contamination, but they needed the proper thrust level of 2.04 EPR.” On the same day as the Air Florida accident, another B-737 attempted a takeoff out of Oslo, Norway, where the taxi and takeoff were conducted during a snowstorm. During the takeoff, as the crew began to rotate, the airplane pitched-up and due to the asymmetry of the deformity of the wings, began a roll. Neither the pitch nor the roll was controllable by the crew. Even though the throttles were “slammed” to the firewall immediately and the fact that the pilot used full opposite aileron and full opposite rudder, the pitch and roll of the aircraft was not controllable. Apparently, due to the radical bank angle reached (approaching 90 degrees), the nose dropped back down toward the horizon, and with the throttles fully forward, the airplane began to accelerate. As the acceleration continued, apparently lift was produced over the outboard portions of the wing, including the ailerons, and the crew was able to roll back to level flight. The crew recovered the airplane; but that recovery was below 100 feet above the ground.

Question: Why were the only incidents of B-737 pitch-up and/or roll-off described in the Accident Report those that were recoverable?

Answer: Up to you.


Have a question about adhering ... then ask the regulator
Care to interpret it yourself then accept the violation
If it is still on your aircraft when you push back then it is adhering.
There is still room in an SOP once you depart with a clean wing. But you need to start someplace with a known degree of safety
My first inclination is to say “from your lips to the hearts and minds of aviators everywhere.” However, I am mindful of the fact that most of those aviators are heavily influenced by all sorts of external factors – their boss, their job, their salary, etc. Most of these external factors have a tendency to influence the way individuals interpret specific issues to result in the most advantageous and to the least negative impact possible. To that end, I’m taken back to the simple fact that the FAA has maintained that the only time they feel it necessary to specifically define a word that they use in their regulatory documents is when the definition they desire to use is either not included in the dictionary or the dictionary definition is not the meaning the FAA wished to convey. Terms that are used in the regulations are either defined in the regulations (some place) or they rely on the traditional understanding (i.e., dictionary definition) of the term. Since the term “adhering” is not found in the regulations – in those parts or sections were there are requirements laid out for taking off or landing in inclement weather conditions or in their primary rule dealing with definitions, the only definition that can be applied to this term is the definition found in the dictionary. According to Merriam-Webster, the term “adhere” means (in the context used in these rule sections) “...to hold fast, or to stick through gluing, suction, grasping, or fusing.”

As long as the rule uses that term, I think we all have to recognize that there is likely to be a substantial number of people who will find that definition to be a way to continue operations when that continuation may not be the most conservative decision.

[Rabski]

"I am mindful of the fact that most of those aviators are heavily influenced by all sorts of external factors – their boss, their job, their salary, etc."


reading through the thread, I worry that I might be in the minority. When I fly, I have two primary considerations: my safety, and that of the passengers behind me.

If those considerations don't suit my boss, then I will soon be bossless. However, in my minimal experience, my bosses have been on the same channel. Even if only because a mighty screw up is going to cost them big time.

As before. Contamination on any surface = no fly. End of.

If any boss doesn't like that, then that's tough. Stuck up the pointy end, it's my responsibility and I take that seriously, not least because my a**e is equally on the line.

[AirRabbit]

reading through the thread, I worry that I might be in the minority. When I fly, I have two primary considerations: my safety, and that of the passengers behind me...
...and if I ran my own airline, you would be the kind of person I would hire! I believe in the tried-n-true adage ...”you think training is expensive, try an accident!” Unfortunately not all airline owners, managers, etc. believe as you do ... and even more unfortunately, there are far too many young and eager, still “damp” behind the ears, fledgling pilots that will take what they can get because they believe that’s all they will be offered. I’m with you, my friend, I’d rather sell cars, mow lawns, bag groceries, whatever ... and still be here to take care of my family. Death is a rather permanent state that I’d like to avoid for as long as possible.

[Elastoboy]

Not wanting to hijack the thread (mods please move it if you like)
Monday 16th flew from an Alberta location to one in Texas - Flew commercial as the company units were busy. Pushed back at 10 mins late 07:10. The aircraft had been at gate for over 8 hours over night and the temps were all below freezing, but no precip in the preceeding 12 hours.
Promptly taxied past all the WestJet aircraft being de-iced and lined up and rolled - needless to say studied stbd wing very closely to see any signs of ice, but it did appear clean.
If the locals de-ice all their overnighting aircraft, why not the legacy US carrier?

[Ice-bore]

Are you claiming that when an aircraft takes off during snow showers and within the allowed hold-over time, thanks to the magical effect of glycol, the snow instantly turns into water and the wings just look wet, as though it was just raining? There is no presence of slush, partially melted snow, snow crystals, nothing that has consistence?

Yes, where the aircraft has been anti-iced with a Type II or IV fluid. I'm not a chemist but I believe this takes place due to chemical action rather than magic.

Due to the thickening agent present in Type II and IV de-icing/anti-icing fluids these fluids are able to remain on and protect aircraft surfaces for a period of time (see holdover time tables for applicable times).

As the snow flakes impinge on the fluid film they melt, due to the low FP of the glycol in the fluid, progressively diluting the fluid and yes the surface does look wet at this stage. Depending on the intensity of the snowfall it may take a few seconds for the individual snow flakes to melt but once slush or snow is seen to be building up on the fluid film the holdover time will have expired and a further treatment will be required.

The viscosity of the fluid is relatively high when applied to the surfaces of an aircraft on the ground, however, as the aircraft accelerates during take-off the shearing effect of the airflow over the wings breaks down the structure of the fluid, reducing the viscosity and allowing it to flow off to provide a clean wing. Clearly if the fluid film has snow on top of it, it will be prevented from working as designed.



In fact there is, and that is why the Regs, here anyway, still allow take-off as long as none of that stuff adheres to the surfaces.......

It would be appreciated if you could let us know where, in your regulations, it allows you to take-off with snow/slush present on top of an applied film of anti-icing fluid...

[CONF iture]

Ice-bore is correct.
Extract from a Ground Icing Ops Manual :
Aircraft surfaces treated with de/anti-icing fluid should appear glossy, smooth and wet, if not, the fluid is no longer effective.

[Minorite invisible]

It would be appreciated if you could let us know where, in your regulations, it allows you to take-off with snow/slush present on top of an applied film of anti-icing fluid...

In a non-regulatory document called
TP 10643 - When in Doubt... - Transport Canada (http://www.tc.gc.ca/eng/civilaviation/publications/tp10643-menu-1118.htm)

in paragraph 77

Frost, ice or snow on top of deicing or anti-icing fluids must be considered as adhering to the aircraft and take-off must not be attempted.

My company MANOPS also says:

Aircraft surfaces treated with de/anti-icing fluid should appear glossy, smooth and wet, if not, the fluid is no longer effective.
Some indications of loss of fluid effectiveness are:
- Progressive surface freezing (loss of wetness);
- Random accumulation, i.e. snow flakes remain on the fluid surface without melting;
- Snow accumulation;
- Dulling of surface reflectiveness (loss of gloss);
- Foggy fluid appearance (gradual deterioration of the fluid to slush); or
- Ice pellets precipitation is susceptible to degrade the de/anti-icing fluid very rapidly. It is believed that ice pellets are capable of penetrating the fluid and have enough momentum to contact the aircraft’s surface beneath the fluid. A local dilution of the fluid by the ice pellet would result in the vey rapid failure of the fluid.
If the de/anti-icing fluid exhibits one of more of the preceding indications, the aircraft must be considered contaminated.


But the law in Canada is the Canadian Aviation Regulations, part 602.11

Part VI - General Operating and Flight Rules - Transport Canada (http://www.tc.gc.ca/eng/civilaviation/regserv/cars/part6-602-2436.htm)


(2) No person shall conduct or attempt to conduct a take-off in an aircraft that has frost, ice or snow adhering to any of its critical surfaces.

(4) Where conditions are such that frost, ice or snow may reasonably be expected to adhere to the aircraft, no person shall conduct or attempt to conduct a take-off in an aircraft unless

(a) for aircraft that are not operated under Subpart 5 of Part VII (meaning commercial non-airline),

(i) the aircraft has been inspected immediately prior to take-off to determine whether any frost, ice or snow is adhering to any of its critical surfaces, or

(ii) the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program; and

(b) for aircraft that are operated under Subpart 5 of Part VII (airliners), the operator has established an aircraft inspection program in accordance with the Operating and Flight Rules Standards, and the dispatch and take-off of the aircraft are in accordance with that program.

(5) The inspection referred to in subparagraph (4)(a)(i) shall be performed by

(a) the pilot-in-command;

(b) a flight crew member of the aircraft who is designated by the pilot-in-command; or

(c) a person, other than a person referred to in paragraph (a) or (b), who

(i) is designated by the operator of the aircraft, and

(ii) has successfully completed an aircraft surface contamination training program pursuant to Subpart 4 or Part VII.

(6) Where, before commencing take-off, a crew member of an aircraft observes that there is frost, ice or snow adhering to the wings of the aircraft, the crew member shall immediately report that observation to the pilot-in-command, and the pilot-in-command or a flight crew member designated by the pilot-in-command shall inspect the wings of the aircraft before take-off.


Notice that the word "adhere" is always there, when the law could have been written with the exact same wording but with the word "present" instead of "adhere". Why ?

[lomapaseo]

Notice that the word "adhere" is always there, when the law could have been written with the exact same wording but with the word "present" instead of "adhere". Why ?


"present"

Like blowing snow across a cold flat surface that does not accumulate on such surface

"adhere"

Where it does accumulate

If you start your taxi (after dispatch) and the snow has already accumulated on the wing even in patches, it has "adhered" and you should be in violation of a hard rule if you dispatched that way.

A clean wing/engine etc, at dispatch, that subsequently accumulates snow or ice falls under a different operational SOP (one that minimizes the effect)

A wing/engine that accumulates ice in the air falls under a design regulation as well as an operational SOP

[Cagedh]

to adhere (source (http://dictionary.reference.com/browse/adhere))
verb (used without object)
1. to stay attached; stick fast; cleave; cling (usually followed by to ): The mud adhered to his shoes.

[AirRabbit]

If you start your taxi (after dispatch) and the snow has already accumulated on the wing even in patches, it has "adhered" and you should be in violation of a hard rule if you dispatched that way.

The problem is the use of language … and I don’t necessarily limit that to the use of the English language. All languages present its users with some difficulty in expressing exactly what is meant. That’s why language is described as consisting of 3 parts: what is said, what is heard, and what is meant. Of course when snow is “blowing” across a surface it doesn’t “accumulate” on that surface. But I think anyone would be hard-pressed to say that simply because snow has “accumulated” on a surface, that it has also “adhered” to that surface.

There are a lot of the Canadian rules that are quite direct and to the point and would probably be preferred by most aviators – given the chance … but even then, the language our friends in Canada use can present the same sort of understanding or interpretation questions. For example the Canadian rule quoted as saying “…conditions are such that frost, ice or snow may reasonably be expected to adhere to the aircraft…” Then the question becomes, what is “reasonable?” Does “expected” mean that it is suspicioned to have adhered already, or will, within a short time in the future, begin to adhere? If it is expected in the future, what time frame would be acceptable – or – how short is short? Or, do we throw it all in the air and let the lawyers figure it out?

Using the word “accumulate” doesn’t necessarily solve these issues either. If any rule was changed to say takeoff must not be attempted when ice or snow has accumulated on the wing … then virtually any snow fall would prevent virtually any taxi time between “deicing” and “takeoff”. Anyone who has taxied from a gate to a runway for takeoff when snow was falling, can easily attest to the fact that “some” snow accumulated on the wings prior to taking off. If the parameters of such an accumulation cannot be clearly articulated and then adequately communicated, then, the conversation between the two Air Florida pilots becomes a lot more prophetic …

Captain: Right there is where the icing truck…they oughta have two of them, you pull right…
F/O: …right out
Captain: Like cattle … like cows right.
Captain: Right in between these things and then…
F.O: …get your position back
Captain: Now you're cleared for takeoff
F/O: Yeah and you taxi through … kinda like a car wash or something
Captain: Yeah

I know there are some airports who use precisely this method … and I would presume that there have been very few, if any, takeoff incidents attributed to ice or snow presence, accumulation, or adherence at those airports. The problem with this method is one of expense … both initial and maintenance … and then there is always going to be the environmentalists that would need to be satisfied with respect where the runoff would be captured and disposed of properly.

:hmm: Ahhh … the simple life of an aviator …

[no expert]

I note a few references to the crash of Air Ontario Flight 1363, a Fokker F28 which crashed into a forest less than a kilometer from the end of the runway at Dryden Ontario in 1989. The accident resulted in 24 fatalities, including both of the flight deck crew and the senior flight attendant. There were 45 survivors, including a second flight attendant.

Subsequent to the accident and the official accident report the government formed a Commission of Inquiry chaired by the Honourable Vincent Mashansky to examine not just the immediate cause of the accident (which was unquestionably the decision of the pilot to depart the runway with snow-contaminated wings) but also all of the causal factors which may have influenced the captain’s unfortunate decision to attempt the takeoff, given that he had a reputation for being cautious and responsible (although this may have contributed to his decision, inasmuch as he no doubt also felt a responsibility to get his passengers to their destination, particularly as it was the start of a school break and many passengers were to connect to flights which would take them to vacation destinations).

Justice Mashansky’s 1,300 page report is very comprehensive. It could serve as a textbook example of how all of the holes can line up, insofar as the Commission found that virtually everyone having anything to do with Flight 1363 and this aircraft made errors or omissions which individually might be deemed insignificant but collectively led to a smoking hole in the ground. (To be clear, the interpretation that the errors might be deemed insignificant is mine alone… Mashansky was less forgiving). These factors included the ground worker who fueled the craft but failed to bring the snow on the wing to the captain’s attention, and the senior flight attendant who dismissed the concerns expressed by a nervous passenger, as well as the junior attendant who deferred to the judgement and authority of her senior colleague.

Perhaps most relevant to this discussion the Commission examined the responses of two surviving passengers… an off-duty Air Ontario Dash 8 captain and an off-duty Air Canada DC9 captain. One of these testified that he knew that the aircraft would not fly (emphasis mine) but presumed that the captain knew this too. In any case, he testified that he presumed that the captain planned to monitor the snow on the wings during the takeoff roll and would abort the takeoff once he saw that the snow was adhering to the wing. According to the testimony of others this method of determining wing contamination during the takeoff roll was not entirely uncommon at Air Ontario (which had evolved from Austin Airways, flying DC3 and Otters around northern Canada) and if I recall correctly Justice Mashansky (a pilot himself) found this practice to be unsatisfactory to say the least. We can be certain that the regulations drafted subsequent to this accident were not intended to allow pilots to make their determination of whether snow and ice were “adhering” when they were halfway down the runway approaching V1.

It’s nice to see that many on this board say that they would have… had they been passengers… prevented the takeoff attempt. However, in this context it ought to be noted that the other off-duty captain was also aware of the condition of the wing, but felt that professional courtesy and respect required that he remain silent. The two passenger-pilots had something like 18,000 hours experience between them while the two at the pointy end had something like 130 hours of combined experience (on type).

I recognize that this report is now twenty years old and we now have a greater appreciation of human dynamics (if only because of subsequent incidents and accidents). Taken as a whole the report was (and remains) a damning indictment of the airline`s owners and managers (largely one and the same) and Air Canada (Air Ontario`s code-share partner and part-owner at the time). Ultimately, of course, the report infers that industry deregulation in the absence of adequate regulatory authority created an environment which contributed to the accident. Mashansky made 191 recommendations, and while I believe that some were acted upon I’ve a hunch that most were not. Indeed, something like 18 months after the release of the report another F28 (USAir 405) crashed at LaGuardia under similar circumstances.

I presume, of course, that I am preaching to the choir here. In fact, I hope that I am.

And I apologize to those who I've offended, given that... well, my username says much. Indeed, I was going to keep my thoughts to myself until I realized that I am one of those people who would keep my thoughts to myself even if there was a foot of snow on a wing.

Apologies for being so long-winded, and mods feel free to edit.

The full text of the report can be found here:

Commissions of Inquiry (http://epe.lac-bac.gc.ca/100/200/301/pco-bcp/commissions-ef/moshansky1992-eng/moshansky1992-eng.htm)

Also, there is an episode of “Air Crash Investigation” devoted to the accident and Mashanky’s report here:

Air Crash Investigation - Snowbound / Cold Case / Unwelcome Addition (S09E06) - YouTube

[DOVES]

I wrote:
Let me add that after that accident some woolen threads were installed at the roots of the wings of the MD80, free to shake into the wind, in order to facilitate the identification of subtle icing Vetrone by the crew, often unnoticed.


Mostly correct but they were not put there to depend on the wind for visualization. They required movement by a pole device held by a man on a ladder. If you couldn't move them they were probably covered by a film of ice.


I am grateful for correcting me.
As a matter of fact I remember that we were expected to perform a visual inspection of the tuft on the upper surface of the wings from the cabin, in case of doubt we had to open the wing emergency exit, go out and touch the surface to ensure that there was no ice.

The biggest problem with the dispatch with wing ice was the first flight of the day after an overnight in drizzle/snow. The snow would be blown off on the ground but they missed the check underneath for ice

As we all know there’s a phenomenon called cold-soaked fuel, which happens if the aircraft is parked with wing tanks not completely filled with fuel, which then evaporates. This gas expansion reduces the temperature, and so even if the outside air temperature does not fall below zero, the moisture in the air condenses and then freezes in contact with the sheet of the wing. During the walk around a 3 mm layer of frost was acceptable below the wing corresponding with the tanks.
It seems that those ice formations, resulting from the cold soaked fuel, broke during take off, causing both engine flame out which determined the crash of the MD-81 SAS in Gottrora on December 27, 1991.


Contrary to popular belief there were only a few incidents of ice due to cold soaked fuel in above freezing conditions.


So why, before their production was discontinued, a plan has been made to install de-icing panels at the root of the wings of MD 90/Boeing MD 717?

AirRabbit:
It's really moving the ardor with which you defend the actions of the crew of Air Florida Flight 90 which crashed into the Potomac January 13, 1982.
Many wise philosophers in ancient Greece argued that we should defend a friend by all means also we know he's guilty.
Nevertheless you will agree with me that the following illegalities were committed:
- They did not insert Engine Anti-ice after start, and did perform the periodic engine run up.
- They tried invain to push back (the tug connected) through the use of reverse (thus raising clouds of snow and slush).
- They knew they had snow on the wings, so that they approached the preceding DC9, in the vain hope that their jet engines would swept it away.
- They started the take off run 50 minutes after the de-icing.
- They accepted a very little separation with the landing traffic despite the poor visibility and the snow storm. (If they had to abort the takeoff? If the others were to go around?)
- They underestimated the irregularity of the engines parameters for takeoff
- They had found that the acceleration was so poor that they had reached 120 knots after 45 seconds.
- They began to rotate as per “the soft field” (I began to hear such an expression only since I'm instructing in general aviation) and then starting the rotation well before Vr.
I'm sorry but I have to tell you that History has been written.
So much time and money has been spent to establish the causes of the disaster, so justice was done and the incident would had never happened again (sic!).
So unless you have any new evidence to reopen the trial, agree with NTSB.
Let’s shout together:
“How can you know if any kind of snow is ‘ADHERING’ to the surfaces of your airplane, and no ice is beneath it, if you don’t remove it?”
“No clean aircraft? No Fly!”

Here you are Lomapaseo.
Is this the way you like it?

[lomapaseo]

Doves

If you intend to use quotes, then please use the quote function

If you have questions by all means use a question mark

If you have already concluded something, then don't atempt to intermix your opinion being supported by somebody elses quote.

I really can't sort out which is which in your post above

[AirRabbit]

It's really moving the ardor with which you defend the actions of the crew of Air Florida Flight 90 which crashed into the Potomac January 13, 1982.
Nevertheless you will agree with me that the following illegalities were committed:
I will be more than happy to “agree” with you when you post something that is accurate. I’ve often said that I’m not writing to defend the flight crew. They certainly made errors. However, the errors they made did not cause the accident. I’ve been quite clear about what, in my sometimes not-so-humble-opinion, it was that actually caused this particular accident … it was the exact same thing that almost caused the B-737 to crash in Oslo, Norway on that same day, January 13, 1982.

They did not insert Engine Anti-ice after start, and did perform the periodic engine run up.
The only place that indicates the flight crew did not use engine anti-ice is the CVR and transcript thereof … as I’ve pointed out earlier … that transcript clearly shows the response to the challenge-response checklist item “Anti-ice?” was recorded and published as “(OFF)” … and you will note the presence of parentheses around the word. If you had bothered to check what those parentheses meant, you would have found that they mean “questionable text.” In other words the committee that was listening to the actual CVR were not able to determine what was said to that particular checklist challenge item. The fact is that choosing to have the transcript show that response as “(ON)” should have been just as valid as having the transcript read the way it does. In that there are only two positions in which those switches could have been placed, those being either OFF or ON, when you cannot determine what was said – and the transcript is presented the way it is presented to show the reader that the response is UNKNOWN – how do YOU know that what was chosen to be placed on the transcript was, in fact, the actual position of those switches?
They tried invain to push back (the tug connected) through the use of reverse (thus raising clouds of snow and slush).
No. The crew did not attempt to use reverse thrust to push back. The practice was apparently to start the engines at the gate, and then push back. This was attempted, but the tug being used was unable to acquire sufficient traction to push back the airplane, particularly “up” the slight incline that existed at that gate (see the accident report). Recall, the airplane had just been “deiced” and as a result the ramp around the airplane – which also had been subjected to prolonged sub-freezing temperatures – and because the Trump deicing vehicle was improperly repaired and was not functioning properly, a fairly extensive amount of water was sprayed all over it, very likely resulting in a much greater than anticipated accumulation of ice – making the traction available to the tug to be much less than normal. Additionally, as I’m sure you are likely knowledgeable of such things, engines at idle thrust still produce a forward thrust component – and the ground crew, the tug driver, and the flight crew attempted to neutralize this forward thrust component by opening the thrust reversers while keeping the throttles in the idle position. Again, the tug attempted to push back … and, again, was unsuccessful. The decision was made to shut down the aircraft engines and obtain a larger, heavier tug, one equipped with tire chains to attempt the push-back. This was accomplished. After the push-back was completed, the crew again started the engines. Here’s the quote from the Accident Report:
“Witnesses estimated that both engines were operated in reverse thrust for a period of 30 to 90 seconds. During this time, several Air Florida and American Airlines personnel observed snow and/or slush being blown toward the front of the aircraft. One witness stated that he saw water swirling at the base of the left (No. 1) engine inlet. Several Air Florida personnel stated that they saw an area of snow on the ground melted around the left engine for a radius ranging, from 6 to 15 feet. No one observed a similar melted area under the right (No. 2) engine.
Note that there is no indication of “raising clouds of snow and slush” as you’ve indicated.
They knew they had snow on the wings, so that they approached the preceding DC9, in the vain hope that their jet engines would swept it away.
Undoubtedly, you are referring to a single comment made between the pilots during their lengthy taxi process, and you have determined that the description of what was happening was as a result of a determined effort of the pilots. There were a total of 2 comments to which you may be referring:
1. (1546:21)
“Tell you what, my windshield will be deiced' don't know about my wing”

2. (1551:54)
“Don't do that Apple, I need to get the other wing done ((sound of laughter)).”

In the first example, if you are at all familiar with the taxi process from the ramp to what was then Runway 36 (now Runway 1) you know it involves crossing runway 3 (now runway 4). In that the accident airplane was following behind a New York Air DC-9, when that DC-9 added power to cross that runway, given where the DC-9 engines are mounted and the fact that even more engine thrust would be needed to climb the slight incline to cross the runway than would be needed to begin taxiing again, it is likely that the thrust encountered by the accident airplane was noticeably more, and that thrust was commented on by the Captain who could just as easily – and very likely – meant it as a satirical comment – just as you might say – “just my lucky day” when you find out from your operations that the airplane you’re changing to when at JFK is on the other side of the airport!

In the second example, and again, as you may already know, the waiting area between runway 3 and runway 36 is a larger area where airplanes can wait without blocking access to the entrance to runway 36, and most airplanes park in that space angled away from blowing exhaust directly on the airplane behind them in line. However, when an airplane begins to move – either to move up to the next space in that waiting area or to taxi onto the runway, additional thrust is used, and through the turn, blows all that additional exhaust directly on the airplane waiting in that area. Additionally, as the end of that comment there are the words “sound of laughter,” indicating that the flight crew was commenting in a jocular (or frivolous) manner – indicating to many readers that the flight crew was not very serious about their jobs – I’ll call your attention, once again, to the fact that even the committee who listened intently, very likely for hours, still could not determine exactly what was recorded on the CVR, and that is why those words are contained in those parentheses.
They started the take off run 50 minutes after the de-icing.
…just as did Apple 58, taking off immediately prior to the accident airplane, AND as did Six Eight Gulf, taking off immediately after the accident airplane.
They accepted a very little separation with the landing traffic despite the poor visibility and the snow storm. (If they had to abort the takeoff? If the others were to go around?)
They did, indeed, accept the clearance onto the runway to hold (1558:58) … they also accepted the takeoff clearance (1559:24) – even acknowledged it (1559:26) – almost a full 30 seconds after they were cleared onto the runway to hold … but they were not advised of the position of the landing traffic until the next radio call from the tower (1559:28) advising them that landing traffic was “two and a half out for the runway.” Of course, as, again, you would also know, when the visibility is as low as it was that day – putting the responsibility on the flight crew for visually checking final for landing aircraft is a bit much … as the only folks who know about that sort of information are the guys in the tower … who apparently didn’t think that this day presented anything different from the way they regularly moved traffic at that airport.
They underestimated the irregularity of the engines parameters for takeoff
How do you know if there was an irregularity, or if there was one, how do you know that they actually saw what it might have been? The investigators presume that the questions the F/O had raised were because of an engine anomaly – but for a full 20 seconds after the F/O’s first question, neither he or the Captain could find anything that they thought might be “anomalous” with the engines – at least neither of them said anything or did anything that indicated they recognized anything out of the ordinary.
They had found that the acceleration was so poor that they had reached 120 knots after 45 seconds.
Really? 45 seconds after what? As for the acceleration rate ... it may have been the fact that they both were attempting to find what it was that caused the F/O to ask the first question that they didn’t notice the acceleration rate – or it may have been that they had very little outside cues (due to the very limited visibility) with which to make a speed change observation and it was that fact that prevented them from assessing anything about the acceleration.
They began to rotate as per “the soft field” (I began to hear such an expression only since I'm instructing in general aviation) and then starting the rotation well before Vr.
To show that this statement is in error, all you have to do is read the CVR transcript. The V-speeds were briefed to be V1 = 138 knots, VR = 140 knots, and V2 = 144 knots. The CVR transcript also shows that the Captain calls out “Vee One” (1600:31) and then 2 seconds later calls out “Easy.” There are many professional aviators who sincerely believe that the comment “Easy” was in response to what appeared to be a very quick rotation (likely occuring when the F/O began his rotation, precisely at VR speed) – and then subsequently learning about the B-737’s tendencies to rotate rather quickly and with some force when the wings were contaminated with a very small amount of contaminants. Then some 5 seconds after that (1600:37) the Captain calls out “Vee Two.”
I'm sorry but I have to tell you that History has been written.
Well, at least someone’s version of history was written, that is for sure. But I think that the conclusions reached were at least as much for expediency as anything else. I am certainly not going to generate accusations that might get me or this forum into trouble … because what we are discussing was, indeed, 30 years ago. Also, there has been a lot of education that has taken place as a result of all the discussions centered around this particular accident – which, as anyone should recognize, is a good thing. But, and as I’ve said several times now on this thread, my intent here is not intended to impugn the fine reputation or the integrity of the NTSB or of the dedicated and professional employees at the Safety Board. If someone else desires to determine who or what may have been either hurt or benefited from another “version of history” being written – let them have at it. My only motive has been a continuing effort to describe the actions of the flight crew from a slightly different perspective while providing what I believe to be clarifying information regarding the cause of the accident and, to the best I am able, set the record straight– as much as one can this long after the fact.

[DOVES]

I will reply later point by point.
But, what about:
Let’s shout together: “HOW CAN YOU KNOW IF ANY KIND OF SNOW IS ‘ADHERING’ TO THE SURFACES OF YOUR AIRPLANE, AND NO ICE IS BENEATH IT, IF YOU DON'T REMOVE IT?”
“No clean aircraft? No Fly!”
Which is at the root of this thread.

[Island-Flyer]

Let’s shout together: “HOW CAN YOU KNOW IF ANY KIND OF SNOW IS ‘ADHERING’ TO THE SURFACES OF YOUR AIRPLANE, AND NO ICE IS BENEATH IT, IF YOU DON'T REMOVE IT?”
“No clean aircraft? No Fly!”

Most US operators require a close visual inspection and/or tactile check be performed if any contamination is observed on the wing surface (whether it's snow or ice).

FAA 8900.1 Volume 3, Chapter 27, Section 2 (http://fsims.faa.gov/PICDetail.aspx?docId=A370BBA38C0648F18525734F007665BE) pertains to the process by which ground de-icing programs are approved for air carriers under parts 121, 125, and 135.

For scheduled air carriers, by regulatory requirement of FAR 121.629 (http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c=ecfr&sid=051d4f3187cb84ad1d50d6739a783c23&rgn=div8&view=text&node=14:3.0.1.1.7.21.3.22&idno=14), a manner by which the operator can determine whether or not contamination is "adhering" to the wing must be described in detail. All flight crew members and de-icing technicians and vendors must be trained on the recognition and removal of ice and other contamination on the critical aircraft surfaces. If an air carrier lacks these procedures they cannot operate in ground icing conditions.

The common practice is a close visual inspection of areas suspected of having contamination and often a tactile inspection to determine whether or not de-icing is required and after the de-icing process to determine that the contamination has been adequately removed. In short, in the US all snow must be removed from the wing either by mechanical means (guys with brooms), by putting the aircraft in s heated hangar and letting the snow melt off, or if the temperature is such that ice will not accrue - using heated water to remove the snow. Of course using the glycol/water mixture is also an option though airlines try to avoid it due to the cost.

[HotDog]

I guess there is not much scope to experience deicing methods in Hawaii but your hot water choice conjours images of the FO climbing out of the overwing exit with a jug of boiling water from the galley.:E

[DOVES]

Island-Flyer Welcome on board. I envy you for the place where you are living. I remember that all American pilots who flew with me for an airline in the Gulf, in the late 90's, often said that they would be retiring in Honolulu. It never snows there does it!? Thank you for copying / pasting the FAA rules (I’m supposed to know them because I have an ATP), about aircraft de-icing. The common practice is a close visual inspection of areas suspected of having contamination and often a tactile inspection to determine whether or not de-icing is required and after the de-icing process to determine that the contamination has been adequately removed. How do you see if there is a deposition of snow, ice, or bird feces on the upper surface of the horizontal stabilizer of a DHC-8? Whether a pilot has 20,000 hours or 2000 hours they can both make critical mistakes. At my company we call "experience" "tribal knowledge" and actively discourage it. Does it apply also to people like me who has 22,000 hours? Of course I always left other fly desks, because I've always preferred, and still prefer, the "stick and rudder". Is it too little 35 years and over of flying in Europe, of wich at least ... let’s say ... many thousand hours in conditions of snow, ice, etc.. etc.. etc..? Have you ever seen this video?: Tailplane Icing (http://video.google.com/videoplay?docid=2238323060735779946) Look and learn from other’s experience. Let’s shout together: “HOW CAN YOU KNOW IF ANY KIND OF SNOW IS ‘ADHERING’ TO THE SURFACES OF YOUR AIRPLANE, AND NO ICE IS BENEATH IT, IF YOU DON'T REMOVE IT?” “NO CLEAN AIRCRAFT? NO FLY!!!" Fly Safe DOVE

[AirRabbit]

But, what about:
Let’s shout together: “HOW CAN YOU KNOW IF ANY KIND OF SNOW IS ‘ADHERING’ TO THE SURFACES OF YOUR AIRPLANE, AND NO ICE IS BENEATH IT, IF YOU DON'T REMOVE IT?”
“No clean aircraft? No Fly!”
Which is at the root of this thread.
Of course it would be somewhat foolish to completely dismiss your recommendation – but, at the same time, if the wing must be absolutely clear of any accumulation of snow (to see that there is absolutely no ice adhering) wouldn’t that effectively eliminate any takeoff during a snow shower? Is that acceptable to the myriad of operations that take place daily in locations where snow appears during winter operations?

[warmkiter]

what do you actually mean:

" Is that acceptable to the myriad of operations that take place daily in locations where snow appears during winter operations?"

are you trying to suggest, that because it snows so often and so many airplanes operate in winter conditions, a clean wing concept is not acceptable? It might even cost money and maybe cause delays?

By all respect to your ex mil, ex airline, now evaluation what ever that means -background and even claiming to have an ATPL, you should know better.

There is no option for clean wing! How farking difficult is that to understand? Why do all evaluators, midwifes, clerks, PPLs, wanna be pros etc try to prove it different?

A lot of lives have been lost because persons thought a clean wing concept is not necessary. A lot of lifes will be lost in future, because still some idiots dont learn from mistakes and try to know it better.

make it clean and keep it clean

[Rabski]

"make it clean and keep it clean"

Nothing more needs to be said. delay? Extra cost? So damned what.

The flight before got airborne, as did the one after eh? Simple maths therefore suggests a one in three chance of not making it.

Not particularly good odds are they?

Really, there is enough experience and worse, enough buried dead, to make the point perfectly clear. The regulations stipulate it. The SOPs stipulate it. Common sense stipulates it.

Even the 'Bus computers can't change the basic physics of flight.

Contamination = no go.

[AirRabbit]

Mr. warmkiter and Mr. rabski:

Thanks for the simplistic response (and that is NOT an insult) – with which, by the way, I completely agree! As I said earlier, from your lips to the hearts and minds of aviators everywhere! It certainly isn’t me that you have to convince ... it’s the airline owners/operators and the various regulators who have to deal with those owners/operators.

[DOVES]

AirRabbit Nevertheless you will agree with me that the following illegalities were committed: - They did not insert Engine Anti-ice after start, and did not perform the periodic engine run up. At 1538:16 while accomplishing after-start checklist items, the captain responed “off” to the first officer’s callout of checklist item ‘anti-ice.”… …During preparation of the CVR transcript, members of the CVR group could not agree on the response to the checklist callout “anti-ice”. The majority believed that the response was “off,” but that word was put in parentheses in the transcript to indicate questionable text. The Federal Bureau of Investigation (FBI) Audio Laboratory was requested to perform an independent examination of that portion of the tape. The FBI concluded that the response to the checklist callout “anti-ice” was “off.” … … Each of the two engines was equipped with a thermal anti-ice system, composed of three anti-ice valves which are designed to open when the respective engine anti-ice switch is placed ON. The inlet guide vanes and nose cones use 8th stage compressor bleed air and the cowl anti-ice system uses 13th stage air. The left engine’s 8th and 13th stage engine bleed air ducting on the right side of the engine was crushed between the 1:30- and 4:00- o’clock positions. The engine’s nose cowl thermal anti-ice valve was closed. The main bleed air valve was closed, The fuel heat valve was closed. The left inlet guide vane anti-ice valve was closed. The right inlet guide vane anti-ice valve was open and free to rotate. The air turbine starter was not visibly damaged. The right engine’s right inlet guide vane anti-ice valve was closed. The left inlet guide vane anti-ice valve was not recovered. The nose cowl anti-ice valve was closed. The engine bleed valve was closed. The modulation/shutoff valve was closed.The fuel heat valve was closed. The air turbine starter exhibited no visible damage. The pressurization and bleed control was not visibly damaged. The control was disassembled and no mechanical discrepancies were noted, except that it was clogged with water and dirt. The 8th stage and two 13th stage antisurge bleed valves functioned normally. They tried invain to push back (the tug connected) through the use of reverse (thus raising clouds of snow and slush). Adcording to the tug operator, the aircraft’s engines were started and both reversers were deployed. He then advised the flightcrew to use only “idle power.” Witnesses estimated that both engines were operated in reverse thrust for a period of 30 to 90 seconds. During this time, several Air Florida and American Airlines personnel observed snow and/or slush being blown toward the front of the aircraft. When the use of reverse thrust proved unsuccessful in moving the aircraft / back, the engines were shut down with the reversers deployed. They knew they had snow on the wings, so that they approached the preceding DC9, in the vain hope that their jet engines would swept it away. …At 1540:42, the first officer continued to say,. “it’s .been a while since we’ve been deiced.” At 1546:21, the captain said: “Tell you what, my windshield will be deiced, don’t know about my wings.” The first officer then commented, “well--all we need is the inside of the wings anyway, the wingtips are gonna speed up on eighty anyway, they’ll shuck all that other stuff.” … At 1548:59, the first officer asked, “See this difference in that left engine and right one. The captain replied, “Yeah.” The first officer then commented, “I don’t know why that’s different - less it’s hot air going into that right one, that must be it -- from his exhaust - it was doing that at the chocks 5/ awhile ago. . . .ah.” At 1551:54, the captain said, “Don’t do that - Apple, I need to get the other wing done.” They started the take off run 50 minutes after the de-icing.…The deicing/anti-icing of Flight 90 was completed at 1510. … …At 1559:46, the sound of engine spool up was recorded, …. They accepted a very little separation with the landing traffic despite the poor visibility and the snow storm. (If they had to abort the takeoff? If the others were to go around?) They underestimated the irregularity of the engines parameters for takeoff …Between 1600:05 and 1600:10, the first officer stated, “. . . that’s not right. . .,” to which the captain responded, “Yes it is, there’s eighty.” The first officer reiterated, “Naw, I don’t think that’s right.” About 9 seconds later the first officer, added, “. . . maybe it is,” but then 2 seconds later, after the captain called, “hundred and twenty,” the first officer said, “I don’t know.” They had found that the acceleration was so poor that they had reached 120 knots after 45 seconds. From 1559:46 to 1600:21 They began to rotate as per “the soft field” (I began to hear such an expression only since I'm instructing in general aviation) and then starting the rotation well before Vr. ...and 1558:37, the first officer asked, “Slush (sic) runway, do you want me to do anything special for this or just go for it.” (The first officer was the pilot flying the aircraft.) The captain responded “unless you got anything special you’d like to do.” The first officer replied: “Unless just take off the nosewheel early like a soft field takeoff or something; I’ll take the nosewheel off and then we’ll let it fly off.”
Let’s shout together: “HOW CAN YOU KNOW IF ANY KIND OF SNOW IS ‘ADHERING’ TO THE SURFACES OF YOUR AIRPLANE, AND NO ICE IS BENEATH IT, IF YOU DON'T REMOVE IT?” “No clean aircraft? No Fly!” Fly Safe DOVE

[AirRabbit]

The flight before got airborne, as did the one after eh? Simple maths therefore suggests a one in three chance of not making it.

Not particularly good odds are they?

Really, there is enough experience and worse, enough buried dead, to make the point perfectly clear. The regulations stipulate it. The SOPs stipulate it. Common sense stipulates it.
I’m not sure how many more times I’ll have to say this to get the point across ... the accident airplane DID NOT crash because of the accumulation of snow fall experienced between the gate and the takeoff. The aircraft crashed because it was deiced with hot water – that process specifically deposited water on the entire aircraft – fuselage, wings, engine inlets, everything. Where upon that water promptly froze – deforming the wings, and producing the effect that the B-737 had been known for doing – producing the same effect that almost crashed the B-737 departing from Oslo, Norway on that same day – producing an unexpected and uncontrollable pitch-up – to a point that was not recoverable – regardless of what control application was applied by the flight crew. This was not a “one-in-three” chance of snow fall exposure resulting in an accident - the reason that the airplane preceding the accident airplane and the airplane following the accident airplane did NOT crash is that they were merely exposed to the same snow fall experienced by the accident airplane – NEITHER of them were deiced with WATER – as WAS the accident airplane.

[warmkiter]

thats good news. one aviator less to be concerned about. :-)

I have to say that i havent met too many operators/airlines you have to convince, that the clean wing concept is the only way to do it. Its quite the opposite. In the SOPs its clearly written, that the aircraft must be operated with a clean wing only. No manufacturer or legislator would accept any deviation from this.

Its us, the pilots who deviate from the SOPs and finally cause the accidents. We as pilots have to take care that every one of us understands the importance of the clean wing concept.

Here comes the tricky part. As soon as some pilot starts to fool around and takes a chance not to de-ice or communicates to other pilots why it is not necessary to de-ice, the seed for the next accident is laid.

The foolish comments like:"dry snow will be blown away" or "the snow is not "adhering" to the surface", are perfect examples of how the cancer of misinformation is passed on. That particular flight may get away with it, but somebody will take an example of it and he might not be as lucky.

Thats why we, as the last line of defence, have to show zero tolerance to any deviation of the SOPs. If not us, then who?

This by the way. this applies pretty much to all other SOPs too. Its the collective behaviour of a group of pilots within a company, which makes the safety culture. Deviation may work well once for a pilot with superior skills or just plain stupid luck, but for a group of pilots it will be deteriorating the level of safety.

Flying is expensive, delays and de-icing cost money. Try an accident, that is even more expensive.

[rgbrock1]

AirRabbit wrote:

the reason that the airplane preceding the accident airplane and the airplane following the accident airplane did NOT crash is that they were merely exposed to the same snow fall experienced by the accident airplane – NEITHER of them were deiced with WATER – as WAS the accident airplane.

wouldn't the preceding and following aircraft have gone through the same de-icing station?

[Rabski]

"I’m not sure how many more times I’ll have to say this to get the point across ... the accident airplane DID NOT crash because of the accumulation of snow fall experienced between the gate and the takeoff. The aircraft crashed because it was deiced with hot water – that process specifically deposited water on the entire aircraft – fuselage, wings, engine inlets, everything. Where upon that water promptly froze – deforming the wings, and producing the effect that the B-737 had been known for doing – producing the same effect that almost crashed the B-737 departing from Oslo, Norway on that same day – producing an unexpected and uncontrollable pitch-up – to a point that was not recoverable – regardless of what control application was applied by the flight crew. This was not a “one-in-three” chance of snow fall exposure resulting in an accident - the reason that the airplane preceding the accident airplane and the airplane following the accident airplane did NOT crash is that they were merely exposed to the same snow fall experienced by the accident airplane – NEITHER of them were deiced with WATER – as WAS the accident airplane."


You can say it as many times as you like, but you will still be missing the basic point.

It doesn't matter whether you have ben de-iced with standard fluids, hot water or Bishop's Finger mixed with Baileys, as a flyer, it's YOUR responsibility to ensure surfaces are clean before aiming at the blue bit. How bloody complicated is this FFS?

Left seat? YOUR RESPONSIBILITY.

YOUR RESPONSIBILITY TO MAKE SURE IT'S ALL CLEAN.

So, it wasn't proerly de-iced and it froze again. IME, nothing new there.

FFS, it's really not that difficult is it?

OK, somebody didn't de-ice properly. The de-icing mixture wasn't correct. The Lear Jet in front of me didn't blow the snow off the way I expected, etc. etc.

Christ, despite my comments in another thread, I hope to hell I never get anyone with your attitudes in the RH seat when I'm flying.

I want to live to retirement thank you. If that means spending some of my employers' hard earned on excessive de-icing, then I couldn't care in the slightest.

Beats the hell of of the alternative...

[AirRabbit]

Mr. Doves:

I’m not going to go through the process of quoting your recent post ... so please forgive the fact that you may have to re-read your post to determine the specific points to which I’m addressing my comments ... but, I suspect you’ll probably be able to figure it out.... as I think you kindly provided “red” type for the relevant comments...

The B-737 engine “anti-ice” switches send a signal to the engine anti-ice valves (plural) and to the main engine control. Each anti-ice valve is electrically controlled and pressure actuated.
It shouldn’t take a rocket scientist to determine that an electrically controlled valve (taking both electrical power and pressure to open it) closes when both electrical power and engine pressure are removed - and there are very few (if any) who believe that the engines remained running providing both electrical power and engine pressure after the crash. Without power and pressure – what position would the valve resume? Right ... it would CLOSE. And, in case that isn’t clear enough, here’s a quote from the Accident Report...

ENGINE ANTI-ICE VALVES FAIL IN THE CLOSED POSITION (AVOID ICING AREAS)
However - it wasn't the use or the non-use of engine anti-ice that caused the crash. Yes, there was ice blocking the PT2 probes ... and that caused the EPR readings to be higher than actual. But there was still 75% power being produced by both engines. That was sufficient to get the airplane to at least 150 knots - but the airplane crashed anyway. So power setting - with or without engine anti-ice - was not the cause of the accident.
When the use of reverse thrust proved unsuccessful in moving the aircraft / back, the engines were shut down with the reversers deployed.
I’m not sure what point it was that you were making with this specific comment ... I am fully aware that the flight crew opened the engine reversers in an attempt to counter the forward thrust that idling engines would produce so that the smaller tug would have a better chance to push the airplane off of the gate and up the slight inclined that was present. That effort was not successful. The engines were shut down and a larger tug, equipped with tire chains was brought in to complete the push back.

They underestimated the irregularity of the engines parameters for takeoff.
I am also fully aware of what was said and who said it. However, you are presuming that what the F/O said had reference to an “engine anomaly.” I’m not sure what anomaly you may think he was referencing, but the fact is that for some 20 seconds both the Captain and the F/O were apparently attempting to determine what it was that was causing the F/O to say what he said. If there was an engine anomaly, it certainly wasn’t apparent to either crew member for at least that length of time. It is my opinion (and no, I can’t prove it – but it is my opinion) that the F/O was feeling something “out of sorts” and that was the position of his hand and arm when on the throttles when the engine instrument readings were apparently indicating what they should have been indicating. Only he would have had that “feeling” and the Captain would not have noticed. Muscle memory is a very important issue when accomplishing something in a routine manner. The engines were, in fact, operating just as they should have been operating – except that the PT2 probes were blocked with ice and were producing only about 75% of the takeoff power they should have been producing. With the kind of limited visibility that existed at the time, external references would have been of little or no value to assist in judging airplane acceleration.

They started the take off run 50 minutes after the de-icing.
I hope we’re not going to rehash your entire previous post ... I am fully aware of when they started their takeoff roll. And as I said the airplane immediately preceding and the airplane immediately following were both subjected to the same inclement weather that affected the accident airplane. Yet it was only the accident airplane that crashed. And, as I just pointed out to rabski, the crash was not a 1-in-3 gamble ... the crash was caused by the ice build up on the accident airplanes wings ... put there by the deicing crew when they sprayed water all over the airplane and the engines.

They began to rotate as per “the soft field” (I began to hear such an expression only since I'm instructing in general aviation) and then starting the rotation well before Vr.
As I indicated to you in my earlier response ... the F/O did NOT begin the rotation “well before Vr. The computed V-speeds (again, for your information) were V1 = 138 knots; Vr = 140 knots; and V2 = 144 knots. The CVR clearly shows the Captain calling out “Vee One.” It was 2 seconds later that the Captain said “Easy!” Again, I can’t prove it – except to note the rate of climb shown on the limited Flight Data Recording at that time – but it makes sense that this comment was a result of the airplane being rotated at an unusually high rate of rotation to an unusual and abnormally high attitude – NOT by the F/O deflecting the elevator controls, but rather because of the asymmetrical longitudinal lift that was being generated because of the ice-deformed wings – again created by the deicing crew.

If what you’re concerned about was the fact that the crew elected to depart with some accumulation of snow on the wings – I’ll agree that is just what they did. Although, being able to see the wings from the cockpit is not an easy thing to do in a B-737 – where only about the outboard 10 -12 feet are typically observable from the cockpit. If you want to criticize them for taking off with whatever snow accumulated during their taxi – you would be correct and I won’t argue ... but the same thing would have to be said for Apple 58 and Six Eight Gulf. Leaving the same question ... why would only one of those three aircraft not be able to fly? And clearly, it was the inadequate and insidious deicing process this one airplane experienced – and had nothing to do with the snow that accumulated.


You can say it as many times as you like, but you will still be missing the basic point.
It doesn't matter whether you have ben de-iced with standard fluids, hot water or Bishop's Finger mixed with Baileys, as a flyer, it's YOUR responsibility to ensure surfaces are clean before aiming at the blue bit. How bloody complicated is this FFS?
Mr. rabski
To the contrary ... I'm not missing any point. I know what happened and why. I fear it is you who fail to understand what happened. I am disappointed in that you absolutely refuse to understand the thought processes that were routine some 30 years ago – we used to think that asbestos was a good insulator – we used to think that cigarette smoking was a pleasant past-time – we used to think that 8 miles-per-gallon was reasonable mileage for a car – we used to think it appropriate for parents to send their kids to the park to play all by themselves – we used to think that taking off with a small amount of snow accumulation on a wing that had been recently deiced was OK (and there are some who STILL think that way – apparently including the various regulatory authorities). If you too wish to criticize that flight crew for taking off with some accumulation of snow on the wing ... be my guest. They did that. However, as I’ve been saying all along ... THAT was not the reason they crashed!

[Basil]

the thought processes that were routine some 30 years ago . . . . we used to think that taking off with a small amount of snow accumulation on a wing that had been recently deiced was OK
Well, in the seventies I'd left the RAF and was flying for BEA/BA and we didn't think it was OK to go with any contamination on the top of the wing.

[Rabski]

I still think it's appropriate to send children off to play by themselves I'm afraid, but then I often find myself apart from current thinking in some cirsumstances.

However, something like 30 years ago I was doing my PPL. With an instructor, God bless him, who told me in no uncertain terms more than once that it wasn't OK to go for it if there was so much as a squashed gnat on the wing, let alone some snow.

He was qute right then and he still is now.

Whichever way you look at it, the reason for the crash was contamination on the flying surfaces, and it's been the reason for a number of fatal incidents. It wasn't permitted or excusable then, and it isn't now.

Enough lives have been lost to make this a point that never needs to be debated surely.

[PukinDog]

AirRabbit
Of course it would be somewhat foolish to completely dismiss your recommendation – but, at the same time, if the wing must be absolutely clear of any accumulation of snow (to see that there is absolutely no ice adhering) wouldn’t that effectively eliminate any takeoff during a snow shower? Is that acceptable to the myriad of operations that take place daily in locations where snow appears during winter operations?


It's pretty simple. To begin the T/O roll, you must have a clean wing, critical surfaces, etc. that are free of frost, ice, or snow. "Clean" can include anti-ice fluid that hasn't failed/reached its saturation point. If its not wet and glossy but turned opaque, and especially if there's snow present on the fluid surface, the solution has lost the ability to melt frozen precip and absorb/suspend/depress the freezing point of the water. Unless other procedures have been approved in the Ops Specs, the general rule for U.S. air carriers (121.629) if HOT has been exceeded there must be pre-takeoff contamination check accomplished within 5 mins before T/O, and it must be done from outside the aircraft. If the pilot has miscalculated the precip type/intensity or other variables came into play (rapidly chancing temp/wind/jet blast) that cause visual indications the fluid has failed within the HOT, the pre-takeoff contamination check from outside the aircraft within 5 mins must still be done. When the fluid has become saturated, it's impossible for a pilot inside the aircraft to visually ascertain if there is re-freezing/adhering to the critical surfaces underneath the fluid. There are no "representative surfaces" for the contamination check, only the real ones. Since the manufacturers of fluids do not give a holdover times for heavy snow conditions, it did use to cease t/o operations because it threw Type 4 HOT tables out of whack, but now it's allowed if it's applied at 100% strength and a "definitive fluid failure determination" made within 5 minutes of takeoff.

In any case, no matter how you're trying to parse it, if it's not a dry, feathering snow readily sliding off a cold-soaked wing but is accumulating on it instead, then it must be adhering somewhere...you certainly can't make a definitive determination that it isn't. If it has accumulated on the surface of de/anti-ice fluid, the fluid has failed. In either case, this "accumulation" of snow it doesn't meet the criteria "free of". It's contaminated. Period.

some 30 years ago – we used to think that asbestos was a good insulator – we used to think that cigarette smoking was a pleasant past-time – we used to think that 8 miles-per-gallon was reasonable mileage for a car – we used to think it appropriate for parents to send their kids to the park to play all by themselves – we used to think that taking off with a small amount of snow accumulation on a wing that had been recently deiced was OK

30 years ago was 1982. There had already been 2 oil crises, everyone knew asbestos and smoking were bad for you, and it was already loud and clear that frost, ice, or snow on the wings during takeoff could kill you. At least in my neck of the woods where it was lousy with all 3. It was certainly widely disseminated aviation knowledge, but I realize that doesn't preclude pilots out there making up their own theories that become culture within fenced-off circles, those within convincing themselves it's routine thinking; "This type of wing handles it", "That'll slide off I've seen it before". There's always pilots that theorize about CBs too...the "Oh that's just rain" type who once flew through the red blob of a dying airmass baby in Florida who then supposes that's what he'll find inside a steady-state Level 6 over Kansas. The same mentality that screws around with snow on the wings and red on the radar stands a good chance of pushing their own metal into the smoking hole.

[Island-Flyer]

Island-Flyer Welcome on board. I envy you for the place where you are living. I remember that all American pilots who flew with me for an airline in the Gulf, in the late 90's, often said that they would be retiring in Honolulu. It never snows there does it!? Thank you for copying / pasting the FAA rules (I’m supposed to know them because I have an ATP), about aircraft de-icing. Thank you Doves, I wasn't really directly speaking to you though I did quote you - it was more a general statement. Thankfully we don't get much ground icing here in Hawaii, though prior to this I was based in Spokane. I realize those of us in the US understand the standard by which aircraft are de-iced but wanted to publish the general standard for those not familiar with why we operate with a "clean wing" concept.

We often discuss how much ice is too much for take off. We determined that if there isn't enough room for at least six drinks in the cooler then we must de-ice.

[Basil]

Island-Flyer, ROTFL (as the young people put it) :)

This is turning into a clay pigeon shoot for trolls. (Please tell me the 'OK to go' posts are from trolls.)

[Checkboard]

If you too wish to criticize that flight crew for taking off with some accumulation of snow on the wing ... be my guest. They did that. However, as I’ve been saying all along ... THAT was not the reason they crashed!
AirRabbit, changed your tune? :confused: Up until now you have been adamant that the snow on the wing (causing a pitch-up) WAS the reason they crashed! Your argument was that the "mis-set engine thrust" (due engine anti-ice being off) was the red-herring. :8

[J.O.]

Many years ago I met a member of the NTSB team that investigated Palm 90. I asked him if he believed that the accident would have been avoided if the crew had applied full thrust. His response was that if they'd have had full thrust, all it would have done was make an unflyable airplane unflyable a little bit sooner.

For what it's worth.

[40&80]

Possibly BEA were ice adverse in the 1970's and present trainers still are ...as a result of the massive bad publicity over their crash that killed most of the Man U football team...I think it was an Ambassador type aircraft and occurred on takeoff at Munich?

[Jetaim]

The misunderstandings here are at a cultural level.
Most of you assume Russian pilots being by some degree inferior to western pilot. Yeah right. If you don't speak English with a Brisbane, Mid west or London accent you don't know anything about aviation. Well.. let's not forget that English is today the official aviation language just because a war was won. And this also by nuking and killing 650000 Japanese man, women and children ( plus another 2.4 million on the medium long term) with a bomb built by German and Italian scientist. Let's be honest, not really something you can go proud of and almost on par with the Holocaust the irrefutable inhumanity of which, a little bit too often, our Jewish friends get to remind us one way or the other.
In this case many forgot that Aeroflot was, before the fall of the Wall the open the gate to ruthless capitalism and the globalization that are eating a bit of your T&C for breakfast every morning while filling the pocket of your "managers" , by far the biggest airline in the world with 3500 destinations just in Russia. Saying that Aeroflot has no clue on dealing with winter ops is a paradox. They are probably the most expert in this field.
The magic word is "adhering" . the definition of which is " to stick fast by or as if by suction or glue"
Dry uncompacted powdered snow is definitely not "adhering" to the surface of the wing. The crew most probably checked visually for the absence of ice underneath and decided that de-icing was to to do more arm than good seen the temperature and wx conditions. 100% legal.The snow blew away during the take off roll as the de-icing fluid would have done. Period.
If you still have any doubts on Russian competence just compare the number of failure and disaster the US had on their space programs when compared to USSR and consider the flawless regularity with which the Soyuz still today goes back and forth from Star City to the ISS and back at a fracytion of the cost of the Shuttle. Beside that I don't know how many of you know that the engine of the US Atlas 5 rocket main stage are the Russian-built RD-180. So please, nothing personal here, but Britons arrogance sometimes gets really annoying. Send the video to the Queen.. if you like. Dasvidaniya.

[warmkiter]

another clueless writer, your post wasnt even two kopejka worth ;-)

Its not about Russia, politics, capitalism, Atlas rockets, ISS or soviet era aviation...

this is about clean wing concept. What you obviously dont understand or want to understand.

it would be easy to beat the dead horse and talk about the accident rates in the soviet era and there after. In one word: Catastrophic

swallow down your pride, these guys in the video farked it up and there is absolutely nothing to excuse it!

Learn from mistakes and try to prevent accidents!

[rgbrock1]

As a member of the SLF brigade I don't think I quite understand what Soviet-era rocketry, the Holocaust, the ISS and English as the language of aviation, have to do with taking off with a contaminated wing. But, maybe it's just me.

[PPRuNeUser0171]

I'm also a member of the SLF brigade and have been reading this thread with some interest. What I am more curious about is what happens to all the snow that blew off the wing - couldn't that lead to it freezing on the runway surface causing problems for other aircraft landing and taking off?

[Jockster]

All they needed to do was 'brush' the snow off the wing and thats de-icing complete = clean wing. Anti-icing wasn't necessary unless it is or is about to precipitate. Granted the airflow blew the snow off just like the brushing would but of course no guarantees.

However, if the pilots checked that the snow was not adhering to the wing AND there was no ice underneath AND their Ops Manual permitted this practice AND the Captain was satisfied that the wing would be 'clean' at lift-off then there is not really any problem.

In warmer climates we take-off with water on the wing all the time on the understanding that it blows off during the take-off run. I would be more than happy to apply the same premiss to non-adhering snow BUT my Company Ops Manual doesn't give me that degree of latitude.

I think the pilots of the former Soviet Union, Balkan and Scandinavian states are more used to extreme winter conditions than their southern european counterparts.

[Jetaim]

Before bashing other cultures would be at least nice to have one....

[PukinDog]

"The Snow Will Probably Blow Off" Method is really just Russian Roulette applied to aviation, using a lot of people packed into an aluminum tube instead of just one poor sucker who ends up with the bullet.

Tsk, always having to try and do things bigger, but I know that's a culture thing

[AirRabbit]

:suspect: AirRabbit, changed your tune? Up until now you have been adamant that the snow on the wing (causing a pitch-up) WAS the reason they crashed! Your argument was that the "mis-set engine thrust" (due engine anti-ice being off) was the red-herring.
Changed my tune? No! Emphatically no! The engine thrust issue was, and remains, a “red-herring.” Why? Because, even though the thrust was, indeed, less than full takeoff thrust, it was sufficient to accelerate the airplane to V1, through V2 and up to something on the order of 150knots. Whatever thrust was available was sufficient to get to that point. Again ... airplanes fly on airspeed – regardless of the method used to get that airspeed – and the airspeed reached by those mis-set engines should have produced enough thrust to continue flight. I don’t think I need to review (again) the certification capability of a twin-engine airplane. HOWEVER, the ice contamination (the REAL reason for the crash) caused such a pitch-up that an “Atlas booster” would have been required to recover the airplane!

Now, regarding the ice formation on the wings ...

Yes ... there was snow falling. But the accumulation of that snow was NOT the cause of the ice formation that caused the crash! I’ve said that there were at least 3 airplanes in that takeoff line (and I don’t need to repeat the specifics again – do I?) and only one of them crashed ... all three airplanes experienced the SAME exposure to the falling snow. So far ... only rgbrock1 has understood the problem ... at least he asked the question: wouldn't the preceding and following aircraft have gone through the same de-icing station? The answer is NO. At that Washington airport every airplane was deiced at their own gate by either their own airline or a contractor hired to do that job ... and I suspect that it is still the process in use today at that airport. It was only the accident airplane that was deiced using the improperly “repaired” Trump deicing vehicle – the vehicle from which they dispensed little more than water as they were “deicing” the airplane. At the same time they were washing what snow and ice had accumulated on the airplane after having sat at the gate for the time it was there and the airport was closed, the deicing crew were (very likely unknowingly) covering both the airplane, its engine intakes, and the ramp around the airplane with good, common, water ... H2O. And then, for good measure, the crew applied a “misting” of “anti-icing” (consisting of the same good, common, water).

The other airplanes in that takeoff line (specifically, the two that I’ve repeatedly referenced) were deiced at their own departure gates, using their own individually supplied mechanisms at that gate, using what I would suspect as being the solution of water/glycol that was appropriate ... not only would that solution have cleaned the airplane (and engine) surfaces, the amount of glycol in that solution would have been sufficient to have rendered any subsequent snowfall to be irrelevant - or at least that was the common thought process at that time. Apparently, that was what happened, in that both of those airplanes took off successfully. However, with the deicing on the accident airplane having been conducted with water, and that water having been applied to a cold-soaked airplane, it would have easily (and probably quickly) frozen into a thin film of likely clear ice. As anyone on this forum would recognize – a very thin film of clear ice on a B-737 wing is not easily recognized – even when standing on the ground immediately in front of the wing looking directly at the leading edge ... let alone looking at that wing through the 40-plus feet from the cockpit. It was THAT contamination that caused the uncontrollable pitch-up ... it was THAT contamination that wouldn’t allow the forward control column movement to bring the nose back down to a reasonable attitude.

Regarding the ice formation on the engine intakes ...

The water that was deposited on the cold-soaked engine intakes in the same deicing and anti-icing process ... also froze ... and was likely the cause of blocking the PT2 probes. Some readers here believe that engine anti-ice was not used – others are not sure. The fact that the valves on the engines were found either closed or “open and free-wheeling” are, in my estimation, inconclusive, in that these valves were designed to fail to the closed position when the electrical power and engine pressure were taken away (crashes tend to do those kinds of things) it is likely that these valves – other than being damaged in the crash - would have been closed. BUT, the over-riding point is – if the engines had been producing 100% power from the initiation of the takeoff roll AND the crew attempted rotation at the designated rotation speed (as they did – again ... read the CVR transcript) the deformation of the wing would have still caused the uncontrollable pitch-up ... to the uncontrollable, and therefore unrecoverable, pitch attitude, and the accident would have occurred in essentially the same way. However, as observed earlier, in that case there might be some likelihood that the crash could have occurred prior reaching or after passing the bridge that was impacted during the crash ... and if it were missed, the 4 lives lost ON that bridge would not have been lost.

We can argue until the cows come home that the accident flight crew should not have taken off with whatever accumulation of snow on the wings had likely accumulated. But the accepted procedure at that time – again, just as followed by the other 2 airplanes (preceding and following) in that line – was to depend on the process that deiced and anti-iced their airplane. Had the accident airplane been deiced and anti-iced by a properly functioning system, it is more than just likely, it is almost understood, that airplane would not have crashed, but would have taken off normally. It was the flight crew’s dependence on that specific process, provided by that specific deicing vehicle, that cost them their lives and the lives of the others lost that day.

[Seloco]

I have, as SLF back in late 1980s at LGW, taken off in a 737 classic with similar amounts of snow accumulation. It blew off, we took off, and were soon up in the sunshine none the worse for wear.
Unfortunately the MD83 ahead of us was not so lucky. The snow from its wings went straight into the engines, which were unimpressed. The aircraft did get airborne, just, and then scared its pax witless burning off fuel before landing, at the second attempt, on Filton's long runway. It was a close call.

[lomapaseo]

These round robin arguments can not be won. The more words that are used the less they will be read by somebody looking to learn something.

many are sciolists

Ignore the poster and express an opinion once

[Cagedh]

@AirRabbit

I've read the NTSB report and I've read all your contributions to this topic.

I believe your side of the story. I think you're right! :ok:

[suninmyeyes]

40&80 you wrote

Possibly BEA were ice adverse in the 1970's and present trainers still are ...as a result of the massive bad publicity over their crash that killed most of the Man U football team...I think it was an Ambassador type aircraft and occurred on takeoff at Munich?


The Ambassador crash in 1958 was caused by slush on the runway and not ice on the wing.

[cwatters]

Probably not but that's not the point. A lot of things are done to ensure the safety of air travel in general even though there is no evidence a problem exists or existed on one particular flight.

Can we be sure the crew wern't sitting there up front worrying if they had made the right decision instead of concentrating on other checks?

[Pub User]

Snow was mostly blown away during takeoff roll, speaking aerodynamics-wise, did it really affect it adversely and had impact on safety?

It quite probably had a similar effect to having the speedbrakes up for the first part of the take-off run. The extra drag will have increased the amount of runway used before V1 and VR were achieved, thus completely invalidating the take-off performance calculations.

[PukinDog]

cwatters
Can we be sure the crew wern't sitting there up front worrying if they had made the right decision instead of concentrating on other checks?


Emperical evidence shows they were too stupid to worry.

[AirRabbit]

Well, it’s pretty clear, Mr. PukinDog, that you’ve made some interesting points …

1. “Clean" can include anti-ice fluid that hasn't failed/reached its saturation point.”

2. “If its not wet and glossy but turned opaque, and especially if there's snow present on the fluid surface, the solution has lost the ability to melt frozen precip and absorb/suspend/depress the freezing point of the water.”

3. “Unless other procedures have been approved in the Ops Specs, the general rule for U.S. air carriers (121.629) if HOT has been exceeded there must be pre-takeoff contamination check accomplished within 5 mins before T/O, and it must be done from outside the aircraft.”

4. “If the pilot has miscalculated the precip type/intensity or other variables came into play (rapidly chancing temp/wind/jet blast) that cause visual indications the fluid has failed within the HOT, the pre-takeoff contamination check from outside the aircraft within 5 mins must still be done.”

5. “Since the manufacturers of fluids do not give a holdover times for heavy snow conditions, it did use to cease t/o operations because it threw Type 4 HOT tables out of whack, but now it's allowed if it's applied at 100% strength and a "definitive fluid failure determination" made within 5 minutes of takeoff.”

It’s a shame that the crew of that accident airplane in January of 1982 were not aware of the kinds of things regarding airplane operations in icing conditions you listed. However, I would point out, for your careful consideration that most (if not ALL) of this information, these recommended practices, and these scientifically derived experimentation results you just provided were gained a result of the examinations, experimentations, arguments, discussions, decisions, and considerations conducted because there wasn’t sufficient information on these issues very readily apparent, or even available, prior to this accident? In fact, you used the term “hold-over time” (or HOT, the now-easily understood reference) but I would remind you (and all who are reading this) that, at the time of this accident, these terms, these facts, this information … was not very-well known by flight crews … not even by many of the folks that worked with and ultimately developed the solutions that were to be applied to ice-coated airplanes.

Look … I’m not here to “bust your chops” or insult the very professional aviator that you likely are. I’m only trying to show that the often misunderstood causes of this very specific accident were then, and still are, at times, just that … misunderstood. I’m not accusing anyone of any ulterior motive … I just want all of us to understand that there was a lot of pressure, from all sorts of positions, to get this accident resolved and move on! Just like anything that has negative consequences, those who knew more, or should have known more, are in the cross-hairs. It’s easy to spread the blame … I’m not looking to fix the blame on anyone … in fact, I’d much rather fix the problem than fix blame … and, to a very large extent, a lot of those problems have been very adequately addressed … at least I certainly hope and pray that they have been. We can’t ask the crew what was really running through their minds when they were commenting on other airplanes’ exhaust was apparently blowing onto their airplane. We can’t talk to the other Air Florida pilot (I apologize that I cannot remember his name) who was aboard, and was seated in the exit row window seat on the LHS of the airplane throughout this whole process. Why was he comfortable with what he was seeing outside his window … heck, did he even look outside his window? We can’t go back and ask the F/O what it was that caused him to question whatever it was that made him say what he said. We can’t ask that Captain why he did not elect to abort the takeoff. We don’t know why the deicing truck was “repaired” the way it was. Did anyone know that doing so would affect the results of its use? Why did the controller feel it was “OK” to clear an airplane for takeoff when there was another airplane on final approach well inside the FAF knowing that the visibility was as poor as it was? We now know these things and I would suspect that no one does them any longer. But the fact remains, they were done at that time. With what we know now, there are a lot of changes that have been made to a lot of “routine” process that are accomplished by flight crews on a daily basis – and that is a VERY good thing. We no longer “set power” by reference to the EPR gauges and then scan the instrument stack for symmetrical readings … we look specifically at the indications of the rotor speeds – noting the specific RPM percentage indicated. We look specifically at fuel flow – noting what the gauge actually indicates. Pilots do this routinely today – not just during inclement weather takeoffs. We are (at least generally) a lot more sensitive to where the engine exhaust is directed when we begin to move the airplane. We are a lot more careful about how closely we follow preceding airplanes on the taxiways. We are much more observant about the deicing process – we are more knowledgeable about the actual solution of glycol in the mixture being used to deice our airplanes. We know a lot more about “hold-over times,” and what compromises those times … and what must be done if they are compromised – if not by regulation – then by company – or personal – procedure. I think the professionals that manage the traffic at our airports are a bit more aware of how quickly landing traffic can get to the end of the runway – and how long pilots usually take to spool up, check what they want to check and set the “stuff” the way they want it, BEFORE they release the brakes for takeoff. All good things.

I just wanted to “set the record straight” - or at least “straighter” - than it is typically understood.

[DOVES]

For some reason my thread was deleted. So I will repeat it with some sweetening (and I will save my hard work this time ).
Mr AirRabbit: You’re so pathetic for the ardour with which you are defending the indefensible.
Anyone, with no exception, has the right to an advocacy, but in the trial, not from the trial.
We always say pompously: “to know exactly who or what is at fault for this crash before the plane's black boxes are examined and a full, professional investigation is completed. Let's wait for that to happen before we decide who deserves the blame.”
In this case we know exactly what happened thanks to the NTSB investigation.
All my Quotes (http://www.pprune.org/7151865-post357.html) have been extracted from the NTSB Aicraft Accident Report in spite you ascribe them to me (http://www.pprune.org/7152158-post362.html)
I urge all those who have not yet done so to read the report: Volo Air Florida 90 - Wikipedia (http://it.wikipedia.org/wiki/Volo_Air_Florida_90) http://www.airdisaster.com/reports/ntsb/AAR82-08.pdf
and:
http://www.airdisaster.com/reports/ntsb/AAR82-08.pdf (http://www.airdisaster.com/reports/ntsb/AAR82-08.pdf)

As I indicated to you in my earlier response ... the F/O did NOT begin the rotation “well before Vr. The computed V-speeds (again, for your information) were V1 = 138 knots; Vr = 140 knots; and V2 = 144 knots. The CVR clearly shows the Captain calling out “Vee One.” It was 2 seconds later that the Captain said “Easy!”

NTSB Report, page 5 line 25: “Eight seconds after the captain called “Vee one” and 2 seconds after he called “Vee two,” the sound of the stickshaker 91 was recorded.”
1) Did anybody call “Vr”? (Or rotate as US Pilots use to say?)
2) V2 was only 2 knots higher then Vr. And in spite of that they were already airborne (stickshaker activated).
Usually it takes 5 to10 seconds (6”: normal rate beeing 3° per second) to achieve a normal take off attitude of 20°
And as I said the airplane immediately preceding and the airplane immediately following
were both subjected to the same inclement weather that affected the accident airplane.
Yet it was only the accident airplane that crashed.
In science the interpretation of a phenomenon is recognized as a law only if its experience is replicable, otherwise it’s a chimera.
We, therefore, must learn from the mistakes of others in order not to repeat them, and must ignore their fortunes, unrepeatable.
I say in a choir with warmkiter: make it clean and keep it clean
and Rabski: Contamination = no go.
And many others.
You should too shout with me: “HOW CAN YOU KNOW IF ANY KIND OF SNOW IS ‘ADHERING’ TO THE SURFACES OF YOUR AIRPLANE, AND NO ICE IS BENEATH IT, IF YOU DON'T REMOVE IT?”
“No clean aircraft? No Fly!”

[AirRabbit]

Mr. Doves:

First, I am going to ignore the blatant insult, in the hope that it was only because you cannot understand my position … because of issues you cannot understand or choose to ignore. With all due respect … and, unfortunately, I fear, what is actually due with regard to that respect, is quickly expiring! You claim to know “exactly what happened,” and you cite the singular source for “knowing” all you say you know is that NTSB report … and I would presume, only, that report. The clear error you are making is believing only what you want to believe of that text and ignoring the blatant inconsistencies in that very same text.

Sir, as I believe I’ve said previously, I am fully aware of where you obtained the information you have “quoted” in your posts here. I am also aware, at least I believe, that the English language is not your first language (and if correct, you have my compliments for being as conversant as you are in English – I am conversant only in English – one of the not-so-admirable traits many of us Americans share…) but in that understanding there may be some room for your apparent misunderstanding of what is said in that report.

As merely one example of the confusion I am experiencing … are we who read your posts, to understand that if you do not hear the other pilot in your cockpit actually say out-loud, “Vee R” or “Rotate,” and failing to hear that verbal call-out you would not rotate? If you pass “Vee One” speed, later arriving at “Vee Two” speed … how is it that, in your opinion, you believe that the airplane did not achieve “Vee R” or “rotate” speed? Oh, by the way, one error in your reading of the transcript, sir … is your statements regarding “V2 speed” … the computed, briefed, (and believed set) “Vee Two” speed was actually 144 knots, and that is actually 4 knots higher than “Vee R” speed, which was also computed, briefed (and believed set) at 140 knots – although, admittedly, I’m at a loss to understand the significance you seem to attach to that relationship – whether it was the 4 knots the crew briefed (and most believe) used … or the 2 knots that you state. And NO, it’s not a requirement to call-out “Rotate” – and, while there are certainly some who do, not all flight crews make that call.

I also see that you note it wasn’t long after reaching “Vee Two” speed that the CVR transcript indicates the sound of the “stick shaker” begins. What that CVR transcript does not show is that on the actual recording there were very clear sounds of substantial buffeting – in fact, the buffeting noise was almost distracting to anyone listening to the CVR for the remainder of its recording. The airplane had not merely exceeded the AoA at which the stall warning was to be activated – it also achieved an AoA at least equal to, and very likely well beyond, the critical (stall) AoA – putting the airplane into an aerodynamic stall – from which all the obtrusive buffeting noise was generated.

Interestingly, you say that you are familiar with circumstances where it usually “…takes 5 to10 seconds (as you say "...the normal rate beeing 3° per second") to achieve a normal take off attitude of 20°” My suspicions are that you might be surprised to learn that I completely agree with your statements here … as, I too, am familiar with similar time requirements to rotate from a normal 3-point, ground contact position, to that normal takeoff attitude … although we used 18 degrees as “normal” … I’ll not quarrel with 20 degrees. At 3 degrees per second (a traditionally normal takeoff rotation rate) would take something on the order of 6 to 6 ½ seconds to achieve that normally achieved 18-20-degree attitude. With some of that waning respect I have left, I would question why it is that you choose to disbelieve, or you choose not to apply any relevance to the fact that the airplane rotated from the “3-point ground contact position” all the way to an attitude that exceeded the critical AoA (some witnesses said the pitch attitude was above 40 degrees) in in something on the order of a half to a third of the time it should have taken to rotate to what you describe as a “normal takeoff attitude.” For what it’s worth, you are not alone in that lack of understanding or that disbelief! But it happened. The facts are there. Clearly. It’s evident in the transcript, but those facts – as blatantly incongruous with other facts as they are – they are completely without comment, and are clearly indicative of some other factor that was either overlooked or was not given sufficient consideration, or was (and I do not like saying it) either deliberately or ignorantly suppressed in the deliberations that followed. The question remains … why would a B-737 rotate from a 3-point ground contact position to an attitude that puts the airplane at or beyond the critical AoA into an aerodynamic stall and do so well short of the time it would normally take to rotate only to 18 – 20 degrees? Is there anyone who really believes it was the F/O that “snatched” the airplane to that kind of attitude in that short period of time?? … when he had just stated that he was only going to rotate to get the nose gear into the air and “…just let (the airplane) fly off the ground”?? No one addressed this terribly obvious question. Additionally, after getting airborne, the transcript clearly shows the Captain repeatedly urging the F/O to move the control column “forward” … “come on forward” … “forward” … “just barely climb” … “we only want 500” … “forward.” Why doesn’t anyone question what that conversation was all about – and more importantly – why didn’t the F/O do what the Captain was urging him to do! Why didn’t someone take note of the fact that the Accident Report also includes statements from the airplane manufacturer that clearly shows that there was a “known tendency” for that airplane to “pitch-up” and/or “roll-off” when subjected to very minor amounts of freezing precipitation?? It seems more than just a little strange to me that such a potential was virtually ignored in the report and certainly was ignored in the conclusions reached ... particularly given the level of tragedy that occurred.

So, Mr. Doves … you continue to advocate a choir to sing the mantra that you so fervently desire … I’d just ask that if you’re going to put confidence into a report – that you do so with the ENTIRE report – and not selectively pick and choose portions of the report that seem to match and completely disregard any and all of those points that are horribly outside of any reasonable boundary for what you’ve chosen to believe.

[cwatters]

I'm curious.. It's well known contamination can increase the stalling speed but would the stick shaker also operate at a higher airspeed? How does the stall warning sensor know there is contamination or is it only looking at air speed and AOA?

[BobM2]

:ugh: Relax AirRabbit, you're never going to get through to those "holier than thou" who live in a more perfect world than ours. Just know that there are those of us who do get what you are saying--that deicing procedures & culture at that time & place were much less precise than now, there was no stated holdover time, & the cockpit crew knew that if they went back for another deice that they would encounter the same or worse delay for takeoff. We understand your very plausible theory that the airplane was thoroughly ICED by faulty deicing procedures which made it unflyable due to a sudden uncontrollable pitch-up at the point of rotation. We also understand that many of the contributing facts you mention were not included or were glossed over in the NTSB report.

Thank you for your very knowledgeable input.

[Clandestino]

Our esteemed PPRuNe colleague seems to share another trait with the legendary captain Dudley: persistence. While obvious t-person is obvious, his marveling on application of the second Newton's law on the frozen 737 racing down the runway with too low thrust (How did he achieve the V2? - See NTSB report, findings, #20) shows where many a debate here takes a wrong turn; folks with feeble grasp of elementary physics, building up advanced aerodynamic theories on flawed basic notions.

Connets has made an interesting point:

During my working years as an academic, I realised that we don't always ask what, precisely, we hope to acheive by the use of the penal sanction (and I include internal disciplinary proceedings). I would have thought that here it is not to exact vengeance, but to prevent the harm from happening. What is very well known to psychologists, penal law experts and sociologists but is cheerfully ignored by lawmakers and general public is that high chance of getting caught is far more powerful deterrent than severe punishment. It neatly explains people being pick-pocketed while watching the execution of pickpockets in Dickensian England or numerous executions for graft in country I shall not name due to political correctness.

Considering the laws of aerodynamics, that Mother Nature applies with absolute impartiality while showing no mercy, this observation might help to explain why-oh-why pilots keep on taking off with snowy or iced over wings. Possible punishment is capital, yet the chances that it will be meted out are slim. The snow might indeed slip off the wings and anything still clinging on as the aeroplane climbs out of ground effect is usually not enough to completely reduce the lift to the point below the weight. Afterwards, as ice melts, there's no way to tell whether the disaster was averted by a knot, five or ten and ignoramuses in cockpit go very long way to prove their experiment was both safe and legal. I find definition of take-off as being only the actual liftoff quite amusing, taken in combination with the big red warning at the bottom of the page.

However, I have seen far too many successful takeoffs with snow on the wings in the real life to kid myself with the notion that anyone advocating laissez-fair approach to ice is really an impostor. Seemingly, some Russians are not the only one susceptible to the malaise of ignorance. Or Spaniards. Or LoCo drivers. Or third world pilots. That fellow next to you might be infected too.

I'm curious.. It's well known contamination can increase the stalling speed but would the stick shaker also operate at a higher airspeed?No, unless aeroplane has modified stall warning threshold when operating anti ice devices, e.g. automatically with selection of flight controls horn heating (I forgot exactly which one) on ATR or manually selected on DHC-8. No such thing on A320 and I never heard about it on B737.

[BobM2]

I'm curious.. It's well known contamination can increase the stalling speed but would the stick shaker also operate at a higher airspeed? How does the stall warning sensor know there is contamination or is it only looking at air speed and AOA?

Actually that sort of makes AirRabbit's point, since the AOA vane only reads angle of airflow. If the airplane was rotated normally with the wing stalled at a lower than normal AOA due to ice affect, there would only be buffet sounds on the CVR. The stick shaker would not have activated.

[M.Mouse]

We will never know but AirRabbit's calm and persistent statements do make me inclined to believe that what he says may well be the reality of what caused the accident that fateful day.

The 'pitch up, roll off' characteristic of the B737 was well known. BA had a serious incident caused by this very phenomenon on take off out of Helsinki on a B737-200. It directly led to an increased speed procedure (possibly unique to BA), whose details I forget, in given conditions. The training captain who completed my training on the B737 was the co-pilot on the incident flight out of Helsinki and his description of the event when he related it to me in 1989 was as vivid and scary as it was when it occurred many years earlier.

[AirRabbit]

Our esteemed PPRuNe colleague seems to share another trait with the legendary captain Dudley: persistence. While obvious t-person is obvious, his marveling on application of the second Newton's law on the frozen 737 racing down the runway with too low thrust (How did he achieve the V2? - See NTSB report, findings, #20) shows where many a debate here takes a wrong turn; folks with feeble grasp of elementary physics, building up advanced aerodynamic theories on flawed basic notions.
Considering the laws of aerodynamics, that Mother Nature applies with absolute impartiality while showing no mercy….
Perhaps if our colleague here weren’t quite so “lost in Babylon” as he claims he is, he might be able to make himself just “a tad” more understandable. For example: am I the only one here who read “…while obvious t-person is obvious…” numerous times, each time attempting to understand just what the heck was being said? Immediately following that statement, we read “..his marveling on application of the second Newton’s law on the frozen 737 racing down the runway with too low thrust (how did he achieve V2? – See NTSB report, findings, #20)…” Again … am I the only one who read this while scratching his head, wondering … “what in the heck does THAT mean?” In the sheer hope that his reference to NTSB report finding #20 would provide some clue as to what he meant, I re-read that finding. It says, “The aircraft accelerated at a lower-than-normal rate during takeoff, requiring 45 seconds and nearly 5,400 feet of runway, 15 seconds and nearly 2,000 feet more than normal, to reach liftoff speed.” So, was the “real” point being made that the flight crew used less than full engine thrust on the takeoff? Geeze, I thought we all knew that. So … maybe we were being reminded that it was the use of that lower thrust level that caused the airplane to take 45 seconds and nearly 5400 feet of runway to reach liftoff speed? Geeze … again, I think we all knew that as well. So, perhaps he was making the point that many debates and some airplane takeoffs take a wrong turn? Ummm … I just don't know! Was he trying to let us know that he has a “feeble grasp of elementary physics” … and this sometimes causes him to “…build up advanced aerodynamic theories on flawed basic notions?” I’m not sure … maybe. Unfortunately, he jumps from this train of thought to one involving psychologists, penal law experts, Mother Nature., and cockpit ignoramuses – leaving us to determine into which category he would place himself … I guess.

Oh wait, wait … I think I’ve got it … perhaps Clandestino wants all of us to understand that when you have a group of “psychologists” who engage in a debate on penal law while attempting to rush a “frozen 737” down a runway, if they use “too low thrust” they just may “take a wrong turn” and have to appeal to Mother Nature, who will, as he correctly points out, meet out her decisions, “…with absolute impartiality while showing no mercy.” Or .... well ... maybe not.

[J.O.]

It's not just you.

[DOVES]

Mr AirRabbit
I am sorry that you have interpreted as a blatant insult the adjective “pathetic”.
The semiotic origin of the word is:
Pathos; plural: patha or pathea; Greek: πάθος, for "suffering" or "experience;" adjectival form: 'pathetic' from παθητικός) represents an appeal to the audience's emotions. Pathos is a communication technique used most often in rhetoric (where it is considered one of the three modes of persuasion, alongside ethos and logos).
Is there anything hurting someone’s feelings? On the contrary!
It has already been noticed that I'm not very familiar with the English language, that’s why I didn’t struggle to choose the most appropriate word to express the feelings given to me by your stubbornness in defending the actions of the pilots of Air Florida Flight 90, of January 13, 1982.
I do not know what’s the reason why you do so.
I can tell you that my ethical and logical motivation is that I am sick and tired of hearing and reading about plane crashes (which, thanks to God I am avoiding since more than 45 years) due to "Pilot error". And if I cannot save the world, all I need to know is that I gave someone a bit of my experience thus making him spare his aircraft and a number of lives.
I cannot be in an ailiner’s cockpit anymore to deice when needed, but I swear that I will claim, as a SLF, the airplane to be de-icede/anti-iced if I find myself in a situation like:
http://www.pprune.org/7127125-post1.html
And like Plutarch used to write at the end of a treaty.
On this subject it’s enough.

[Clandestino]

We will never knowWe can be never absolutely sure but if I may suggest somewhat radical approach towards the best possible understanding: reading the official report. As one PPRuNer mentioned:

Please understand that my motive in saying what I’m saying (and what I’ve said previously), is in no way intending to impugn the fine reputation or the integrity of the NTSB or of the dedicated and professional employees at the Safety Board.

There you have it! It not just their integrity, dedication and professionalism that counts, it is their expertize laid open in their reports for all world to see and discuss.

calm and persistent statements do make me inclined to believe that what he says may well be the reality of what caused the accident that fateful day.You should read the report. It's icy cold and consistent. I tend to rank consistency above persistence but it could be just me. It won't hurt to repeat the quote:



The National Transportation Safety Board determines that the probable cause
of this accident was the flightcrew’s failure to use engine anti-ice during ground operation
and takeoff, their decision to take off with snow/ice on the airfoil surfaces of the
aircraft, and the captain’s failure to reject the takeoff during the early stage when his
attention was called to anomalous engine instrument readings. Contributing to the
accident were the prolonged ground delay between deicing and the receipt of ATC takeoff
clearance during which the airplane was exposed to continual precipitation, the known
inherent pitchup characteristics of the B-737 aircraft when the leading edge is
contaminated with even small amounts of snow or ice, and the limited experience of the
- flightcrew in jet transport winter operations.

Pitch up characteristic of frosted ower 732 was contributing, not casual factor. If (hypothetically) anyone puts forward the theory of it being the main culprit while dismissing the real casual factors as "red herring" it would be conductive to entertainment, not to learning and understanding.


I'm curious.. It's well known contamination can increase the stalling speed but would the stick shaker also operate at a higher airspeed? How does the stall warning sensor know there is contamination or is it only looking at air speed and AOA?

It looks only at AoA and I have to stand corrected here; what I wrote is valid for AoA, not airspeed as:



Most air carrier aircraft are equipped with a stickshaker or some other type of
alarm to alert the pilot that his aircraft is approaching the stall angle of attack. In the
B-737, the stickshaker is activated when a fuselage-mounted vane aligns itself with the
airflow and reaches a preset angle of attack which is less than the stall angle of attack.
The normal alarm margin is equivalent to about 10 percent of the stall airspeed. Since
the stall warning activation is independent of the actual airflow conditions on the wing,
the angle of attack at which it will activate is not affected by snow or ice contamination
on the wing. However, if the wing’s lift-producing efficiency is reduced by such
contamination, the aircraft will be maintaining a higher than normal airspeed when flown
at the angle of attack at which the stickshaker will activate in order to compensate for
the degraded efficiency of the wing.

Thus, the stickshaker will activate at a higher-than-normal airspeed.

Furthermore, the angle of attack margin, and thus the airspeed margin, between
stall warning, stall buffet, and stall will be reduced significantly
or negated entirely.

[M.Mouse]

You should read the report.

Errrrr....actually I have, in full. Much like I read the BEA report into the Concorde crash.

They were the official reports so we must unquestioningly accept them, I agree.

[Clandestino]

You are agreeing with whom? Who said/wrote that official reports have to be accepted unquestioningly?

If there is a conclusion in the report, there must be a method described which led to it. This method has to be scrutable and found to be valid. Otherwise, it's not a report but rather a pamphlet.

Science is not a cult! It is not scientific if scientist says so. It is scientific if it is open to independent validation and confirmation (or disproving, if you're into Popper)

[AirRabbit]

In an earlier post, I said that ”…my motive in saying what I’m saying (and what I’ve said previously), is in no way intending to impugn the fine reputation or the integrity of the NTSB or of the dedicated and professional employees at the Safety Board.”
…and you respond with ”There you have it! It not just their integrity, dedication and professionalism that counts, it is their expertize laid open in their reports for all world to see and discuss.”

..and that is all I am doing. Taking their integrity, dedication, and professionalism … and discussing the conclusions they reached… which are the following.

The National Transportation Safety Board determines that:

The probable cause of this accident was
1) the flightcrew’s failure to use engine anti-ice during ground operation and takeoff,
2) their decision to take off with snow/ice on the airfoil surfaces of the aircraft, and
3) the captain’s failure to reject the takeoff during the early stage when his attention was called to anomalous engine instrument readings.

Contributing to the accident were
1) the prolonged ground delay between deicing and the receipt of ATC takeoff clearance during which the airplane was exposed to continual precipitation,
2) the known inherent pitchup characteristics of the B-737 aircraft when the leading edge is contaminated with even small amounts of snow or ice, and
3) the limited experience of the - flightcrew in jet transport winter operations.

Probable Causes … one at a time:
1. “…the flightcrew’s failure to use engine anti-ice during ground operation and takeoff…”
Just the other day, one of the PPRuNe Forum participants, J.O. posted the following:
Many years ago I met a member of the NTSB team that investigated Palm 90. I asked him if he believed that the accident would have been avoided if the crew had applied full thrust. His response was that if they'd have had full thrust, all it would have done was make an unflyable airplane unflyable a little bit sooner.
Clearly, this person must also have the same level of integrity, dedication, and professionalism as other members of the NTSB investigation team … right? Well … where was this person’s comments in the report? Selective editing? Comments are inserted on the basis of what … votes?

2. “…their decision to take off with snow/ice on the airfoil surfaces of the aircraft…”
While I know some will cringe once again – but facts are facts … there were other airplanes in that same takeoff line – exposed to exactly the same snow fall as the accident airplane was exposed … why the difference? You all know what I’m going to say … the difference was that no other airplane that day was deiced / anti-iced by the same deicing vehicle that deiced that accident airplane. Where was that comment in the report?

3. “…the captain’s failure to reject the takeoff during the early stage when his attention was called to anomalous engine instrument readings.”
This is another path we’ve been down several times. I’ve always wondered why it was that the NTSB was under the impression that the Captain’s attention was called to “anomalous engine instrument readings.” The F/O is the one who was asking questions. Did he say anything about the engines? No. He was rather vocal about something … no doubt. But he also seemed to be vacillating between questioning something and believing everything was OK. This issue was going on for quite a while – something like 20 seconds or so. Yet, nothing conclusive was ever said - and the engines were not mentioned. The interesting note here is that when the F/O made what I would call his first “declaration” and no longer questioning, when he said “Ah, that’s not right.” That’s not a question. But it was that F/O who 2 seconds later, apparently satisfied himself … he said “(Well”). Two seconds later the Captain said “Yes it is. There’s eighty.” A quick question for you aviators out there. Where was the accident airplane when the Captain said “Yes it is. There’s eighty”? How far down the runway do you get when your airplane gets to "eighty knots?" I ask because a scant 2 seconds later, the B-727 landing behind them called “Fourteen fifty-one cleared to land - over the lights.” Where was this B-727? Where was the accident airplane? If you were the Captain … would you have said “I’ve got the airplane” … taken over the controls … and the F/O would have to release control of the airplane (primarily getting his feet off of the rudder pedals). The Captain would then have gone through the abort procedures … bringing the throttles to idle smartly … and then into reverse, while applying as much toe brakes as he could muster … keeping the control column firmly forward (not too much) so that the nose gear would be firmly on the ground through all that ice and snow on the runway … maintain rudder pedal steering down the runway … while the F/O would have grabbed the microphone, raised it to his mouth and said something like “Palm 90 … aborting on the runway!” Where would that B-727 have been at THAT time? Again, I ask, if you were the Captain, knowing what that Captain knew, would you have aborted? I know a lot of folks who answered “yes” and a lot who answered “no.”

Contributing Causes … one at a time:
1. “…the prolonged ground delay between deicing and the receipt of ATC takeoff clearance during which the airplane was exposed to continual precipitation…”
Guess what gang … same response as provided in #2, above … there were other airplanes in that same takeoff line – exposed to exactly the same snow fall as the accident airplane was exposed … why the difference? Same answer … again … You all know what I’m going to say … the difference was that no other airplane that day was deiced / anti-iced by the same deicing vehicle that deiced that accident airplane. Where was that comment in the report?

2. “…the known inherent pitchup characteristics of the B-737 aircraft when the leading edge is contaminated with even small amounts of snow or ice…”
Whoa there folks! What is this? A characteristic of the airplane to pitch up – without any input from the crew? When would this happen? Oh … when there were “even small amounts of snow or ice” on the leading edge of the wing? Well … THIS could be really significant … right? Well, no actually … the NTSB decided that this was merely a contributing factor … not a “cause” of the accident. Really? I mean … really!?
Again, just the other day, another one of the PPRuNe Forum participants, this time it was M.Mouse posted the following:
The 'pitch up, roll off' characteristic of the B737 was well known. BA had a serious incident caused by this very phenomenon on take off out of Helsinki on a B737-200. It directly led to an increased speed procedure (possibly unique to BA), whose details I forget, in given conditions. The training captain who completed my training on the B737 was the co-pilot on the incident flight out of Helsinki and his description of the event when he related it to me in 1989 was as vivid and scary as it was when it occurred many years earlier.
Hmm … another “serious” incident … the NTSB had no interest in this or any other information about similar circumstances … even though they acknowledge – right there in the report – that this airplane type is KNOWN to do this? And it’s not significant enough to look any further? Really! Really?

3. “…the limited experience of the flightcrew in jet transport winter operations…”
This is easily one of the most questionable comments in the entire report. First, let’s look at what NTSB says about their experience. The report says the following:
The Safety Board reviewed the winter operations conducted by the captain and first officer and found that the captain, after upgrading to captain in B-737 aircraft, had flown eight takeoffs or landings in which precipitation and freezing or near-freezing conditions occurred, and that the first officer had flown two takeoffs or landings in such conditions during his employment with Air Florida, Inc.
Hmm… sounds pretty skinny … right? Let me ask a question of each pilot out there. Do you remember your first takeoff in ice or snow conditions? How experienced were you in making that kind of takeoff? How much experience should be required of pilots in making takeoffs in ice and snow before we should let them make takeoffs in ice and snow? Did the NTSB examine what the Captain and F/O did for a living before coming to work at Air Florida? Would that … could that have been an important issue? Don’t know about you … but I do. Unfortunately, I don’t know what the Captain had done in his years of flying prior to working at Air Florida … and I wonder if he had made any takeoffs or landings in ice and snow when he was a First Officer for Air Florida. Would that have made an interesting fact? Hmm… What was the F/O doing prior to coming to work at Air Florida? Well, he was an all-weather fighter/interceptor pilot, flying F-15’s, out of Minot, North Dakota. Hmm … probably not much ice or snow in Minot, North Dakota … right? (Shessh)

So ... we've had the "official" NTSB Accident Report for almost 30 years now. Will anything I say cause anything in that report to be changed ... no, certainly no. Does that mean that everything they said in that report is accurate and complete ... same answer ... no, certainly no. Why bring it up? Simple answer (not chacteristic of me but...) because I think the truth deserves its time in the light.

[de facto]

Hmm… sounds pretty skinny … right? Let me ask a question of each pilot out there. Do you remember your first takeoff in ice or snow conditions? How experienced were you in making that kind of takeoff? How much experience should be required of pilots in making takeoffs in ice and snow before we should let them make takeoffs in ice and snow?

I dont remember my first captain take off in snow conditions but I remember my first solo flight.
Every qualified airline captain should be able to read and do procedures laid down in their company FCOM during winter operations.
No need to be Einstein,just be able to read and follow the steps.
Now some captains who have a poor self discipline will tend to disregard standard AND supplementary procedures and this with a lack of winter ops has the potential to end up very badly indeed.
The skills needed to take off on a contaminated runway is purely based on experience/skills and therefore a new pilot in winter ops may have some problems in controlling the aircaft properly and/or during a reject if the case but should not be a danger in itself.

Company SOPs though normally have wind limitations for different level of contamination.

To make a long story short,even a baboon could follow the steps for a successful winter ops take off.
SELF DISCIPLINE is the lacking factor in most cases.

[Northbeach]

I’m surprised the moderator(s) have not moved this extensive and ongoing discussion of Air Florida-Palm 90 in Washington DC somewhere else as it has just about completely eclipsed the original post and direction of the thread discussing a recent takeoff with contaminated surfaces.

AirRabbit who obviously has an extensive knowledge base of the facts surrounding Palm 90 in DC, perhaps even worked for the operator or knew those directly involved, presents his position in great detail and with tremendous patience. Perhaps this discussion of the accident deserves its own thread.

With no disrespect to the dead, I am not interested in opening up a new investigation of that accident on this thread.

Let’s see if I understand AirRabbit’s point. It was not snow on the wing that doomed Palm 90, the aircraft had been deiced imperfectly and the wing was covered with ice as it rolled down the departure runway. The 737 pitches up with even a small amount of ice or contamination on the wing, a point that needs to be better understood. What doomed Air Florida was the 737’s pitch up tendency with a contaminated wing of the 737 design combined with ice that was present due to the method and equipment used to “deice” that jet on that day. The accident was not primarily caused by snow accumulation combined with the poor flight crew performance.

So, trying to summarize the multiple posts regarding Air Florida and applying them to the video on the original post I come up with the following. Contamination of any sort on the wing of a commercial T Category jet transport has the potential of rendering the wing incapable of safe flight. Therefore it should be removed prior to flight.

That puts us back to the “clean wing” concept right? Therefore the takeoff video clip that opened up this thread was a dangerous act and an expample of poor airmanship and decision making.

[PukinDog]

AirRabbit
It’s a shame that the crew of that accident airplane in January of 1982 were not aware of the kinds of things regarding airplane operations in icing conditions you listed. However, I would point out, for your careful consideration that most (if not ALL) of this information, these recommended practices, and these scientifically derived experimentation results you just provided were gained a result of the examinations, experimentations, arguments, discussions, decisions, and considerations conducted because there wasn’t sufficient information on these issues very readily apparent, or even available, prior to this accident?


I didn't say the crew in 1982 knew anything about anti-icing fluid. You've cherry picked points I made as an answer to these present tense questions of yours...


Air Rabbit quote;.. but, at the same time, if the wing must be absolutely clear of any accumulation of snow (to see that there is absolutely no ice adhering) wouldn’t that effectively eliminate any takeoff during a snow shower? Is that acceptable to the myriad of operations that take place daily in locations where snow appears during winter operations?.

.. your implication being anti-ice fluid hasn't been invented yet, and therefore, "how can anyone fly in snow?". I was pointing out it has been, and there seemed to be some confusion in various posts with regards to the presence of snow on top of fluid.

It's true 1982 crews didn't have those A/I fluids we enjoy now, relying only de-ice fluid with some assumed (but vague) anti-ice properties when applied as an aftercoat/overspray. That being said, I'll re-quote the main point I did make pertaining to what was known back in 1982..

..and it was already loud and clear that frost, ice, or snow on the wings during takeoff could kill you. At least in my neck of the woods where it was lousy with all 3. It was certainly widely disseminated aviation knowledge, but I realize that doesn't preclude pilots out there making up their own theories that become culture within fenced-off circles, those within convincing themselves it's routine thinking; "This type of wing handles it", "That'll slide off I've seen it before".

Here are some readily-available, published things re winter ops the crew of Palm 90 did know/were paid to know/should have applied if they were familiar with their own Ops Manuals and recommended procedures for thier aircraft at the time of the 1982 accident:

1. FAA regulations. From the report: "The Federal Aviation Regulations are very specific, requiring that "no person may take off an aircraft when frost snow or ice is adhering to the wings, control surfaces, or propellers of the aircraft." The crew knew they had a contaminated wing with frozen precip adhering, yet they took-off it anyway. The Captain made light of the Regs, and yet it's one clearly written in blood long before 1982. Ignorance?..when he said "satisfying the Feds" was he speaking of the act of de-icing but not know that no adhering frost, ice, or snow was the requirement? Or was it feigned, know-it-all parroting of something he'd heard from someone else equally out of their depth. Either way, when they got to the runway they were required to not attempt a takeoff.

2. The Air Florida company Ops Manual mirrored that same Reg, but with relief granted for dry snow if the Captain and person releasing the aircraft agreed conditions precluded adhering. That relief was never sought, and the mod-heavy wet snowy conditions weren't of that nature anyway. So with regards to "clean wing"/contamination", there's no question the crew didn't follow their own Ops Manual either as it existed in 1982. Ignorance of his own Manual?..or disregard for it.

3. Inspection after de-icing. From the Report: "Neither the Air Florida maintenance representative who should have been responsible for proper accomplishment of the deicing/anti-icing operation, nor the captain of Flight 90, who was responsible for assuring that the aircraft was free from snow or ice at dispatch, verified that the aircraft was free of snow or ice contamination before pushback. Ignorance of his own Manual? or disregard for it.

4. Use of reversers. The Air Florida Ops Manual at that time also included Bulletins warning of possible clear ice formation on leading edge devices while using reversers on the ground with snow present. There were also a series of Bulletins and avisories regarding rotation/pitch and roll issues with contamination on the leading edges, and recommended procedures for takeoffs into icing conditions or where contamination may be present. The Captain used the reversers for 30 to 90 seconds at the gate, after de-icing. Ignorance of his own Manual? or disregard for it.

At almost every step where compliance to Air Florida Ops Manual or Regs re winter ops was required there is nothing on the CVR or actions witnessed to indicate the crew was even aware of these requirements, let alone adhered to them. Their actions of using reverse within the confined spaces next to concourse and jetbridge after de-icing was applied, and later trying to position thier aircraft behind Apple's jet blast during taxi to try and melt snow on their own wing, would degrade the minimul anti-ice properties of the de-ice fluid even if that fluid was correctly mixed. These combined, non-approved actions could easily create conditions for ice to form, and this was known information. The F/Os declaration about only needing the inboard portions clean because "with the sweep the rest will slide off after 80" is based on...who knows where he heard that. The Captain's lassaize-faire, non-answer to the F/Os question if there was "anything special" to do for takeoff on that contaminated runway into heavy snow/icing conditions resulting in the F/Os deciding on a "soft field takeoff" solution when there were actual published procedures in their Ops Manual for that situation is another example of apparent ignorance or disregard to applicable procedures.

I mention all this to re-iterate that this crew, on that day and in those particular adverse conditions was virtual green on green. The Captain's experience in bona-fide, winter weather was virtually nonexistant. His previous company, where he had been knocking around south Florida in DC-3s, had been aquired by Air Florida only a few years prior and upgrades were fast. The F/Os commercial aircraft experience in winter ops was even less than the Captains, and his F-15 experience is of dubious relevance..it can fly with an entire wing missing. He exhibited this inexperience by deferring to the Captain's assurances, assurances based on nothing.

Between them there was a big, fat lack-of-experience cheesehole on an unforgiving, wintery day, and in that situation it's critical and incumbent upon any crew to recognize their own limitations and act accordingly. "Accordingly" means conservatively, screwing your flying head down even tighter, and when experience can't guide you the final backstop for safety is strict adherance to Regulation, Manual/SOPs, and applicable recommended procedures for the your specific aircraft. This crew did NONE of those things when faced with conditions unfamiliar to them. They didn't even talk about seeking guidance, and this certainly wasn't one of those rare instances where saving an aircraft means rightfully throwing the Book out. They never had their 1982 Book IN to begin with.

The record shows some of the Captain's proficiency checks went poorly (and failed) due to trouble with the Regs, procedures, systems, and even Limitations of his own aircraft, which is hard to fathom for a new Captain who's nose should be in the books. Those are study-and-preparation issues, and perhaps those subject deficiencies had been rectified, but there's nothing in the Report or CVR to indicate he had prepared himself to gain a working knowledge of his own Air Florida manuals with regards to winter ops, and we heard how seriously he took the regs regarding contamination. Given the series of omissions, non-adherence to Company Policy, and examples of doing things that were known, potential detriments to safety I find it hard to believe the Captain was even aware his Ops Manual contained applicable things he needed to comply with.

"Just to make the Feds happy", "You just need the inboard clear", notions about wing-sweep as it affects shedding..neither of them challenged the other when voicing left-field ideas in areas neither was versed, let alone well-versed in. On the contrary, in both omission and action both exhibited feigned confidence on matters with no experience to draw from, sounding instead like fair-weather pilots revisiting myths told around a Florida crew room campfire back home. The same type of false assurance was exhibited again by the Captain during slow T/O acceleration on a runway aleady accumulating more snow when the F/O raised doubts about it 4 times after mentioning funky engine indications during taxi. Regardless of why it was degraded acceleration, the last chance for the blind to stop leading the blind through a minefield and stopping the show was lost.

You can argue that the de-icing was really icing due to dissimilar mixes and a bad nozzle and that's what caused this accident, it was known that reversers on the ground could cause leading edge contamination, not to mention that swirling your own engine exhaust in the confines next to a concourse and jet bridge would degrade even correctly-mixed de-icing fluid's anti-ice properties or overspray coat. Purposely placing your aircraft into another's jet blast attempting to melt snow accumulations would also ruin any anti-ce properties, and worse, create conditions for re-freezing. Why didn't other aircraft experience the same fate? Those other crews probably weren't using those non-approved procedures or making up their own on the way to the runway that made the situation worse.

You make decent enough arguments on a few points, food for thought anway, but wrapping them in a suggestion that this crew's actions and words represent anything like a barometer of "what was known", done, and disseminated (including to them) re winter ops/contamination/ etc 1982 is a gross misrepresentation. This crew was nothing of the kind, and you whitewashing this crew's inexperience and non-compliance for the sake of focusing on the de-icing issue hints of an agenda.

[Clandestino]

They were not idiots in the medical sense but that they were ignoramuses is beyond doubt.

How could pilots be so ignorant to perform such a hazardous act ? IMHO, first: they have to be ignorant of aerodynamics and meteorology, second: gaps in their knowledge have to be filled by someone delivering his dead wrong message with great detail, patience and perseverance. Higher he be on the airline totem pole, it's easier for him to get the messages such as: "it will be blown off anyway" or "de-icing is useless but satisfies the authorities" across.

Unrealistic theory? Have a look at the last couple of pages on this thread.

[autoflight]

It is easier to inadvertently take-off with ice than generally accepted. As pax in crew bus to stand-off bay I checked surroundings for ice. None on aero bridges, trolleys, various tugs and other vehicles. Couldn't see ice on other aircraft as we drove, or on the tarmac. Nobody was de-icing before departure etc etc. It was a fair bet that there would be no ice on my A321.

I looked for ice during a slow and careful external check. No visible ice. As best able I looked through each open cockpit window at what I could see of the wing leading edges. Looked carefully through the over wing emergency exits and other pax windows. Still no ice. But there was still one duck to line up, so I opened the aft galley door and had a good look at everything I could see from there. About to call it a satisfactory check and decided that while there I would also check the left horizontal stabilizer.

There was sufficient clear ice there to cause concern. In all cases, any is unacceptable. We were critically questioned about our need for de-icing by my culturally conditioned airline, but of course I insisted.

Except for my local F/O, who trusted my decision, there was not a single person who believed we just saved an aircraft and over a hundred lives by insisting on de-icing. The problem with such situations is that the de-ice equipment is not fully staffed, schedule will be disrupted, crew duty hours may be a problem with no replacements available, the cost of the de-ice, and most significantly, the loss of face when competing airlines depart without de-icing.

So while the principle of no ice, holdover times and so on are clear, there are multiple considerations that together conspire to reduce our confidence in the need for de-icing. As pilots, we are absolutely required to follow all the procedures needed to keep our aircraft airworthy.

[AirRabbit]

1. From the report: "The Federal Aviation Regulations are very specific, requiring that "no person may take off an aircraft when frost snow or ice is adhering to the wings, control surfaces, or propellers of the aircraft." The crew knew they had a contaminated wing with frozen precip adhering, yet they took-off it anyway.
Once again – I’ll take the time to point out that both the regulation and persons reading the regulation continually pointed to the word “adhering” with an impression of its meaning that obviously differs from yours. Clearly, you are one of those persons who believe that if snow is on a surface, that fact alone is sufficient verification for you that the snow is “adhering” – but even then you seem to have “widened” the door to allow some other possibilities to sneak through. In one of your earlier posts you said …
If its not wet and glossy but turned opaque, and especially if there's snow present on the fluid surface, the solution has lost the ability to melt frozen precip and absorb/suspend/depress the freezing point of the water. Unless other procedures have been approved in the Ops Specs, the general rule for U.S. air carriers (121.629) if HOT has been exceeded there must be pre-takeoff contamination check accomplished within 5 mins before T/O, and it must be done from outside the aircraft.
While most the above quote is accurate – you haven’t provided any information as to when this language first appeared in the section you cite … and, in a difference from your quote, the actual rule language describes that a takeoff may be made if the maximum holdover time does not exceed that found “in the certificate holder's holdover timetable” – suggesting quite strongly that differing time periods are not only acceptable, but that they do exist – even in the current environment – which, as you know, is substantially more knowledgeable in these areas than what existed 30 years ago.

I’ll also point to your description of some snow where you certainly imply it be allowed on an airplane’s surface…
In any case, no matter how you're trying to parse it, if it's not a dry, feathering snow readily sliding off a cold-soaked wing but is accumulating on it instead, then it must adhering somewhere...
I read that as saying “…if it IS a dry, feathering snow that is readily sliding off a cold-soaked wing … then THAT snow would be allowed to accumulate because it would not be “adhering”… is that what you meant?

…accumulated on de/anti-ice fluid, the fluid has failed (and) this "accumulation" of snow … doesn't meet the criteria "free of" (therefore it is considered) contaminated.
So, by your description, my question would be … just exactly how long after a snow flake falls on a surface that has had a coating of anti-ice fluid applied would that snow flake be rendered to a state of a harmless fluid? Equally important, does the rate of snow fall have any impact on this process? I’m just wondering, under your conception of the process, how it is that an airplane is allowed to takeoff during a falling snow?

2. The Air Florida company Ops Manual mirrored that same Reg, but with relief granted for dry snow if the Captain and person releasing the aircraft agreed conditions precluded adhering. That relief was never sought, and the mod-heavy wet snowy conditions weren't of that nature anyway. So with regards to "clean wing"/contamination", there's no question the crew didn't follow their own Ops Manual either as it existed in 1982. Ignorance of his own Manual?..or disregard for it.

And

3. Inspection after de-icing. From the Report: "Neither the Air Florida maintenance representative who should have been responsible for proper accomplishment of the deicing/anti-icing operation, nor the captain of Flight 90, who was responsible for assuring that the aircraft was free from snow or ice at dispatch, verified that the aircraft was free of snow or ice contamination before pushback. Ignorance of his own Manual? or disregard for it.
You “say” that relief was never sought … you say that no one verified that the aircraft was free from snow or ice … obviously you are not aware that it was the Captain (in coordination with the company maintenance supervisor on duty ... to some degree) who was responsible for “releasing” the aircraft? According to the Accident Report (page 3) “…the same American Airlines mechanic that had inspected both engine intakes upon completion of the deicing/anti-icing operation performed another general examination of both engines. He stated that he saw no ice or snow at that time. Air Florida and American Airlines Personnel standing near the aircraft … stated that they did not see any water, slush, snow, or ice on the wings.”


4. Use of reversers. The Air Florida Ops Manual at that time also included Bulletins warning of possible clear ice formation on leading edge devices while using reversers on the ground with snow present. There were also a series of Bulletins and avisories regarding rotation/pitch and roll issues with contamination on the leading edges, and recommended procedures for takeoffs into icing conditions or where contamination may be present. The Captain used the reversers for 30 to 90 seconds at the gate, after de-icing. Ignorance of his own Manual? or disregard for it.
And you admonish me for “cherrypicking?” Come on, sir … let’s be fair. While it is correct that the Ops Manuals very likely discussed the kinds of things you say – did you possibly check to see where in the manual such statements were made. For example, in discussing the arrival of a flight into a terminal area during snow conditions, that same manual said the following – also quoted from the Accident Report:
A buildup of ice on the leading edge devices may occur during ground operations involving use of reversers in light snow conditions. Snow is melted by the deflected engine gases and may refreeze as clear_ ice upon contact with cold leading edge devices. This buildup, which is difficult to see, occurs in temperature conditions at or moderately below freezing. Crosswind conditions can cause the ice buildup to be asymmetrical, resulting in a tendency to roll at higher angles of attack during subsequent takeoffs.
I’m sure you know of the problems that may be caused by landing on a snow-covered runway, stopping with the use of up to and possibly including full reverse thrust (which as you know throws anything on the ground – like water or snow – forward of the airplane and likely impinges on that airplane as it moves forward. Additionally, taxiing in to the gate after landing, a flight crew may well use reverse thrust to assist braking effectiveness. The quote you provided is almost always read in the context of a “between approach – through the landing – taxi in – and parking sequence.” This why the quote you provided clearly describes problems that may be encountered with “subsequent takeoffs.”

In your incessant arguments that this situation was complicated by a couple of bafoons to knew little and cared less. You continue to cite what you believe was a deliberate maneuvering of their aircraft to be “deiced” by the jet blast of a preceding airplane. I hope to goodness that you are never recorded, in a moment of utter frustration, uttering a hyperbole (such as “I’d sell my oldest child for a parking place!) because someone with your penchant for not understanding the potential uses of such parts of speech in, at least the Americanized version of, the English language is going to think you more than just a bit nuts – when those of us here have come to recognize that you are certainly not nuts.

While we are looking more carefully at the contents of that company’s Ops Manual, it might interest you know that the following was contained in that manual as well – as prescribed by the airplane manufacturer (again, from the Accident Report, page 37)

Section 3A-7, page 2, of the August 20, 1973, issue of the B-737 Operations Manual, Supplementary Procedures, Ice and Rain Protection, “Wing Anti-ice,” states: There are two methods recommended for operating the anti-icing. The primary method is to use it as a deicer, by allowing the ice to accumulate before turning it on. This procedure will provide the cleanest airfoil surface, the least possible runback ice formation, and the least thrust and fuel penalty. Normally, it will not be necessary to shed ice periodically unless extended flight through icing conditions is necessary (holding). Ice less than 3 inches thick will have little effect on airplane handling, therefore, the ice accumulation may be allowed until the icing condition has been passed. The secondary method is to turn the wing anti-ice switch on when wing icing is possible and use the system as an anti-icer.

I’ll just leave that manual paragraph alone for anyone’s contemplation.

You can – and you have – criticized these crewmembers quite heavily – they and their families paid – quite heavily for any mistakes they may have made – certainly relying on what and how they were trained, relying on a competent ground crew to deice and anti-ice their plane – doing what everyone else that day appeared to be doing – wasn’t all a mistake.

Do I have an agenda? You bet. And I thought I made that perfectly clear in my first post on this thread. The reason I interjected my original comment into this thread was not to start an unwanted argument about what should have been done or what the flight crew should have known and did know. My original comment was to correct what I saw as an incorrect impression that it was a the low engine takeoff power that caused the accident. The NTSB officially, and at least one NTSB participant (quoted by one of the posters here) collectively agreed that the engine power setting did not cause that accident. The NTSB reached the conclusions they reached. Some of us in the aviation world disagree with those conclusions … welcome to the world of individuality. There will inevitably be doubts and incomplete knowledge in almost any accident scenario … and I sincerely believe THAT is the primary reason that the NTSB does not publish “Accident Causes.” They publish “Probable Causes” of accidents. Do I expect the conclusions reached in this accident to be changed? …not hardly! Does that mean I agree with all that was said in that report? …again, not hardly!

One thing I hope I am never caught doing is besmirching the reputation of fellow aviators that have experienced unfortunate turns of events. I’ll leave the allegations of “lack of awareness;” of “providing Laissez faire ‘non-answers’ to questions;” and the like to others. I would hope that any professional on this or any other forum, or in any other exchange of philosophy or ideas or questions, will examine all there is to examine – including the concerns, opinions, and beliefs of others – not to the exclusion of facts, but perhaps to bring slightly differing highlights to those facts … to better understand and appreciate what happened …and then do all they can to learn from what those actions have provided.

[AirRabbit]

They were not idiots in the medical sense but that they were ignoramuses is beyond doubt.

How could pilots be so ignorant to perform such a hazardous act ? IMHO, first: they have to be ignorant of aerodynamics and meteorology, second: gaps in their knowledge have to be filled by someone delivering his dead wrong message with great detail, patience and perseverance. Higher he be on the airline totem pole, it's easier for him to get the messages such as: "it will be blown off anyway" or "de-icing is useless but satisfies the authorities" across.

Unrealistic theory? Have a look at the last couple of pages on this thread.
I'm going to side-step the opportunity to respond in "like manner" ... as I've made the points that I believe are relevant and I'm quite comfortable in having done so. It's up to each reader to determine the level of competence and accuracy they wish to attach to each. I wish you all a comfortable coming week!

[sabenaboy]

I have carefully read your contributions and your analysis of the Air Florida crash and I took the time to read (parts of) the NTSB report. Your knowledge about this case is impressive and so is the polite language that you use while telling your side of the story. Not that it matters, but just for the record: you have convinced me. What you are saying is very plausible indeed. I would however respectfully like to suggest you to stop arguing with some of the members on this topic, simply because it's a waste of time. You said what you needed to say and did it very well. :ok:

[AirRabbit]

I ... respectfully ... suggest you stop arguing with some of the members on this topic, simply because it's a waste of time. You said what you needed to say and did it very well.
Thank you for the very kind remarks ... and for the excellent advice ... which I had previously considered doing ... but will now adopt.

[mercurydancer]

Air Rabbit

For my two cents.. (or kopeks)

A well reasoned discussion is always welcome. I appreciated your comments.

[Clandestino]

I’ll just leave that manual paragraph alone for anyone’s contemplation.

The manual paragraph you have quoted is referring to inflight icing. What it has to do with attempted takeoff with ice contamination of the upper wing surface, accrued during ground operations, which happens to be the subject of the thread?

My original comment was to correct what I saw as an incorrect impression that it was a the low engine takeoff power that caused the accident. The NTSB officially, and at least one NTSB participant (quoted by one of the posters here) collectively agreed that the engine power setting did not cause that accident.
There is no dissenting opinion included in the NTSB report. NTSB is pretty clear that too low power did not cause the accident on its own but that without it, the catastrophe would not have happened: The aircraft could not sustain flight because of the combined effects of
airframe snow or ice contamination which degraded lift and increased
drag and the lower than normal thrust set by reference to the erroneous
EPR indications. Either condition alone should not have prevented
continued flight. The story about NTSB member disagreeing with it comes from the anonymous poster on the anonymous forum where every post comes with caveat:
As these are anonymous forums the origins of the contributions may be opposite to what may be apparent. In fact the press may use it, or the unscrupulous, or sciolists*, to elicit certain reactions.

The NTSB reached the conclusions they reached.As presented, it is a perfect tautology. However, NTSB has quite comprehensively documented the method of getting to conclusions, while on the other side...

Some of us in the aviation world disagree with those conclusions … welcome to the world of individuality. ...most of those disagreeing with NTSB conclusions just say it-was-not-so, without further reference or with unverifiable reference at the best. Every individual is entitled to his own opinion but in my humble opinion that no one is entitled to his own set of facts should not be debatable.

We all know that stall warning won't occur (in ice-contamination case) when actual stall happen because system does not measure disturbed air flow and contamination on wings. Actually, we shouldn't be knowing that. The effect of ice contamination is dependent on so many variables that it is impossible to quantify it except in the postmortems. In Air Florida 90 case, Cd was affected far worse than AoAcrit, so the crew got the stickshaker before stalling - which combined with misplaced belief that stall always comes before stickshaker when wing is contaminated resulted in some wrong theories. What you referred to is worst case scenario while the best case contamination scenario happens any given snowy day; certification margins are not entirely eaten up at half-the-wingspan height and aeroplane happily flies away.

Can they for instance command pitch that is in excess of reduced critical AOA? They can command the pitch that would lead to flight path that would lead to AoA exceeding AoAcrit of contaminated wing, however, chances for such adverse contamination combined with low V2 are very slim. "Pilots" have to determine how lucky they feel. Pilots de-ice and anti-ice if needed but do their best to ensure nothing except de-cing fluid is on their wings as they push the thrust levers far forward. Wordgames such as the exact meaning of "adherence" and "takeoff" don't come into play.

[Crabman]

Frankly, I find AirRabit's analysis and comments very persuasive. I appreciate them very much.

Question: Given that most accidents involve a chain of causal elements ("but for ..." the accident wouldn't have happened), why elevate one (or more) to be the "probable cause" and relegate the rest to "contributing to"?

I know the NTSB may be charged by statute to do this, but does it really make sense? I believe that other jurisdictions (Canada?) just identify the causal elements and don't attempt to elevate any to being "THE Cause"?

Last point. It is called the "probable cause", not the "proven cause". So why the vitriol when someone posts a dissenting opinion?

[M.Mouse]

There is no dissenting opinion included in the NTSB report. NTSB is pretty clear that too low power did not cause the accident on its own but that without it, the catastrophe would not have happened:

So how do you answer AirRabbit's conjecture that the B737 characteristic for alarming and uncontrollable behaviour with leading edge contamination possibly occurred and all that greater thrust would have achieved would have been that the aircraft and its occupants would have reached the point where the tragedy was inevitable marginally quicker?

Addressing that one point would be appreciated, my apologies if I have missed where you have addressed it.

[AirRabbit]

There is no dissenting opinion included in the NTSB report. NTSB is pretty clear that too low power did not cause the accident on its own but that without it, the catastrophe would not have happened
With my respectful apologies to sabenaboy after having agreeing to take his very appropriate and very worthwhile recommendation … I feel one last rebuttal may be in order.

Of course there is no “dissenting opinions included IN the NTSB report … that’s not what NTSB reports do … but that doesn’t mean that there are NOT a large number of aviation professionals who have dissenting opinions about what that report says. As the investigation revealed (and referenced here) the “low power setting” of the engines did not cause the accident” … but the only way an airplane could have continued flight – even with all the power both engines were capable of producing - would have been if the attitude of the airplane was such that the engines – even at Max Thrust – could have pushed the airplane through the air at the attitude achieved at that time. Recall the video of the F-100, with the afterburner lit? Recall it wallowing through the air prior to impact? … this was THE specific event that generated the term “Sabre-dance.” That F-100 SuperSabre was at a pitch attitude that even with the A/B blasting everything under it into small dust particles – there was insufficient thrust to push that airplane in the direction opposite to that thrust. So too was that B-737 … the pitch attitude of that B-737 – caused by the uncontrolled pitch-up caused by the incorrect deicing/anti-icing procedures applied – was such that all the thrust of both those engines – and I don’t care what power setting they could have selected – would have resulted in exactly the same end … just like what occurred to that F-100 SuperSabre. Just in case you forgot, jet engines produce thrust to push the airplane in the direction opposite to that thrust vector – nothing more – nothing less. With any thrust, an airplane would be able to be pushed only in the direction opposite to that thrust direction. In both of these cases, the F-100 and the B-737 … there wasn’t enough thrust capable of being generated even with the added thrust of the A/B in the F-100 case … even with full power, maximum power, throttles-bent-over-the-fire-wall power in the B-737 case – there wasn’t enough thrust to push the airplane “forward” sufficiently to achieve sufficient lift to maintain flight. And, before someone points out that "they did it in a simulator." Yeah. I know something about simulators as well ... and given the right knowledge and time at the simulator's input keyboard, I can make a Cessna 152 simulator "fly" just exactly like the space shuttle.

So how do you answer AirRabbit's conjecture that the B737 characteristic for alarming and uncontrollable behaviour with leading edge contamination possibly occurred and all that greater thrust would have achieved would have been that the aircraft and its occupants would have reached the point where the tragedy was inevitable marginally quicker?

Addressing that one point would be appreciated, my apologies if I have missed where you have addressed it.
This is probably the “question of the thread,” thanks, M.Mouse!

As I pointed out … way back on April 17th in post #276 …

I believe that once this crew pushed the throttles forward with the intent to takeoff, they were doomed. The only way that an accident could have been avoided at that point, was to have kept the airplane on the ground until a sufficiently higher airspeed was reached prior to initiating the rotation. Unfortunately, not only did the crew not know that this would be necessary, they wouldn’t have known the “magic” airspeed number. Even if they had pushed both throttles all the way to the firewall from brake release, and then rotated at the computed rotation airspeed (as they did) the airplane would have performed in exactly the same way. It would have uncontrollably pitched up to at least the 22 – 24 degree attitude; likely more given witness statements … where some said they saw “the aircraft was flying at an unusually low altitude with the wings level at a nose-high attitude of 30 degrees to 40 degrees before it hit the bridge.” It would have entered the same deep aerodynamic stall. The flight crew would have been unable to bring the nose down aerodynamically. Unfortunately, in that condition, full thrust on both engines would have been insufficient to maintain flight. All who were affected by this tragedy were victims of longitudinal differential lift. The flight crew did not have the luxury of time to analyze, consider, and choose accordingly.
Had this B-737 flight crew kept the airplane on the ground until achieving a forward speed sufficiently high to have produced lift even somewhat evenly along the entire length of both wings – the asymmetrical longitudinal lift components may have been small enough that the pilots could have maintained control. However, when the F/O brought the control column back to a neutral position – in anticipation of rotating at the computed "rotation" speed (however he was planning to rotate – to whatever attitude he planned to rotate) – the airplane took over … snatching the pitch control completely away from that pilot and taking that airplane up to an attitude that achieved a rather severe stall buffet only 3 seconds after having all three gear (the nose and both mains) on the runway. THAT was the reason the Captain was recorded as saying - at THAT specific time ... "Easy!" Conservative estimates say that the stall buffet wouldn’t have been reached until the pitch of the airplane achieved something like 24 degrees – so, the pitch attitude was at least that high. Some witnesses (forming angles with their hands when specific numbers made no sense to them) indicated to investigators that the airplane may have been at an attitude of more than 40 degrees nose up. Think about that for a minute … 40 degrees nose up! With the airplane's forward momentum (which is what got it from the runway to the 14th Street bridge - it certainly didn't "fly" there) it’s almost anyone’s guess as to what Angle of Attack was actually achieved. So ... was it possible for that crew to make that B-737 "fly" at that pitch attitude ... with that AoA ... with a measley additional 15-20% thrust? Not at that kind of airplane attitude – talk about “son-of-Sabre” … as I said previously, an Atlas Booster would have had problems getting that airplane to "fly."

For Reference:
Aviation Video: F-100 test flight crash (Sabre Dance) | Patrick's Aviation (http://www.patricksaviation.com/videos/popejoshpope/1522/)

[Clandestino]

So how do you answer AirRabbit's conjecture that the B737 characteristic for alarming and uncontrollable behaviour with leading edge contamination possibly occurred and all that greater thrust would have achieved would have been that the aircraft and its occupants would have reached the point where the tragedy was inevitable marginally quicker?

How could I possibly answer that? I am not an aerodynamicist familiar with 732. Heck, I'm not even rated on her, but I can easily find an expert opinion on the matter:

The Safety Board concludes that neither the low thrust used during the takeoff
nor the presence of snow or ice on the aircraft, alone, would likely have led to the crash.
In most other reported incidents in which B-737’s have pitched up during takeoff, the
flightcrews had sufficient control authority with forward control column force and
stabilizer trim to overcome the pitching moment, reduce the pitch attitude, accelerate
to a lower angle of attack, and climb out successfully. The Safety Board believes that if
the proper thrust level (that for 2.04 EPR) had been used for the takeoff this flightcrew
could have recovered from any difficulties caused by the contamination - induced
aerodynamic performance penalties.
Furthermore, based upon the engineering simulation, the Safety Board
concludes that even with the low thrust during the takeoff roll and the aerodynamic
penalty of the snow or ice contamination, the accident was not inevitable as the aircraft
lifted off. However, both immediate recognition of the situation and positive effective
actions by the flightcrew to both counter the noseup pitching moment and add thrust were
required. With these actions, the aircraft should have been capable of continued
acceleration and achieved a sufficient performance margin for climbout.


The engineering simulation of Flight 90’s flight profile disclosed that the aircraft’s rate of acceleration after liftoff, below normal
because of the reduced thrust, was further impaired by a high noseup pitch attitude attained during the takeoff rotation.

Consequently, the aircraft did not reach an airspeed
safely above the stall speed. The high pitch attitude occurred because the flightcrew
failed to, or was unable to, react quickly enough to counter the aircraft’s longitudinal trim
change produced by the wing leading edge contamination. The reports since 1970 by other
operators who have experienced abrupt pitchup or rol off immediately after liftoff of
B-737 aircraft indicate that the B-737 may have a greater known inherent pitchup
characteristic than other aircraft in this regard a result of small amounts of frost, snow,
or ice on the wing leading edge. The Safety Board could not determine whether the
aerodynamic design makes the B-737 more sensitive to pitching or rolling moments when
the wing is contaminated, or whether more frequent operation of these aircraft in
environmental conditions conducive to snow or ice accretion during ground operations,
coupled with the near to the ground wing placement, accounts for the higher number of
reported B-737 pitchup/rolloff incidents, Regardless, the Safety Board concludes that the
pitchup tendency of the aircraft because of leading edge contamination contributed to the
accident. However, to place this contributing factor in perspective, the Board notes that no
aircraft design requirements include the ability to perform with snow or ice
contamination and that any known contamination, regardless of the amount or depth, must
be viewed as potentially critical to a successful takeoff. For this reason, flightcrews are
not only dissuaded, but are prohibited, from attempting a takeoff with such
contamination.


Hope this helps. The report goes into great detail how the conclusions were made.

So how come some PPRuNers get convinced by the theories that are at odds with the expert analysis and have no traceable source? PukinDog nicely analyzed one such contribution:

You make decent enough arguments on a few points, food for thought anway, but wrapping them in a suggestion that this crew's actions and words represent anything like a barometer of "what was known", done, and disseminated (including to them) re winter ops/contamination/ etc 1982 is a gross misrepresentation. This crew was nothing of the kind, and you whitewashing this crew's inexperience and non-compliance for the sake of focusing on the de-icing issue hints of an agenda.

The picture certain poster has painted has some true details, some true yet grotesquely exaggerated, some completely irrelevant, some that are so-pulled-out-of-the-thin-air they cannot be verified at all and some brazenly false. When the details are put together the composition reveals what was the message (original term was "the truth") that the contributor wanted to get through: the poor, hapless crew was tragically betrayed by almost everyone. They were betrayed by the de-icing crew that poured water instead of glycol mixture on their wing. They were betrayed by FAA by not having developed the holdover times at the time. They were betrayed by the Boeing co designing the aeroplane that would pitch-up when stalling with iced leading edge. They were betrayed by the ATCO using too little spacing between them and landing Eastern. Basically, it was everyone else's fault, they were just the one who died. There was nothing they could do. They were doomed.

Realistic picture, eh? Not at all. So how come it is believable? Basic HF: people are convinced of something because they want to be convinced. If reading the accident report pages where crew's mistakes are neatly explained fills you with horror and, despite the facts, you want to believe that QH90 (or any other) crew did their best but it was tragically insufficient, to sooth your anxiety you would do well to listen to alternative theories of e.g: de-icing with water, composite fins being weaker than metal ones or Airbus cockpit being a deathtrap by design.

However, if you are into learning something from mistakes of others, lest you repeat them, it's far better to read and understand what is written in the official accident report. Stress is on understanding as it will help you recognize skewed reports produced under undue political pressure or when the good report is unduly smeared as false.

Whatever suits you, terms of the PPRuNe use do not preclude going whichever path you choose. Outcomes might differ, though.

[DOVES]

I cannot refrain from intervening because it can be deadly for your seeds to sprout.
"Quousque tandem abutere, AirRabbit, patientia nostra?"
You know me and the pulpit my words come from.
Can I say the same of you?
I don’t think you’ve ever been (sitting at the front row of a plane and not in front of a 6-Drawer Oak desk) in such a situation:
Typical winter night in Europe, about to leave from an airport during a dreadful snowstorm.
In addition to the usual procedures we had to:
- Take a place in the queue for the de-icing
- Wait every few tens of minutes for the runway in use and taxiways to be cleared from snow.
- Based on the estimated time of completion of the aforementioned procedures, request a slot for departure.
- Calculating the synchronization of all of that to determine if and when to surrender to the pressure of ramp agent who wanted the passengers to be embarked.
I had long since given up the scheduled departure time.
It's obvious that it was wishful thinking to have all the above operations completed all together.
If the runway had been cleared, the plane was not yet being deiced / anti-iced, or vice versa, or the slot provided had expired and reassigned half an hour later, and then we had to go back to the starting point.
If the passengers had boarded, we had to invite them to remain on board for not losing the priority acquired; maybe we prayed the flight attendants to serve a refreshment.
Finally everything was ready to start (there was a tyrannical "holdover time"), but not without having alerted the Purser not to hesitate to advise if he saw some snow on the wings.
And then:
There were conditional procedures to apply: special operations, "Cold Weather Operations" and "T.O. and Landing on Contaminated Rwys ".
They had to be performed, with the contribution of PF and PNF; a flight controls test at the beginning and at the end of taxi, a test of extension and retraction of the flaps / slats, the activation of Engine Anti-ice (with engine run-up every ten minutes to remove any ice formed on the intake of the engines and on PT2 probes), and the predisposition of the Airfoil anti-ice, after start.
After rotation we were expected to cycle the “retraction / extension / retraction” of the landing gear in order to shake any slush from it.
It's absolutely clear that avoiding all of this fuss would make life much more easy, and I confess that more than once I found myself in the embarrassing
position to explain to a passenger of mine stating: "That guy did not perform the deicing and is going, while we are having such a delay ... "
My answer: "Safety is our first goal."
CONTAMINATION ON ANY PART OF THE AIPLANE: NO GO!

[mercurydancer]

"It's absolutely clear that avoiding all of this fuss would make life much more easy, and I confess that more than once I found myself in the embarrassing
position to explain to a passenger of mine stating: "That guy did not perform the deicing and is going, while we are having such a delay ... "
My answer: "Safety is our first goal."

If anything is going to be learnt from the vid of the flight from SVO its that us passengers are far more likely to accept your explanation than was so even a few months ago.

[AirRabbit]

When M.Mouse asked about the B737 characteristic for alarming and uncontrollable behaviour with leading edge contamination, you answer with …
How could I possibly answer that? I am not an aerodynamicist familiar with 732. Heck, I'm not even rated on her, but I can easily find an expert opinion on the matter:
…and you come up with the following??

(NTSB AAR82-08, page 54) “In most other reported incidents in which B-737’s have pitched up during takeoff, the flightcrews had sufficient control authority with forward control column force and stabilizer trim to overcome the pitching moment, reduce the pitch attitude, accelerate to a lower angle of attack, and climb out successfully.”

The NTSB’s words (not mine) … “in most other reported incidents … the flightcrews had sufficient control authority…” Most? What about the other incidents? Just how many “other incidents” were there? Did any of those other incidents include an absence of control authority? What happened in THOSE cases?

(NTSB AAR82-08, page 54) “The Safety Board believes that if the proper thrust level (that for 2.04 EPR) had been used for the takeoff this flightcrew could have recovered from any difficulties caused by the contamination – induced aerodynamic performance penalties.”

and

(NTSB AAR82-08, page 52) “If the flightcrew failed to, or was unable to, counter the pitchup moment of the aircraft with sufficient forward control column force, the aircraft could become airborne at an excessively high pitch attitude. The aircraft would not accelerate and it would retain a high angle of attack and high drag.”
So the “expert opinions” you settle on are these? Do you have an opinion on which of these diametrically opposite expert opinions is the one you care to believe? … which is it? …The crew could have recovered but failed to do so … or … the crew was unable to recover? Did you flip a coin … or are you prejudiced and don’t want anyone to know?

While I will stop way short of claiming to be an aerodynamic expert on the B-737-200, I am rated on the B-737 and I do have considerable time in the -200 series aircraft (even more in other makes/models … despite some here, like Mr. Doves, who choose to disbelieve my “profile” information – which, of course, is their – his – individual choice – even if, however self-serving it may seem to others to be, I will continue to believe that I am my own best judge of my own knowledge and experience.) … it is my contention that the NTSB selected a “middle-of-the-road” response by saying (see NTSB AAR82-08, page 68) “The reports since 1970 by other operators who have experienced abrupt pitchup or roll off immediately after liftoff of B-737 aircraft indicate that the B-737 may have a greater known inherent pitchup characteristic than other aircraft in this regard a result of small amounts of frost, snow, or ice on the wing leading edge. The Safety Board could not determine whether the aerodynamic design makes the B-737 more sensitive to pitching or rolling moments when the wing is contaminated, or whether more frequent operation of these aircraft in environmental conditions conducive to snow or ice accretion during ground operations, coupled with the near to the ground wing placement, accounts for the higher number of reported B-737 pitchup/rolloff incidents, Regardless, the Safety Board concludes that the pitchup tendency of the aircraft because of leading edge contamination contributed to the accident.”

It sounds as though the NTSB recognizes that it’s not as damning to accuse a system or design feature of an airplane as having contributed to an accident as it is to say that particular system or design feature actually caused an accident. Libility … cost … reputation … etc., get to be really stupifyingly large issues that no one in a political arena would be willing to challenge. Now, I suppose you’re going to tell us that government officials don’t protect themselves and their organizations when they believe that is the proper or prudent thing to do … sure … we all know that.

Contrary to Clandestino’s claim that “a certain poster” (could he possibly have meant someone other than me?) has submitted “…some true details, some true yet grotesquely exaggerated, some completely irrelevant, some that are so-pulled-out-of-the-thin-air they cannot be verified at all and some brazenly false.” With the amount of information I’ve posted – I’ll not offer an all-encompassing denial … but I will – and I do – deny that anything I’ve posted is knowingly wrong, knowingly inaccurate, knowingly exaggerated, knowingly irrelevant, and certainly NOT “brazenly false.” To the contrary – everything I’ve posted has been relevant – or I wouldn’t have posted it (still don’t understand that accusation) … some of what I posted is directly from our friends at the NTSB – everything I posted is, to the very best of my professional knowledge and training, is true … at least as the facts that support them are true, without any exaggeration or limitation – and nothing – absolutely nothing in any of my posts was “pulled-out-of-thin-air” – and were I not trying to keep this discussion on a civil level (for everyone and everything concerned) that kind of comment could have been taken in a way that, had it been offered personally in the local pub – there is at least a reasonable chance that both of us would have been taken away – one to a local medical facility and the other to a local constabulary – and I would have hoped he had resilient recuperative abilities. While some here may think lying to be an acceptable, perhaps even an expected, part of this business, but I don’t … I don’t lie, I don’t expect others to lie, and I particularly don’t appreciate being accused of doing it. If anyone here can point to anything that I’ve posted about which you have legitimate concerns as being untruthful or inaccurate in any way… please let me know and I’ll do my very best to provide whatever additional facts, theories, reports, or other information that may be appropriate to rectify that issue – but, as many of you know here, I’ll stop short of providing information that may give away my identity. As I’ve repeated here often … if my employers knew of my participation, I’d likely get an opportunity to refer to them as my “former” employers – and that is a step I’m not quite ready to make – it also requires me to be a bit more informative in my posts – as you would then either agree or disagree based on the merits of what I post and not be tempted to agree or disagree with me because of the positional authority I may hold. For example if I were a senior NTSB investigator – you might tend to believe me more – but my bosses on the Board might think I’ve overstepped my agreed-to responsibilities and other oaths I may have taken.

What I continue to find hard to believe is that throughout history professional aviators have not appreciated the label of “pilot error” that gets affixed to more than a fair share of difficult to analyze accident or incident situations. Sure pilots make errors – even very good pilots make errors – I’ve certainly made my fair share – perhaps more than my fair share. Sometimes errors wind up contributing to or causing accidents or incidents - sometimes they do not. Sometimes accusations are true and accurate … sometimes they are not.

Mr. Clandestino alleges that I (he uses the term “contributor” – hmmm … wonder if there is a sinister concern for being caught in a slander?) believe that the crew “was betrayed” by a whole series of people and events – concluding by stating that “…people are convinced of something because they want to be convinced…” and even describes the flight crew as “poor and hapless … tragically betrayed by almost everyone.” An aside here, for a moment … it is clear that Mr. Clandestino understands, or at least rather easily uses, “figures of speech” in his communications … where the particular figure of speech he chooses to use here, described as “irony,” is used in his description of the crew here … where, clearly, he says one thing but the intent is clearly to convey the opposite thing - that the crew members are not “poor and hapless” and were not “tragically betrayed by almost everyone.” For everyone’s benefit, the use of an “ironic” statement, as defined in most English textbooks, is the following: “Irony - the use of word/sentence in a way that conveys a meaning opposite to its usual meaning.” Some here may recall the allegation made that the flight crew deliberately taxied behind a preceding airplane to “get his wings deiced.” And they based that on a CVR transcript that read, as I recall “Don’t do that Apple, I need by other wing done.” Is it so out of bounds to even remotely consider that the intent of this statement would also be an ironic statement? As the definition says … “the use of word/sentence in a way that conveys a meaning opposite to its usual meaning.” As an exercise, try tape recording your next departure from engine start to level off and see if, or how many times, you and your “mates” use Ironic statements to punctuate or add to the conversation. It just might scare you to realize that what you said, would be what everyone would hear if you were to die in a subsequent crash of that airplane.

He apparently does not believe that the flight crew was “…betrayed by the de-icing crew that poured water instead of glycol mixture on their wing.”
Well – what did the de-icing crew pour all over the airplane? According to the NTSB report the airplane “…was deiced with 100 percent water and the final overspray was applied with a 20 to 30 percent deicer to water solution selected. Subsequent tests of deicing fluid/water solution taken from the Trump vehicle showed that the mixture dispensed differed substantially from the mixture selected. The percent of deicing fluid in solution was about 18 percent rather than 30 percent.” A fact that was also revealed during the tests conducted on the Trump vehicle but not included in the NTSB report, was that the mixture of 18 percent (rather than 30 percent when that value was selected) was measured at nominal, or close to zero, flow rate. The content with any additional flow rate was extracted almost exclusively from the water tank and virtually none from the glycol tank. The specific numbers were not available as the flow rate “pulsed” with the RPM of the drive pump and there was the residual amount of glycol present at the nominal flow rate. At the completion of the test, it was evident that the volume in the water tank was lowered by approximately the amount calculated for the time additional flow rates were used, but the volume in the glycol tank was not appreciably changed during this period of increase flow rate.

He apparently does not believe that the flight crew was ”… betrayed by FAA by not having developed the holdover times at the time.
I’m not sure of this reference, as there is no mention of “holdover times” or “HOT” in the Accident Report anywhere that I can find. Perhaps he could provide all of us with a reference for his thoughts on this issue?

He apparently does not believe that the flight crew was ”… betrayed by the Boeing co designing the aeroplane that would pitch-up when stalling with iced leading edge.”
Let’s see about this one:
NTSB Report Page (ii) “…the known inherent pitchup characteristics of the B-737 aircraft when the leading edge is contaminated with even small amounts of snow or ice…”
NTSB Report Page 1 “…the known inherent pitchup characteristics of the B-737 aircraft when the leading edge is contaminated with even small amounts of snow or ice…”
NTSB Report Page 34 “…Since 1970 there have been a number of reports by operators of B-737 aircraft, who have experienced an aircraft pitchup or rolloff immediately after takeoff in weather conditions which were conducive to the formation of ice or frost on the wing leading edges. The Safety Board is aware of 22 such reports during the period.”
NTSB Report Page 35 “…The continuation of reports of pitchup/rolloff occurrences prompted The Boeing Co to examine further the B-737 aircraft sensitivity to leading, edge contamination. In 1977 plans were formulated for wind tunnel and flight tests. Even before conducting these tests, The Boeing Co. on February 23, 1979, issued Operations Manual Bulletin 79-2 to advise flightcrews of a possible inadvertent pitchup/rolloff after takeoff due to ice accumulation on leading edge devices. The bulletin stated that several operators of B-737’s had reported pitchup and/or rolloff after takeoff caused by ice accumulations on leading edge devices and that such incidents had usually occurred following the application of reverse thrust while taxiing on snow-covered taxiways.
NTSB Report Page 35 As part of its investigation of the reported incidents, The Boeing Co. flight tested a B-737-200 advanced airplane in the fall of 1980 to quantify the aerodynamic effects of contaminated leading edge slats. The leading edge slats were coated with an epoxy potting compound and the surface was roughened with a paint roller to simulate a coating with corn ice. A series of stalls was conducted with flaps up, and at flap positions of 1, 15, and 40. The stall characteristics with both symmetric and asymmetric leading edge contaminations were characterized by a very apparent pitchup, yaw rate, and rolloff. These characteristics were more pronounced at flap settings less than 5…

OK. OK. I think you get the picture. Betrayed? Maybe? If YOU were flying an airplane that had these kinds of “known” tendencies … and knew that they had occurred more than 20 times … would you like to know?

He apparently does not believe that the flight crew was ”…betrayed by the Air Traffic Controllers using too little spacing between them and landing Eastern.”
Well, it is true that the accident flight was cleared onto the runway at 1558:58. Subsequently, they were cleared for takeoff at 1559:24. Those times don’t look too “pushed” until you realize that there was moderate snow falling throughout this time – and the taxiways and the runway had some accumulation. Do you taxi from a snow-covered taxiway onto a snow-covered runway using the same techniques you would use if the taxiway and runway were clear and dry? Of course not! Is everyone aware that the tower controller could not “see” the approach end or the departure end of the runway at that time? So, maybe we can see if they were “betrayed” by looking again at the CVR transcript:

1600:03 LC Eastern fourteen fifty-one, the wind Is zero one zero at one one you're cleared to land runway three six, the visual range touchdown two thousand elght hundred rollout one thousand six hundred/
1600:04
1600:05 CAM-2 Ah, that's not right
1600:06
1600:07 CAM-2 (Well) ---
1600:08
1600:09 CAM-1 Yes It is, there's eighty
1600:10 CAM-2 Maw, I don't think that's right
1600:11 E451 Fourteen fifty-one cleared 'to land over the lights

Now, I should point out (not that you weren’t aware of it – just reminding everyone) that one of the difficulties in reading a CVR transcript and understanding what took place just prior – during – or just after any point on that transcript is not recognizing that some things are said in a second or less … other things take a bit longer to say … for example … the Local Controller’s clearance to EA1451. It’s on the CVR Transcript as having been said at 1600:03. Try reading that statement and see how long it takes. Also, you have to know that controller had to view his “bright” scope, the indications for wind speed and direction … and … make that radio call. Was all that done in 1 second? I doubt it … in fact, I suspicion that as the Local Controller unkeyed his microphone after issuing the landing clearance, the Eastern pilot immediately responded – even though the time of that radio call is shown to be at 1600:11 – fully 8 seconds after the Transcript indicates the time of the clearance being issued. Throughout this Eastern-Tower exchange the accident flight crew was busy making a takeoff.

Don’t let me put thoughts into your head – you decide. You’re the Captain on the B-737. You’ve received clearance onto the runway, taxied out, begun the line-up turn, pushed up the throttles to get the engines spooled … the F/O takes control of the airplane. He further spools the engines up toward TO EPR setting – what are you watching? The throttle position? … the engine EPR gauges?… the centerline of the runway? Your F/O sets what he believes is or is close to TO EPR and you prepare to take over monitoring of the throttles. At that time, he says something like “Geeze – look at that thing? That don’t seem right, does it?” Where do you look to see what he’s talking about? … remember, you’re blasting down a snow-covered runway, with the windshield wipers on – unable to see very far ahead … do you care what progress you’re making? … do you care what your airspeed is now? By the time you ask yourself those questions, he again says “Ah … that’s not right” All this while you’ve heard the tower controller issuing landing clearance to that guy behind you … You look at the airspeed … 80 knots … and you decide to let the F/O know where you were and your airspeed … so you say in a calm and clear voice, “Yes it is, there’s eighty” … and just as you get those words from your mouth, you hear the landing traffic over the tower frequency respond to the tower controller’s clearance by saying, “1451 cleared to land over the lights.” WHAT?!?!? OVER THE FRIGGIN LIGHTS!?!?!? What do you do, now … abort?

It would seem that Mr. Clandestino is “hoisted by his own petard.” By way of example he states:

“…people are convinced of something because they want to be convinced. If reading the accident report pages where crew's mistakes are neatly explained fills you with horror and, despite the facts, you want to believe that QH90 (or any other) crew did their best but it was tragically insufficient, to sooth your anxiety you would do well to listen to alternative theories of e.g: de-icing with water…”
Or … perhaps this could be said somewhat differently … “people are convinced of something because they want to be convinced. If reading the accident report pages where crew's mistakes are neatly explained fills you with satisfaction and comfort because you never make those kinds of errors, and, because of these facts, you want to believe that you are insulated from similar potentialities of crew error or confluence of other apparently dissimilar circumstances such that your anxiety may be soothed, you would do well to read only the report and not challenge any aspect regardless of how familiar that aspect may sound.”

Again, a worthwhile quote:
Whatever suits you, terms of the PPRuNe use do not preclude going whichever path you choose. Outcomes might differ, though.

One additional quote from the Accident Report - once again leading interested readers to the conclusion that the airplane was "auto-rotated" to an unrealisitc and unrecoverable pitch attidue due to the wing contamination caused by impropter deicing/anti-icing procedures and equipment.
Ground witnesses generally agreed that the aircraft was flying at an unusually low altitude with the wings level and had attained a nose-high attitude of 30 degrees to 40 degrees nose up before it hit the bridge.
A slight tendency to pitch up - slight tendency - 30 to 40 degrees nose up? Really?

[Clandestino]

I cannot refrain from intervening because it can be deadly for your seeds to sprout.

Don't worry, chances are they won't. Pilots who know a bit about aerodynamics can have good laugh at some propositions aired here. Those who don't, probably won't look up to PPRuNe to expand their knowledge. Those who are ignorant of matters aeronautical, yet easily influenced into accepting as true the lethally wrong theory, when appeal to their emotions is made, are very unlikely to have any chance of putting the wrong theory into practice. Main reason being the lack of piece of paper, unequivocally showing that relevant authority deems them capable of safely slipping the surly bonds of earth.

The fellow plays his own tune for his own audience.

No need too feed him.

[sabenaboy]

Well, great post once again. You convinced me -and many others, Im sure- even more!
But... I still think you should have followed my advice and stop responding.

He said it himself: "No need to feed him" (He's not worth the trouble and he's just harassing you. Don't take the bite.)


(English is not my mother tongue. I apologise for not being able to respond as eloquently as you can.)

[Clandestino]

Got away with the snowy wings - again!

Interestingly, when you open the video on YouTube, first suggested similar video is:

Последний Заход - Крушение рейса 90

It's about AirFlorida 90. Recommended if your Russian is better than English.

[Basil]

rainbow100,
Interesting, but would not alter my operation one bit.
That snow should have been removed.

Only exception to my mind would have been overriding military requirement.

[de facto]

Maybe its time the FAA updates its FARs?
According to FAR 121 ,Aeroflot did not break any of its rules..as reckless as its pilots actions may have been..

(d) A certificate holder may continue to operate under this section without a program as required in paragraph (c) of this section, if it includes in its operations specifications a requirement that, any time conditions are such that frost, ice, or snow may reasonably be expected to adhere to the aircraft, no aircraft will take off unless it has been checked to ensure that the wings, control surfaces, and other critical surfaces are free of frost, ice, and snow. The check must occur within five minutes prior to beginning takeoff. This check must be accomplished from outside the aircraft.

[Doc. No. 6258, 29 FR 19222, Dec. 31, 1964, as amended by Amdt. 121–231, 57 FR 44942, Sept. 29, 1992; Amdt. 121–253, 61 FR 2615, Jan. 26, 1996]

[Mad (Flt) Scientist]

@de facto

How on earth do you conclude that aircraft could possibly have complied with:

it has been checked to ensure that the wings, control surfaces, and other critical surfaces are free of frost, ice, and snow.

Never mind that conducting an inspection from outside the aircraft within 5 mins of takeoff at a Russian airport is probably impossible without the security guys getting very excited.

[caber]

Maybe its time the FAA updates its FARs?
According to FAR 121 ,Aeroflot did not break any of its rules..as reckless as its pilots actions may have been..


I don't think the reg you quoted means what you think it means. All that says is IF a part 121 operator does not have an approved ground deicing/anti-icing program, they may still take off when weather conditions could create structural contamination on the aircraft if they do a pre-takeoff contamination check within 5 minutes of takeoff from the exterior of the aircraft. If there is no ice or snow adhering, they may take off.

If the airline does have an approved ground deicing/anti-icing program, then that program must be adhered to.

Basically, if I had a little commuter operation out of San Juan, it might not be worth it to me to come up with a ground ice program in my ops specs. If a freak snowstorm hit the Caribbean, I could still take off if I was able to perform the pre-takeoff contamination check AND the airplane was clean. If anything was adhering to the wings, or any other critical surface, no takeoff.

With that in mind, from that video the Aeroflot plane would have been in violation.

[boguing]

Taking what FAR 121 actually says:-

"(d) A certificate holder may continue to operate under this section without a program as required in paragraph (c) of this section, if it includes in its operations specifications a requirement that, any time conditions are such that frost, ice, or snow may reasonably be expected to adhere to the aircraft, no aircraft will take off unless..."

Then if conditions are such that frost, ice, or snow may reasonably expected NOT to adhere.. then it does NOT apply.

So in properly cold countries, some of which have an almost infinite number of words for different types of snow, it is possible that a pilot with that knowledge might know that it was dry snow and not thick enough for the weight to cause melting on a very cold wing/tail. And that a couple of sweeps with a soft broom confirmed that he was correct.

I live in balmy Surrey and even I can tell which snow I need to clear from my bonnet, and that which I know will have blown off by the end of the lane.

I'm not saying that I wouldn't have been raising hell in the cabin on that flight, but that FAR 121 does offer a get out clause.

[lomapaseo]

Boguing


Taking what FAR 121 actually says:-

"(d) A certificate holder may continue to operate under this section without a program as required in paragraph (c) of this section, if it includes in its operations specifications a requirement that, any time conditions are such that frost, ice, or snow may reasonably be expected to adhere to the aircraft, no aircraft will take off unless..."



Then if conditions are such that frost, ice, or snow may reasonably expected NOT to adhere.. then it does NOT apply.



That is a very misleading quote since it leaves out the conditional statements after the word "unless"

That regulation is what it is, and not subject to personal intertpretations by exclusions and/or additions.

[boguing]

Lompaseo, you are one of the last people that I would dare to open a debate with - for fear of losing tragically!

I'm really not trying to let this crew off the hook.

But the 'unless' is irrelevant if the earlier test (reasonably expected..) is not met.

I don't even know whether FAR 121 was relevant to this flight.

Your first quote of my quote - if you follow?! Was lifted from preceding posts, so if it was wrong, mea culpa.

The second quote you used was all my own words.

And I stand by it. If you reasonably expect the snow to fall off without any help other than airspeed, then I read that you are 'good to go'.

[ImbracableCrunk]

If you reasonably expect the snow to fall off without any help other than airspeed, then I read that you are 'good to go'.

I think reasonably is stronger than "a hunch." An inspection with a wand reveals nothing adhering, then you can reasonably expect. Not wanting to de-ice because you've got a waiting devushka u vodka at your kvartirye, is a reason, but not reasonable.

[boguing]

I don't know how much more clearly I can say that if I were there I would have been terrified.

But there are many people who could determine what is and is not dry snow. If that happened to be a teetotal Russian, I would not bet against him/her.

I'm just pointing out that local knowledge is valuable, and the test of 'reasonable' might hang upon that.

So many laws are open to driving the proverbial coach and horses through. This seems to be one of them.

[UUUWZDZX]

Apologize for leaving you all without new developments on this story.

Having received that reply from aeroflot (snow was blown off, no violations, etc) in the beginning of April, I was looking to receive another statement, as I sent them a brief outline of regulatory provisions which were apparently violated. Since there was no reply and it seemed that the story was about to get lost amongst others, I launched a dedicated website, link (http://snowAFL.ru) (it's all in russian) on the 1'st of May. Narrative is about 5000 words: facts of the case (differentiation between 'wet' and 'dry' snow, speculation about possible presence of ice, etc), violations (quotations from AFL's SOP, FCOM, Russian Air Law), outline of effect of wing contamination on aerodynamics (basic theory, quotations from Airbus, ICAO, NTSB, FAA, statistics on a number of fatal accidents caused by contamination on takeoff).

This website has caused quite a tornado in russian internet, and is now widely quoted on different websites (unfortunately not much media interest though). Finally russian aviation community woke up to the fact. Generally public (aviation-affiliated) condemns actions of aeroflot personnel and of their top managers who made the statement. Almost all airlines in russia and in CIS are now aware of this case. Aeroflot guys visit the website at least 5 times a day from their offices (IP-tracking). According to my sources, there is a sence of moderate panic among managers of aeroflot, and particulary among two individuals who made the statement (Mr. Chalik and Coldunov). This case is also widely discussed among aeroflot pilots.

I sent letters to EASA, SkyTeam, Airbus, IATA and Bermuda CAA. IATA indeed got interested and contacted russian CAA with fury (apparently) about the incident and aeroflot's reply. There was also a SAE conference on Aircraft De-Icing in Prague in the beginning of May, two of the people I know visited it and they reported loads of tea-room discussions condemning aeroflot's actions as well. Also, as you probably know, most russian airliners are registered in off-shore states, such as Bermuda. I sent them a quick letter and got the following reply (7'th of May):

http://snowafl.ru/graphics/VP-BKY_BERMUDA_CAA_REPLY.jpg


Bermuda initiated talks and does take it seriously, how about russian CAA? Keep on reading...


Here starts the interesting part

A few days ago I wrote a public petition, signed by 80+ people, addressed to aeroflot and demanding apologies for gross misconduct of relevant regulations concerning removal of contaminants prior to takeoff.

Yesterday (on 14'th of May) I made a call to russian CAA (just out of curiosity), to the head of safety inspections department. To my total amazement his exact words (amongst other bluff) were: there were no violations of FCOM/SOP/Russian Air Law (1), snow was dry (2), there was no danger to people on board (3). I tried my best to almost quote excerpts from FCOM and SOP, but he delicately attempted to avoid my direct questions. Since I was not recording this call, I decided not to interrogate him further. So there is no case to answer, no one was punished, incident almost got lost quietly [almost, but not anymore :) ].

At the moment i'm preparing another petition, to russian CAA. By russian law, as a state department, they must respond to any inbound queries. So that will be an interesting reply to read. I very much doubt they will dare to confirm that there was no direct violation of FCOM/SOP or that the snow was dry indeed.

PS. For those of you who don't know, as per russian air law, it is not permitted to takeoff with wet snow (amongst other contaminats), unless otherwise stated in FCOM. Aeroflot A320 FCOM and SOP is a standard Airbus-recommended text, so it prohibits to takeoff with any contamination on the upper surface of the wing.

Anyway, their argument will be very weak, if they produce it and don't change their mind. Snow shown on the video demonstrates qualities of a wet snow, so that's a violation of russian air law (1), FCOM cleary prohibits to takeoff with any contamination - another violation (2).

Once we get a reply from CAA, if they still argue that there were no violations, we'd probably forward the whole case to transport judiciary for their own independent inquiry.

BTW, Russian CAA is very well known to 'cooperate' with aeroflot. For instance recently they lost a case in court to other russian carrier for not allowing them to compete with aeroflot on certain routes, where aeroflot operated solely alone and held a monopolistic share.

PS. I also received accounts from pilots of aeroflot who reported captain of that flight to be totally arrogant, impulsive and cowboy-like. On one occasion, he called a group of queuing junior second officers in front of medical room 'shut up puppys and let me go' and skipped the queue. On the way out when they questioned him, reply was 'you'r too junior, or wanna speak?'. I'm also in contact with other AFL pilot who reporting him being arrogant on a flight deck [will post more details once I got them].

PS2. Please don't quote FAR requirements in this topic about 'adhering', it's irrelevant. Under russian air law, the key word is 'wet snow' (presence of).

PS3. Here is the video of another aeroflot takeoff, difference being - it is a dry snow - kind of thing which is allowed as per russian air law, but not as per FCOM - http://www.youtube.com/watch?v=92bcNoOm4pk



PS4. To those guys who fly to russia - you are welcome to takeoff with snow -- as per russian CAA :)

[aerobat77]

Once we get a reply from CAA, if they still argue that there were no violations, we'd probably forward the whole case to transport judiciary for their own independent inquiry.hey ! do not expect to get another reply since they will not mess up with a major russian carrier to satisfy some heated internet discussions for a thing where finally nothing happened.

law prohibits a take off with snow on wings, not the take off run. drag calculations are given for operations in contaminated enviroments- and additional drag is also given with a deicing slush on the wings before it sheers off.

deicing alone is not the magic word for safe winter operation, it depends on many factors and real life serves you more questions than any fcom wil give you answers.

on the other hand...

the more interesting think you stated here is the arrogance and cowboy style of the captain. if he really is thatlike he should be eliminated not because of any snow , but because of intentionally operating close to the edge , with passengers on board.

there are far more situations than snow that blows off not instantly but short before rotation where a cowboy may run out of luck- in summer or winter !

UUUW: may we ask why you use up such resources to nail down this captain ? something personal?

cheers !

[lomapaseo]

UUUWZDZX

Seems to me that the problem is not the Captain's personality. judgement etc. but an edenmic shortfall in their CAA for promoting and fostering a unique difference in interpretations of the regulations in the world wide community.

For this corrective action one must start at the top of the chain and the pilots will follow.

I feel that too much criticism is being directed against the last guy in the chain (the captain). If continued nothing will be improved for the benefit of the flying public

in english slang, thowing the guy under the bus

[UUUWZDZX]

UUUW: may we ask why you use up such resources to nail down this captain ? something personal?


I don't consider this as a significant campaign... No, I don't know this person.

[UUUWZDZX]

It seems every time I post smth in this topic, it's outrageous :)

Been browsing AFL A320 SOP and found very familiar Boeing words, opened Boeing QRH and was lost for words...: SOP of Aeroflot for A319-320-321 (approved by CAA) includes upset recovery procedure - COMPLETELY copied (and translated) from B767 QRH. There is NO mention of FBW at all: bank angle, high AOA & pitch attitude protection, abnormal attitude law, etc..

On the left - AFL A319/320/321 SOP, on the right QRH of B767-300ER:

It's all copied word-to-word, even punctuation.

https://p.twimg.com/As9mZcFCMAAmCwG.jpg:large




You might say it's an error (copied erroneously). Unfortunately it is not. Look at the next page. They copied actual procedure as well, BUT changed 'elevator' to 'side stick'. WTF??

http://snowafl.ru/NHR.jpg

https://p.twimg.com/As9q_7YCMAAoiaM.jpg:large






It might be partly applicable to any conventional aircraft, but how about FBW logic?

Bank Angle Protection:


Bank angle protection prevents that any major upset, or PF mishandling, causes the aircraft to be in a high-bank situation (wherein aircraft recovery is complex, due to the difficulty to properly assess such a situation and readily react). Bank angle protection provides the PF with full authority
to efficiently achieve any required roll maneuver.

The maximum achievable bank angle is plus or minus:
• 67 °, within the Normal Flight envelope (2.5 g level flight)
• 40 °, in high Speed protection (to prevent spiral dive)
• 45 °, in high Angle-Of-Attack protection



High Pitch Attitude Protection:


Excessive pitch attitudes, caused by upsets or inappropriate maneuvers, lead to hazardous situations:

• Too high a nose-up ▸ Very rapid energy loss
• Too low a nose-down ▸ Very rapid energy gain

Furthermore, there is no emergency situation that requires flying at excessive attitudes. For these reasons, pitch attitude protection limits pitch attitude to plus 30 °/minus 15 °.

Pitch attitude protection enhances high speed protection, high load factor protection, and high AOA protection.



Abnormal Attitude Law:



If the aircraft is, for any reason, far outside the normal flight envelope and reaches an abnormal attitude, the normal controls are modified and provide the PF with maximum efficiency in regaining normal attitudes. (An example of a typical reason for being far outside the normal flight envelope
would be the avoidance of a mid-air collision).

The so-called "abnormal attitude" law is :
• Pitch alternate with load factor protection (without autotrim)
• Lateral direct law with yaw alternate

These laws trigger, when extreme values are reached:

• Pitch (50 ° up, 30 ° down)
• Bank (125 °)
• AOA (30 °, -10 °)
• Speed (440 kt, 60 kt)
• Mach (0.96, 0.1).

It is very unlikely that the aircraft will reach these attitudes, because fly-by-wire provides protection to ensure rapid reaction far in advance. This will minimize the effect and potential for such aerodynamic upsets.

The effectiveness of fly-by-wire architecture, and the existence of control laws, eliminate the need for upset recovery maneuvers to be trained on protected Airbus aircraft.


This would leave AFL crews "fighting" with FBW (especially those, who poorly know FCTM). Why posting such critical information in SOP without reference to aircraft systems, their capabilities and limitations? Also, why include references to the use of stabilizer trim without out any additional details -- in auto (under normal law) or manual mode?

[cwatters]

Sorry if silly question but..Does the A320 side stick have a stick shaker or did they change that bit when they did the translation?

I did look in the A320 Flight Crew Training Manual but can't see a reference suggesting the A320 has a stick shaker. The word shaker occurs just once in the section dealing with protections and that's to do with the A320 protections making it easier to fly at stick shaker AOA.

[J.O.]

There is no stick shaker in the Airbus FBW aircraft. There are aural warnings, such as "SPEED-SPEED -SPEED" or "STALL" when speed / energy targets are reached, but in normal comtrol laws,you can hold the sidestick at full back and the aircraft will fly at the lowest speed and it will adjust pitch / thrust accordingly to maintain it.

[up_down_n_out]

"Been browsing AFL A320 SOP and found very familiar Boeing words, opened Boeing QRH and was lost for words...:"

And you are suprised?

Fake Diplomas = Fake Modernization (http://www.themoscowtimes.com/opinion/article/fake-diplomas--fake-modernization/414673.html)

Take two (http://www.washingtontimes.com/news/2006/mar/24/20060324-104106-9971r/?page=all) example (http://www.rferl.org/content/article/1067113.html)s of a recently "relected" president who never left.

You are evidently just touching the tip of an enormous iceberg in a country where something like 50% of law degrees are fake, engineers work at Sukhoi with fake qualifications (http://www.themoscowtimes.com/opinion/article/fake-diplomas--fake-modernization/414673.html) and fake companies (http://www.nybooks.com/articles/archives/2012/apr/26/vladimirs-tale/?pagination=false) are used to launder stolen companies (http://lawandorderinrussia.org/).

...that is exactly the point about contemporary Russia: there is no proof of anything that happened.
Documents are missing.
People have disappeared or changed their identities.

Major companies are owned by nonexistent shell companies, and they mysteriously do the president’s bidding...

Have you been asleep for a decade?

Wake up smell the coffee! :D

[The SSK]

Presumably an unconnected development ...

Russia may blacklist air passengers, pilots - NY Daily News (http://india.nydailynews.com/business/048f3e9175189572f239c9c46943cb95/russia-may-blacklist-air-passengers-pilots)

[up_down_n_out]

And the person behind that move in the Duma, is none other than .....the...

Vitaly Saveliev, chief executive officer of Russian flag carrier Aeroflot, who cut his teeth on .....?

"...when the Sayano-Shushenskaya HEPP (http://en.wikipedia.org/wiki/2009_Sayano-Shushenskaya_hydro_accident) was completed, Vitaly Saveliev returned to Leningrad"..
..the same HEPP that was one of the greatest post war industrial disasters after the 1986 Chernobyl accident.


...a particularly well placed and appropriate personality it should be said for legifering into the pilot recruitment & safety of companies other than Aeroflot and protecting AFL's monopolies.


Just in case you see no connection in the obsessive "safety regime" in Russia watch this.


A catastrophe that was completely avoidable like so many others.

[typhoid]

My understanding is that both Boeing and Airbus worked together to produce upset recovery procedures that are standard across the industry.

That is why they are the same.

[9.G]

a case to study not only contaminated wings takeoff performance but a egocentric personalities as such. :ok:

[lomapaseo]

a case to study not only contaminated wings takeoff performance but a egocentric personalities as such

Just where is the evidence of such:confused:

in the cockpit

in the airlne management ?

in the CAA ?

Until the facts are in, assigning personal traits specifically is out of place

[9.G]

Just where is the evidence of such Evidence on a rumor network, that's the best joke I've ever heard. You've made my day amigo therefore you deserve another hint. Empty vessels makes the most noise. Go figure. :}

[de facto]

@de facto

How on earth do you conclude that aircraft could possibly have complied with:

Quote:
it has been checked to ensure that the wings, control surfaces, and other critical surfaces are free of frost, ice, and snow.
Never mind that conducting an inspection from outside the aircraft within 5 mins of takeoff at a Russian airport is probably impossible without the security guys getting very excited.

The FAR 121 is stating "(d) A certificate holder may continue to operate under this section without a program as required in paragraph (c) of this section, if it includes in its operations specifications a requirement that, any time conditions are such that frost, ice, or snow may reasonably be expected to adhere to the aircraft, no aircraft will take off unless..."

The 'MAY BE REASONABLY be expected to adhere...' is leaving a lot on the unreasonable PICs out there...therefore maybe time for a review more strict FAR.

FAA is all about Would/should/could.....maybe its time it uses SHALL NOT more often.....

[RatherBeFlying]

Some years ago, I got SLFed through ORD while a low was dumping considerable quantities of lake effect wet snow over everything. We got deiced with what must have been type IV at the gate and then joined the conga line to departure. It took more than 5 minutes while considerable snow accumulated on the wing which I could see quite well. The several a/c ahead of us were not turning into fireballs on takeoff; so, I decided that the deicers knew their job and did not put up a fuss.

At about 50 kt, the blanket of snow sheared off in what looked like a single piece and the takeoff proceeded normally. I don't think ORD was removing the dumped snow after each takeoff, but I would not be surprised that clearing operations were in progress on the next runway to come in use.

UUUWZDZX has posted a video showing how easily dry snow comes off -- quite a bit quicker and more cleanly than the wetter stuff at M01 in the first video. Snow close to 0C worries me more than snow at -10C on both a/c and roads, but we also have to take account of surface temperature.

The videos show that there's different degrees of adhesion. If the adhesion is good past Vr, it's definitely too much. In the first video, the adhesion got pretty close to Vr and in some locations exceeded Vr. Not much margin there.

[Basil]

RBF,
At about 50 kt, the blanket of snow sheared off
May we know the name of the airine?

[Teddy Robinson]

as a cautionary note .. occasionally the de-icers get it wrong.
I refer you to the BA46 incident at CDG circa 2005, when the aircraft was mistakenly de-iced with 100% water.
An aircraft following it in line for departure noticed large icicles forming on the tail and informed ATC.
Aircraft returned to stand.

[RatherBeFlying]

RBF,
Quote: At about 50 kt, the blanket of snow sheared off

May we know the name of the airine?

That was some ten years ago. It was a major US carrier, perhaps United. It's competitors were ahead and behind with similar snow accumulations.

[Basil]

It was a major US carrier, perhaps United. It's competitors were ahead and behind with similar snow accumulations.
Thank you.
That's a worry.

[BTDTB4]

The 'MAY BE REASONABLY be expected to adhere...' is leaving a lot on the unreasonable PICs out there...therefore maybe time for a review more strict FAR.
FAA is all about Would/should/could.....maybe its time it uses SHALL NOT more often.....

Unfortunately, it would appear that this particular regulator is intent on using rather ambiguous terms out of fear of generating unintended consequences with more specifically worded regulations. When there is a misunderstanding … or there is reason to provide more specific justification for what has been included in the rules, this particular regulator likes relying on Advisory Circulars, Notices, Bulletins, etc. to effectively accomplish what they fear would be something that they had not intended – primarily because they have a process that takes decades to effectively overhaul an existing regulation. This reminds me of the race car driver who loses control of his race car but continues in the race by bouncing off the walls and other cars in the race … and he continues because he believes no one can condemn him for “giving up” and leaving the race … no one can condemn him for not wanting to win the race … and no one can condemn him for forgetting to put a friggin steering wheel in his race car … because they will never know – unless he stops!

[lomapaseo]

Unfortunately, it would appear that this particular regulator is intent on using rather ambiguous terms out of fear of generating unintended consequences with more specifically worded regulations

One does not write the rules for idiots

That's the job of the state's governing process to write laws not rules.

[jurassicjockey]

At about 50 kt, the blanket of snow sheared off in what looked like a single piece and the takeoff proceeded normally.

Not going to get into the discussion of Type IV fluid failure, but you should be aware that Type IV fluid is a non-Newtonian fluid, meaning that the viscosity decreases as shear stress is applied. What that means on an aircraft is that as the speed gets up to around 80kts, the layer of fluid will slide off the wing, taking any contamination with it.

[aerobat77]

FAA is all about Would/should/could.....maybe its time it uses SHALL NOT more often.....

muuah. i think the FAA , CAA or the german LBA are rigid enough !

the regulations are in my opinion here perfectly written and match real life, you will find many more regulations tah are more stupid .

[Ice-bore]

What that means on an aircraft is that as the speed gets up to around 80kts, the layer of fluid will slide off the wing, taking any contamination with it.

jurassicjockey, the information you are providing here is incorrect. The fluid will have failed at this stage and a further de-icing/anti-icing treatment will be required. Please see posts 331 and 339 for further information.

[UUUWZDZX]

Brief update on the story:

1. My friend and I asked a member of Russian Parliament to prepare an inquiry into this case, since it seems that russian CAA allied with aeroflot and denies any violations. Shortly he will be sending demands to explain reasons for denial of Russian air law by aeroflot and russian CAA.

2. The guy who was behind the statement (flight director of Aeroflot, Mr. Chalik) was visiting a TV show just 4 days before making that statement. Show was about UTAIR ATR72 crash, specifically about de/anti-icing procedures (take off with contaminated wings is being viewed as the most probable cause at this time). In his speech he mentioned ICAO doc 9640 (and hence clean aircraft concept) and that aircraft must be clean before PIC arrives (implying ground staff must perform de-icing => not acceptable to takeoff assuming contamination will be blown away).

Clearly 4 days later he turned a blind eye in relation to identical case, but on Aeroflot flight -- 'there were no violations, snow was blown away during takeoff roll'. Ignored doc 9640 and all the rest he said 96 hours earlier. What a short memory or may be reluctance to admit wrong doing by one of his own pilots? :)

[jurassicjockey]

jurassicjockey, the information you are providing here is incorrect. The fluid will have failed at this stage and a further de-icing/anti-icing treatment will be required. Please see posts 331 and 339 for further information."

Not incorrect. I did predicate my post with the disclaimer that I wasn't going to discuss fluid failure. By the description of the scenario, the type IV had failed, however, I wasn't there to judge it. Perhaps I shouldn't have used the word contamination, as that might have thrown you off. However, prior to failure, in a snowfall scenario, the fluid does absorb contamination. That is what it is designed to do. Prior to fluid failure, the contamination will not prevent the fluid from performing properly. That performance involves shearing off, and taking any contamination that it had absorbed with it.

[UUUWZDZX]

OUTCOME OF THE STORY. After receiving public petition I mentioned earlier, Russian CAA finally acted upon this incident. They ordered Aeroflot to conduct investigation. Aeroflot swiftly assembled committee and on 28'th of May concluded:

1. There was indeed a violation of Aeroflot SOP (crew and ground personnel made a wrong decision not to conduct de/anti-icing of aircraft after overnight stay with snow precipitation)

2. Amendments were made to Aeroflot SOP regarding de/anti-icing procedures.

3. Captain of the flight was demoted to First Officer.

4. Other personnel received various disciplinary sanctions.


That's 6 months after actual incident and 2 months after initial reaction of Aeroflot and Russian SOP that there was no violations :)

More info (in Russian) on link (http://snowAFL.ru)

[vordmeafl]

Captain of that flight has transfered to FO position. 01.06.12

[mercurydancer]

That is very reassuring to hear. Aeroflot do have to maintain its image as a reliable airline, as do any airlines for that matter. It is good to see something positive come out of this. Maybe Aeroflot captains wont be so cavalier next time.

[de facto]

Very good news indeed.

[LukeSi]

Glad to hear that action has been taken. As has been said, hopefully it will show that taking risks like that does not go unpunished.

[fox niner]

And now, science has come up with a solution:

New spin on antifreeze: Researchers create ultra slippery anti-ice and anti-frost surfaces (http://www.sciencedaily.com/releases/2012/06/120611134350.htm)

No more de-icing required. EVER. in the near future?