Take off with snow on wing

[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]

Originally Posted by Doves

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.

Originally Posted by Doves

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?

Originally Posted by Doves

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.

Originally Posted by Doves

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.

Originally Posted by Doves

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.

Originally Posted by Doves

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.

Originally Posted by Doves

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.

Originally Posted by Doves

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.

Originally Posted by Doves

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.”

Originally Posted by Doves

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 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, 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.

[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 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]

Originally Posted by Doves

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]

to AirRabbit

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

Code:

Nevertheless you will agree with me that the following illegalities were committed:

Code:

 - 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.

Code:

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.

Code:

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.”

Code:

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, ….

Code:

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?)

Code:

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.”

Code:

They had found that the acceleration was so poor that they had reached 120 knots after 45 seconds.

From 1559:46 to 1600:21

Code:

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]

Originally Posted by rabski

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]

to AirRabbit

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...

Originally Posted by Boeing Airplane Flight Manual, B-737

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...

Originally Posted by Accident Report, page 137

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.

Originally Posted by Doves

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.

Originally Posted by Doves

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.

Originally Posted by Doves

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.

Originally Posted by Doves

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.

Originally Posted by rabski

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.