Lonewolf_50

For the love of all that is Guinness, let's not recreate the 10 threads of AF447 here ...

DozyWannabe

Amen. (That's why I was trying to keep it brief! As well as recommending referring to the existing threads.)

BARKINGMAD

Dozy, is this a new EASA/JAA/ICAO Ops limit which has escaped my attention to date?

If possible please supply chapter and verse so's I can avoid the specified conditions when they occur or are forecast.

DozyWannabe

@BARKINGMAD - I was thinking of AA1420.

Capn Bloggs

Not "couldn't", "didn't". Poor design.

BOAC did put 'on the ground' in quotes, the inference which is obvious.

DozyWannabe

How so? Can you name and show a design which works consistently and in all scenarios when that far outside of the envelope? Bet you can't.

Again, how so? As far as the systems are concerned an IAS of <60kts does not mean the same as "on the ground".

Capn Bloggs

I don't need to, Dozy, nor did I ever say there was one. Some bright spark thought that aeroplanes couldn't fly below 60KIAS so decided that they'd turn the stall warning off below that. Bad decision. If the aeroplane's in the air and below stall speed/above stall AoA, keep the stall warning on! Why is that concept so hard for you to grasp?

It's obvious what BOAC meant.

DozyWannabe

We went over this several times on the Tech Log threads - the designers did not intend to inhibit the Stall Warning below 60kts IAS, the Stall Warning was silenced because the AoA data was not valid below that IAS. I'd be prepared to wager any amount you'd care to name that this is true for most, if not all, modern types. As was discussed on the Tech Log threads, latching Stall Warning on would work in this scenario, but would not work in a scenario where the <60kts IAS value was false.

Would you care to enlighten me? In all seriousness, I'm here to learn.

aerobat77

well, to recover would be the next step , but when i understand it right they all did not even realized they are in a stall.

its not a forum,s job to blame the crew but we have to remember , all this happened out of a level flight with a constant Speed and altitude - with a stabilized and properly trimmed aircraft.

so of course doing nothing beyond maintaining altitude and wings level would be much smarter then just giving a full pull on the yoke and so forcing to stall. the question why he did this will never be answered i guess.

further its confusing not to realize it for several minutes by three people - when you have 20 deg pitch up but go down like a rock - what could it be other than a stalled condition ?

some might think that any ppl holder would have realized and managed it better and so Coroners start to blame the skills.

i have to give a point that in this very particular Situation - blocked tubes, stall inhibit below 60 kts - the design of the System might have further confused the crew, but this Situation is so dramatically out of any flight envelope of this aircraft and you have to make such fundamental piloting errors to force an airliner into this situation that not even Airbus thought of it designing the stall warning system.

best regards

AlphaZuluRomeo

Let's review some points.

The stall warning is suppressed below 60 kts IAS because below that value, the AoA reading are deemed unreliable. The fact that this also avoids false alarm when on the ground is incidental, not (prime) causal.

The F/Os (both) were confused before that point. They didn't react to the Stall Warning. I agree that the S/W suppression would only have added more confusion (and perhaps prevented the CPT of making his mind on what really was ongoing when he came back to the F/D) but the crew mistrusted instruments early, i.e. before that S/W suppression. Maybe, maybe, if the S/W had not been suppressed, the outcome would have been better. But that's only a guess, seeing how the S/W was previously ignored.

To be precise, it was not exactly true. The sensed IAS was below 60 kts. The real IAS was somewhere above 100 kts (as calculated later), but the extreme AoA prevented the fixed-axis pitot probes to catch all the dynamic pressure. Sad.

This is possible indeed. Was not voiced as such, so we don't know. And would imply that "STALL STALL" was not recognized as what it means, so it's sadly not better for the crew.

Lonewolf_50

There is nothing unnatural about dying when one's body is subjected to dynamic impact with the ocean's surface as a result of falling roughly 10,000 fpm.

What would be both unusual and unnatural (maybe a robot?) would be surviving same impact.

BOAC

- really? What an interesting life you must lead.

alf5071h

“You can only conclude that they were unsufficiently trained to recover from a stall.”

Not at all, the conclusion is made with hindsight which infers that because an aircraft stalled – was not recovered, crew training was a cause.

A better inference from the data could be that the crew did not fly the aircraft as expected immediately after the failure. This assumes that the ‘expectation’ was that any crew could fly without airspeed, in the prevailing conditions and with all of the consequential system aspects of the initial failure. In support of this was the recent crew training for flight without airspeed.
The accident data might be better interpreted as the crew following the procedure for loss of airspeed after take-off / climb, a memory item which perhaps was better practiced / stressed in teaching (and better recalled in stressed conditions) instead of the level flight case.
The stall resulted from this misapplication. Furthermore the stalled condition was such that few if any crews would have been trained for; full nose-up trim, conflicting alerts and warnings, at night, and near convective weather.
With due respect to the coroner, there did not appear to be any evidence linking public concern, automation dependency, and the adequacy of training.

This and other discussions might similarly falsely conclude that that modern aircraft and automation ‘cause’ accidents due to the reduction in manual flying, yet completely overlook the everyday successes, presumably with some manual flight, and the very low accident rate. Yes the industry can do better, but not by focussing on one aspect.

The UK coroner stated that – ‘The pilots were not adequately trained to handle the aircraft safely in the particular high-altitude emergency situation that night’. There is no inference as to whether the training given was matched to the situation and the prevailing human factors; there appeared to be a systematic weakness. However, with the usual inability to identify the effect of each contribution – regulator, manufacturer, operator, crew, individual, it might be difficult to allocate ‘blame’ which the legal systems prefer, as opposed to understanding the contributors and alleviation sought by aviation.

Lonewolf_50

BOAC, you may wish to look up the term "play on words" ...

172510

The question of training is to my opinion the key one.
Is it possible to train a crew so that in case of another failure of the same equipment in the same weather conditions etc. the aircrew would not crash?
If the answer is yes, then the training of the crashed aircraft crew was not adequate.
If the answer is no, or if the answer is that it's not reasonably doable to train crews to get out of any kind of failure that might happen, then either you accept that public air transportation safety cannot be improved, or you do something.

Amongst the things that might be done, maybe
-initial training of pilots (verbal reasoning etc.) , the EASA ATPL written exam does not require any sort of reasoning ability.
-dialog between the computer and the crew, for instance, if the angle of attack values are discrepant from one sensor to another, show the raw data to the crew instead of letting the computer decide on his own that the bad ones are good without telling the crew; (cf canet plage accident), if a stall is reported by the computer, show the raw data used by the computer to draw that conclusion (angle of attack values, etc.).

IcePack

On the CVR a couple of comments intrigued me.
1) we have no vertical speed & later
2) we have no indications.

Um inadequate training on no instrumentation flight. Maybe, but who knows why 2 reasonable flight time pilots thought 16 deg NU at 35000 was ok. We will never know.
But whatever definitely a lack of training coroner probably got it right.

Flyingmole

Anyone who wants a more informed view on this aspect of it should just go to and listen to David Learmount's very persuasive case. His view is that it is not - as he puts it - a loss of flying skills but a loss of situation awareness and cognition.

DozyWannabe

Except we know that the LHS instrumentation (at least) was OK, because it was recorded on the DFDR.

Learmount's summary is substantively correct in most senses, but what he does not acknowledge is that during the initial events of the sequence, the PNF tries to draw attention several times to the PF that he thinks the aircraft is being mishandled. Unfortunately, for whatever reason, the PNF elects to defer the decision to begin corrective action until the Captain has been summoned to the flight deck.

jimjim1

@dozy

No.

The PNF made his best effort to persuade the PF to put the nose down.

However:-

From memory, meaning I have not re-read the reports recently, I think that there was one crucial moment that set the scene for the crash.

As the Captain left the flight deck he kind of casually inferred that the less experienced pilot (who happened to be in the LH Seat) was "acting Captain".

As it happened the LHS pilot declined to accept the (very good) advice coming from a less (perhaps inadequately) assertive but far more experienced pilot who's role was Pilot Monitoring. Quite simply I suspect that his (the pilot flying's) head was too big for his boots.

I think that this was the Captains crucial error. (Well apart from leaving the flight deck at all given the proximity of the Inter Tropical Convergence Zone and the associated radar visible thunderstorms, which were a mere 10 minutes ahead).

I feel quite strongly that if the Captain had not given the "acting captain" nod to the inexperienced PF that the crash would very likely not have occurred.

bubbers44

But why have pilots in airplanes designated as PIC somebody that does not know how to fly? He did a stupid maneuver pitching up between the two of them to an impossible attitude to a full stall. No pilot I have ever met would ever do that because they know how to fly.

I know, it is the new generation of pilots so get used to it. I think I will take the train.