Does it matter? The point is that the correct thing to do was monitor and correct as necessary. Immediately grabbing the PFC and making large inputs prior to properly assessing the situation is more than likely to make a bad situation worse.

Drilling that fact in until it overrides the instinctive "startle response" is the only way to combat it.

We know what he did, but not why he did it.

Hazelnuts39

HazelNuts39 We know what he did, but not why he did it.


That is my point. Except to say, it appears he was correcting the flight path, at least to me. To say what he did was incorrect is an opinion, at least at first. It is also "substantiated"'after the fact, with data unavailable to the pilots.

That's just it - we can never know for certain, but given the evidence we do have, we can consider some possibilities as more likely than others.

The reason I don't believe the PF was confronted with a wildly divergent display from his colleague in the LHS is in part because I know that's not how the system works, and also because at no point is a discrepancy between the two PFDs and ISIS commented on by any of the crew - including the Captain, who after he arrived had a clear view of all three.

The reason I believe the pitch was commanded by the PF and not the automatics is because the DFDR traces of the stick input and pitch attitude tally almost perfectly up until the point of stall.

The reason I believe the displays were consistent with having lost speed information is the PNF's call at 02:10:15.9. ECAM is for systems-level troubleshooting, not maintaining or regaining control. The PFDs should be enough for that.

Lest this be perceived as a defence of Airbus, I believe they should have been a lot more pro-active about replacing the Thales AA pitot tubes than they were, and should have been more forceful in pushing for high-altitude manual handling and stall training. I think Air France should have mandated all three flight crew to be present on long-haul ITCZ crossings until the problem was fixed. I also think their CRM training was in dire need of overhaul.

Lest this be perceived as a defence of Airbus, I believe they should have been a lot more pro-active about replacing the Thales AA pitot tubes than they were, and should have been more forceful in pushing for high-altitude manual handling and stall training. I think Air France should have mandated all three flight crew to be present on long-haul ITCZ crossings until the problem was fixed. I also think their CRM training was in dire need of overhaul.

Amen to that...

Having said that, I think it should be acknowledged that Airbus's response to the problem was to immediately form a working group with Boeing to tackle the problems of high-altitude stall across the industry. They deserve kudos for that.

I doubt it will convince everyone that Airbus does not deserve the brickbats thrown at them over the years, but I hope it will make some folk think twice.

Let's not get carried away. Shortly after the wreck, the airframer published a bulletin advising pilots to review their Stall recovery procedures.

Rather an oblique admission of disconnect...

Not really - taking the eye off the ball as far as high-altitude stalls went was an industry-wide problem.

The industry had collectively suffered what renowned test pilot and astronaut Frank Borman once described (referring to the Apollo 1 fire) as a "failure of imagination". Stall training focused almost exclusively on low-altitude situations, where the advent of high-bypass jet engines meant that with 5 degrees pitch and full power it was possible to get out of it (and every manufacturer trained almost exclusively for this scenario). The prospect of bleeding off speed towards the operational ceiling (where thrust was far less effective) was to all intents and purposes disregarded by all manufacturers and airlines.

Modern previous UAS-induced stall incidents happened during the climb phase - Birgenair 301 being the most notorious example, and that was a single pitot tube failure that would not have presented a problem to Airbus's design. The West Caribbean 708 MD-80 (not UAS, but rooted in failure to diagnose stall) should have been more of a red flag, but because the root technical cause was a little-understood issue with the anti-ice system, it seems that the industry was happy to leave it there. Colgan 3407 should have been a warning too, but the industry focused on the fatigue levels of the pilots involved (which was understandable) rather than questioning why the Captain would pull up into a stall.

Every Thales AA pitot tube-related incident prior to AF447 was successfully recovered by the crews, and as such it's somewhat understandable that notification to crews of the issue and a procedure for dealing with the temporary UAS situation would have been considered enough prior to AF447.

Let's not beat about the bush here - most pilots on here were incredulous when AF447 IR#3 came out and it transpired that the PF got locked into a "pull-up" mindset throughout the accident sequence. I last flew a real aircraft in 1993 and even I remember that pulling up at or near the safe operational ceiling is a big no-no. However, I'm also acutely aware that when the fit hits the shan, reason can go out the window no matter how competent you are. I've seen it in myself, I've seen it in my friends and I've seen it in colleagues. Thankfully I've never been responsible for the lives of a couple of hundred people at the time I temporarily lost the plot, but I can still remember the cautionary lesson I took while cleaning the metaphorical egg from my face.

I don't consider this crew incompetent and never have. In fact one of the first things I said when I joined this discussion almost two years ago was that I consider them to have been incredibly unlucky and to some extent poorly-prepared by the industry that employed them. This isn't a zero-sum game - you don't have to try to prove the aircraft design deficient in order to honour and respect their memories, we simply have to honestly assess what went wrong and make sure it can't happen again.

As far as I'm concerned the industry as a whole deflowered the canine here - Airbus and AF included - but they weren't alone.

Oh, and apropos of nothing, the C4 documentary I watched last night (and picked a lot of holes in) is available here:

Fatal Flight 447: Chaos in the Cockpit - 4oD - Channel 4

Without any agenda, Dozy, explain to me your thoughts on the degrade, and the retention of a familiar axis, and introduction of an unfamiliar.

What happens to 447 with degrade to Direct, and its 'trim only' Pitch inputs, manual. Zoom climb? A focus on small inputs, and those by hand? I personally see a potential for salvation. If only to gain time, less altitude, and reappearance of good speeds. I know, hindsight.

Wadda ya think?

Thanks

For what it's worth, I think the trim issue is fairly inconsequential - because the stall situation was not identified in time by the crew. As I've said numerous times, the autotrim had potential for salvation because with sustained nose-down on the PFC it would have corrected itself without needing to touch the trim wheels.

Maybe if there was an attempt to force the nose down and keep it there in the last minute I may feel differently, but the fact is that the PF was pulling up practically all the way down. As such, failure to recognise the situation and use CRM to remedy it is considerably higher on my list of priorities.

Fundamentally though, the existence of Alternate Law is to provide the pilot with handling characteristics as close to normal as possible despite degraded systems functionality, and to suggest taking that away because of one incident where it worked marginally against the crew (in response to the handling pilot making inappropriate inputs) would be throwing the baby out with the bathwater as far as I'm concerned.

Incidentally - something that the documentary clued me into that I hadn't considered before regards the sudden switch to pulling up on the part of the PNF (and confirmed by the Captain), and that was the sound of the GPWS "PULL UP" warning at 02:14:17.

[EDIT : I don't think I've mentioned this before, but I almost had skin in the game. A fellow musician and friend of mine almost boarded AF447 that day, but elected to stay in Rio for a few more days.]

You have been answered on that point already but you prefer to ignore the reality which allows you to camp on that false concept of your own.

If they lost the speed tapes at the time you mention, why the BEA is not mentioning it … or are you doubting the BEA now ?

It does not matter if it is a big X over half the screen or whatever it is, thete is a visual clue. Only it is not wort to be mentioned as contributing factor, and it was recognized.

We can turn in circles a hundred more times but it does not change any fundamentals. The pilots recognized the unavailability of information of the speed information. What they did not due is to follow with the appropriate actions.

We can discuss other visual clues, change the whole architecture of the flight deck, change the logic of the FBW system, add tactile clues, whatever.

In the end it has no effect as all these things still require the crew in charge to take the correct action to fly the aircraft. And that is what really was missing. To consequently think that the pilot is not the final authority and needs to be having the necessary education to do so in the end means to have the fully automatic aircraft.

We can only speculate on the nature of thinking wich lead to the inapropriate actions during the event. The way leading to those however are also cultural, but to understand this you must have lived in France as a foreigner.

In my opinion the real cause of this event lays very deep in the french way of doing things and no amount of changes on the technical side will change this and prevent such or similar events to happen again. We have hammered on Asian crews for causing loss of life on cultural factors but we fail to accept this as a reason for a 'western' crew.

The pilots recognized the disappearance of some speed symbols, not a disappearance of the indicated airspeed. They would have been much better served with such disappearance of the all speed scale. That some speed symbols disappear is NOT a cue to trigger the UAS memory items.

The system knew something was wrong with the indicated airspeeds as it decided to disconnect AP but did not think as necessary to advise the pilots for the reason it had disconnected that AP.

The most difficult part in a scenario of UAS is to realize first that there is a UAS.
As soon it is a recognized, the pilot switch to the requested procedure, in this case a memory item – No guessing.
Pilots are trained to apply procedures and are pretty good at it – It helps so much if they are given the appropriate GO signal that will guide them in the right direction.

The system knew but did not inform – What a waste.

You can all dress this up in whichever clothes you wish - the need for better 'control' systems on the AB, the way speeds are displayed, even badly written checklists, but the one big problem we have is the total illogicality of the response of PF in pitch and the apparent lack of 'command' (CRM if you will) from PNF.

These I feel will never be satisfactorily explained.

I hesitate to mention the 'O' bird, but I hear it flapping again.

An Indicator ?
 

For much of the event the THS was at full NU, IIRC. I believe that this was not commented upon by the crew. It may not be normally scanned even whilst it was within view of all. Is full NU "normal" in cruising flight ? (I think that I understand just how it may have reached this setting, but is that within what one might expect as "normal"?)

Linktrained
It always returns to the same point
Pull the stick (and sustained) at cruising altitude is heresy and lethal
Do not watch the flight instruments is evidence of a very bad practice (eg not seeing the trim wheels position.. altimeter .. etc ..)
The PNF is busy with a lot of things futile and foreign to maintains the aircraft's flight is another proof of poor training (first keep fly the AC .. and next investigate)
And this is common to all three pilots as they have the same bad training and same bad CRM
Like tell Mr Schramm in a interview (AF pilots manager) it was this night the" maximum of competence" in the cockpit
The key is to know what it means "maximum of competence" for AF and if it is comparable to the other pilots proficiency of major airlines ....

Only went that way after the aircraft was effectively stalled. On passing CLmax (AoA 9.6°) at 02:10:57, the THS had moved up only 1° from its cruise condition of about 2.7° NU. It was the continued NU on the SS that induced the THS to supplement the Elevator and head for maximum NU.

It would seem that neither the PF or PNF noticed the Trim Wheel moving - something I believe that wasn't in their "normal" scan, as in NORMAL LAW the THS is assumed to look after itself.

Even though the PNF announced the ALT LAW (Prot lost), the PF didn't acknowledge it verbally, and I think there has been a general consensus reached in these threads that neither the PF or PNF realized what the THS could do when other than in NORMAL LAW. By the time the Capt returned the majority of the THS NU had occurred, but like the other two, he probably never looked at its position or noticed that it was in the final stages of its movement.

bonjour, mm....

Your quote, :ok: "By the time the Capt returned the majority of the THS NU had occurred, but like the other two, he probably never looked at its position or noticed that it was in the final stages of its movement."

That requires a suspension of disbelief such that even I am challenged to entertain it....


So let me ask you the hypothetical question that Dozy inartfully dodged.

Say it is so, and the crew were virtually ignorant of the controls.

If the only Pitch inputs available had been small manual 'trim only' excursions, do you not think the crew would grok this trim at Auto/loss?

If, without any airdata, (computer selects Alternat 2b), the a/c required pitch inputs, the fact that the THS is limited to three degrees NU would have completely eliminated the possibility of zoom, and STALL.

The controls Law architecture seems on the one hand to be mindful of PITCH in DIRECT LAW, but relies completely on ELEVATOR PLUS THS in an emergent and handling environment very touchy, when it should be MINIMAL.

IOW, without airdata, the need for very cautious PITCH input is clear, seemingly tailor made for DL PITCH, but it does not go there, it stops short, and allows the type of misdirected SS inputs.

IN DIRECT, the SS is abandoned (pitch axis), perfect for UAS, but goes to the vulnerable AL2 instead.

AIRBUS had the foresight to provide for careful PITCH work in DIRECT, suitable for UAS, but in the actual UAS condition, it allows 'mayonnaise'.

Qu' est-ce que c'est?

Merci bon chance

Yes, correct. I used the word "attitude" loosely but not in reference to what the fbw laws attempt to maintain. To put it straightforwardly, they maintain Nz and roll rate - no input, no change, so attitudes are maintained. IIRC, in Normal or Alt1/2 Laws, a small back pressure on the stick is required to maintain altitude beyond 33deg bank. In Direct, it's a regular airplane and some NU correction is required when banking to change direction.