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

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

"attempting a landing in a thunderstorm that exceeds minima"
 

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. :)

@BARKINGMAD - I was thinking of AA1420.

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

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

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".

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.

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.

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

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.

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. :p

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

- really? What an interesting life you must lead.

“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.

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

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.).

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.

Loss of situation awareness & cognition
 

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.

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.

@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.

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.

"casually inferred" ? what on earth does that mean ?

He probably didn't know how incompetent the pilot in the left seat was. With an equally incompetent pilot in the right seat pulling up into a full stall it was all over. Hopefully we haven't reached this state in the US. We are getting close with the pilot mills qualifying pilots who really can't really fly without automation.

We need to hire real pilots that don't need automation to fly. I know they were all qualified to fly but by what standards? Knowing which button to push?

And when persuasion failed, the next thing to do should have been to take control, especially if one thinks that the conduct of the flight is becoming dangerous. It was the (possibly subconscious) decision to defer actively taking control until after the Captain returned - by which time the situation had got significantly more dangerous, and the PNF himself seemed to have been confused into indecision - that I was referring to.

@bubs - There you go again with "No pilot would X", and throwing around accusations of incompetence - the PF was a highly-qualified sailplane pilot, and to the best of my knowledge gliders don't have automation. Yes, he lacked training in high-altitude manual handling, but that's a long way from "not knowing how to fly". As such, a more likely explanation was that he was overwhelmed by the situation - compounded by startle effect.

As we touched on not long ago, even pilots who are considered to be super-competent can, typically when under significant pressure, make horrendous mistakes - probably the most infamous being the KLM Captain (Chief training Captain on the 747, no less) who tried to take off without clearance at Tenerife in 1977. So a pilot doesn't need to be incompetent to foul up, but - and this is one of the reasons I respect the responsibility you lot carry - in aviation you only need to foul up once at the wrong time to end a career, a reputation, and hundreds of lives.

OK DW they were both totally competent pilots. You must be right because somebody signed them off to fly without the captain in the cockpit. I am sure everybody agrees with you.

Interesting problem, but it's hard to find an answer beyond personal opinions and sensitivities. Why did PF pull into a stall? Even the Human Factor Group at BEA didn't find a convincing answer. He maybe thought of an overspeed situation. But how did he come to this conclusion? And why didn't PM stop this catastrophe?

Were they incompetent? They passed all tests, and there were no incidents that we know of. Where they competent? Well, at least the lack of situational awareness and bad CRM doesn't show Air France as a breeding ground for good practices.

I think (speculate) that Bonin had an acute attack of fear of falling down, i.e. panic (the professional term "startle factor" is just an euphemism). That's something pilots (I'm not one) probably don't talk about very much, because people who like to fly don't suffer in any meaningful way from it, it's trained away, and experience does the rest. But I'm asking if somewhere in the old "reptilian" brain regions something is still screaming (but not heard): "That's dangerous now, leaving the ground!".

I also wonder if it's a factor that Bonin previously was on vacation with his wife (fiancee?) on board. BEA noticed his nervousness in the 2 hours preceding the event. So maybe his mental state wasn't completely in "pilot mode", and the professional barriers broke down more easily.

wozzo;

On July 27, 2011 when the 3rd Interim Report came out with the flight data and we saw for the first time what actually occurred, I posited the notion that the PF increased the pitch because that what he was taught in his last (A320) sim session when given this problem. I maintain that the memory drill for UAS is confusing and poorly-written. It has in fact been modified prior to the accident, clarifying how the drill will be done, as has the way it is taught since the accident.

IIRC, his training for the UAS event was right after takeoff. The memorized pitch attitude is 15° and TOGA for those circumstances. Rather than climb on board the another hamster wheel, the original post is here.

Many disagree with this notion but I have seen no other explanations with greater plausibility and lots of psychological etc explanations which may or may not be true. I believe that he believed he was doing exactly as he was trained, uncertain though the stick inputs were, but did not have the experience to know what was about to happen to the energy of the aircraft. If he had pulled to 5deg as the checklist seems to indicate, (and then when above MSL or circuit altitude, level off for troubleshooting, which is what cruise altitude already is), I think it would have not resulted in the stall. I think he kept pulling because the airplane wasn't at 15° - all in all a series of inputs that speak to uncertainty and hesitation.

As I have pointed out numerous times, likely in all eleventeen threads on this accident, cockpit discipline, meaning their SOPs and CRM, fell apart instantly and that in my view is the root cause of the accident because, by following SOPs, (ECAM drills, paper drills, status, etc etc) and using correct CRM procedures to maintain discipline and sort out the problem before independently leaping into (unknown) individual actions, the accident could have been prevented because there were a number of points along the pathway to the stall that would have altered the course of this accident had such been employed.

Again as I have pointed out numerous times, a UAS event is NOT an emergency and does not require instant, un-coordinated, undisciplined action. It is not an engine fire, a depressurization, an hydraulic failure etc. The airplane itself does not 'care' what the airspeed indication is.

I am certainly not going to argue the "competent-incompetent" case. I have been in and seen too many things in 35 years of flying tranports and had sufficient personal "lessons" offered by the airplane I was flying to ever place myself in a position of judging. However, the basics of successful transport flying are, (and have never wavered from being) Standard Operating Procedures, and, since late eighties, Crew Resource Management, and these were/are no doubt heavily emphasized at AF as at all other carriers, neither of which this crew carried out when it came time to do so. I am unconvinced of "startle" - everyone is 'startled' to begin with - I have experienced a massive hydraulic failure on the same equipment and yes, it was initially startling but one reverts to training and deals with the ECAM accordingly. I have no idea why it came apart so swiftly and we'll never know. All we can do is re-emphasize what would have saved this airplane, this crew and these passengers, because this was not an emergency and there was no requirment to do anything other than ensure the airplane was stable while the ECAM drill was done according to Airbus SOPs. A pitch-up to 5° would not result in a stall so even if the PF had done the drill correctly, the accident likely would not have occurred. Anything after the airplane was stalled is untravelled territory and nobody can offer advice except that which is already in the books, specifically, if you have a high rate of descent that cannot be arrested by pulling back, you are stalled and need to unload the wing and reduce the angle of attack to unstall the wing, and then be very gentle on the pull-through.

All of this and more from many others exists in the AF447 series of threads. I genuinely hope we are not on another hamster wheel.

You can not blame training on pilot actions because pilots should know before the airline job how to handle an airplane. They should just need differences training and SOP's for that airline.

Really don't want to start the hamster wheel again, but ...

… I remember that, and it would tell us that Bonin indeed had a plan (if the fatally wrong one). But just for clarification: That wouldn't explain the behavior *after* the stall warning went off (considering hat Bonin had a few seconds before realized that he indeed was climbing), would it?

wozzo, please see my above post which I have edited and added remarks.

The best we can hope for is realistic suppositions as to "reasons why". There is nothing on the CVR that would settle this beyond the improbability of another's interpretation of the words.

When we first tried out the UAS checklist in conversion training it became very apparent that it was confusing. It still has that potential but we now have an accident that may settle some minds as to what to do. But I would never, ever pull a transport aircraft even to 5deg pitch with a UAS event and said so a couple of weeks after the accident, because it destabilizes a stable airplane. Leave pitch-and-power alone because the airplane was fine moments before the data got lost. The systems will sort themselves out during and after the ECAM actions but the airplane itself as a physical entity had all the energy and thrust it needed to continue to destination, without airspeed indications etc etc. There are numerous alternate ways, long discussed, in how one might determine speed and maintain altitude with such indications lost.

Lest anyone shudder at the re-arguing of this view, fear not. It's done.

At high altitudes no pilot would have a pitch even approaching 5 degrees. They went over 20 so of course stalled. They were of course fully qualified pilots on their airline. Makes you wonder doesn't it?

....makes me wonder what the Captain was doing when he could more usefully have been in his seat.

Guys - the mods merged a thread from R&N into this one. There was nothing in that thread that was not covered in this one - or the previous ten threads on the subject. I highly recommend we leave it be.

MO, he needs to not exceed duty time, therefore three pilots are required. He can not be on duty the whole flight. It is illegal for over an 8hr flight.

True but it didn't have to be just then and there are some oddities to the events. At least one of the pilots was anxious for his return and questioned the delay in returning and there is no mention in the released transcript of his reference to being bell'ed back or having just got his head down. Still, no need to upset Dozy ;)

Hi PJ2,

Good to see this October Inquest discussion, including your two posts, finding its proper place in Tech Log.

Thanks for reminding us all of the deficiencies of the UAS memory drill (and even the written procedure) current at the time, and the probability that it encouraged the initial pitch-up.

As I've said before, I also wonder if the APPARENT sudden loss of about 300 ft of altitude (due to the removal of correction for airspeed when the IAS went AWOL) might have provoked a knee-jerk (of the wrist) response. But the realisation that this was just another of those UAS events should quickly have dawned, followed by a return to the familiar pitch-attitude for cruise flight. As you say, simply maintain the status-quo...

Inappropriate initial reaction is one thing, but what happened after AF447 had completely vacated FL350 climbing was irrational and inexplicable in a competent pilot who had spent many hours monitoring the flight instruments in the cruise and step-climbs on dark nights - much like the one in question.

Question : If the PF was consciously following the prescribed procedure for UAS - then why did he not, at any point, tell his colleagues he was doing so?

In fact one of the overriding perceptions of the sequence as a whole was that there was never at any point a co-ordinated effort to troubleshoot and apply procedure. When the PNF stated "you're going up", the PF did not respond with "I'm following UAS procedure" - which would in all likelihood have unlocked the mystery for the PNF and allowed for corrective action.

As a non-pilot I am constantly and sympathetically aware that I cannot feel the visceral hold to the idea that there must have been some reasonable explanation for the actions of the PF. I accept that there's a possibility that he was applying a half-remembered UAS procedure, but for the life of me I cannot understand why he would not say he was doing so.

A Somewhat Different View
 

The aircrew actions in the AF447 accident seem strange to those of us looking back on this accident.

There are a few observations I would like to make about the situation that this crew faced. I think the known facts do not contradict this view, but I am working from memory and it's been a while since I reviewed the accident, so feel free to correct me where I stray from the facts.

First, let us start with the PNF, Robert. He had just been awakened from sleep by the Captain and had been told that the guy flying the aircraft would be in charge. He was undoubtedly awake, but I suspect he was suffering from sleep inertia and was not fully "with it." When the A/P and Autothrottle disconnected, he had been sitting in the seat for about 10 minutes. He was aware of the mishandling of the aircraft, particularly the upward roll of the altimeter numbers and tic marks but was really not mentally locked on to the actual altitudes they were going through, thus his strange comment, " You are going up, so go down." Maybe it is just my old fashioned way of flying, but I would have thought he would have said something like 'You are 1500' above assigned altitude. Get the nose down!' His reluctance to take control might well have been a result of his sleep inertia which he would have been aware of. Likely he did not yet trust himself to perform.

Then there is Bonin, the PF. He was suddenly thrust from quietly monitoring the instruments into NOISE.
The cavalry charge, then the C chord altitude alert, and a few chirps from the stall warning on top of that. No sooner did he grab the stick and begin to correct the roll angle when the aircraft over-responded in an unfamiliar way and he began a roll oscillation. (Alt2b Law was now in effect) The aircraft was in roll direct. He apparently he had no prior experience in flying in Alt2b Law in the simulator at altitude and likely, no experience in flying in Direct law at altitude. As a result, his mental model of the aircraft response was out of calibration and his control inputs were well beyond appropriate for roll.

I do not know how many of you have experienced a roll PIO in any setting, or for that matter any PIO (pilot induced oscillation). From my one roll PIO experience in an early simulator, I found it to be extremely startling and attention getting and I would expect that Bonin experienced a similar feeling of startlement and concern. This likely fully focused his attention on the roll problem to the exclusion of almost everything else. His solution to the problem was to try to get ahead of the oscillation. It eventually worked after 30+ seconds of fighting the aircraft, but one of the reasons it worked is that the roll response was decreasing as the aircraft slowed. (The preferred solution is to stop aggravating the aircraft)

It is very likely that Bonin's nose up efforts were initially inadvertent as he struggled with the roll, then later, deliberate as he either reverted to seat of the pants flying or started flying the flight director. His thought processes were not logical by then and he was focused on a narrow part of his surroundings to the exclusion of almost all else.

By this point in time Bonin was in full fight or flight mode and Robert was getting concerned as well. They were not working together and the aircraft was departing controlled flight and they were entering test pilot territory.

My personal opinion is that if Bonin had not overcontrolled the aircraft initially, the accident would not have happened. He would have begun to follow his training, however imperfectly and the crew would have begun to work together sufficiently well to continue the flight. The lack of experience in direct law at altitude was a key contributing factor that allowed a roll PIO to develop, and from there, it all snowballed downhill.

You could be right, but the query I have regarding this is that - while my only personal experience of the flight deck is in a simulator - the spring loading on the sidestick means that if roll is all you want to control then the springs will hold you steady at zero in the Y axis unless you make an effort against them. Even in Alt2b law, the aircraft will try to maintain the last commanded pitch so there is no need to keep pulling back to maintain it.

The sidestick on an A330 is a far cry from the kind of cheap controller you can pick up for your computer - it's a chunky piece of kit!

Hi DW,
Correct.
However some some crews move their seats after take off into a more "comfortable" position. This places their hand and arm in a completely different position relative to the side stick. I think that's why Bonin inadvertently applied light back pressure whilst he struggled to hold wings level in Alt Law.

Since the crew didn't turn off the FD switches, when the FDs automatically reappeared, they were in modes HDG & VS. The crew seem to have simply continued to follow those erroneous commands.

From memory - the BEA looked into that and established the seat position from the post-crash marks on the seats recovered.