Take off with snow on wing

[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]

Originally Posted by AirRabbit

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? 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.

[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]

just my two ruble worth..

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]

@Jetaim

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]

Originally Posted by Checkboard

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]

I believe you're right

@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!

[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.