AF447 wreckage found

[takata]

Hi BOAC,

Originally Posted by BOAC

I suspect that like me, none of the contributors here of late actually know what Air France taught for recovery from the approach to a stall in the A330 in those days, nor how much 'reliance' was instilled in crews in the infallibility of the AB in not 'letting you stall'.

Maybe a look at AF A330 documentation can give you a hint about that?
In fact, it is in English and they used Rev.24 of the procedure with three cases:
- lift off (low speed)
- flight phases after lift off (low speed)
- high altitude

This "Infallibility" legend of the Airbus "will not let you stall" is certainly not part of this aircraft documentation, check by yourself:

[BOAC]

Originally Posted by takata

This "Infallibility" legend of the Airbus "will not let you stall" is certainly not part of this aircraft documentation, check by yourself:

- That was a silly comment. Are you seriously suggesting that AB would have put those words in the manual? I would not even expect Ziegler to do that - spout it, yes, but print it? No.

What is your airline experience as pilot, by the way - hours, types? Your ability to produce manuals, graphs and quotes is indeed impressive, but...................

Has the thought crossed your mind that some of the

some instructors (both SFIs and TRIs)

most probably would have had similar words to the AB page in their manuals - and STILL taught otherwise? Your faith is touching, to say the least, and to come from a world where everyone (and, of course, everything) performs faultlessly must indeed be wonderful.

[sebaska]

BOAC:
Why ad hominem?

Besides, where it's written that those 'some instructors' are/were AB330 instructors? Or from AF?

[bearfoil]

If uncommanded by PF (or a/c), the climb may have been addressed with PF's 'Nose Down inputs'. I think BEA have not specifically timed those.

Likewise, he would not advance Throttles (he did not).

The second STALL WARN, could actually be predicting the STALL that resulted from loss of energy in this climb (which thus far is not described as to origination). The AoA (not necessarily PITCH) would increase as the Plane slowed, independent of elevators that had lost their effectiveness anyway. As the Plane dropped Nose (Either as a result of controls OR STALL), the AoA would reduce, hence TOGA and 'backstick relief' as the a/c "STALLED". At this point, had PF done nothing, he may have recovered? (No TOGA, no 'back pressure' held). Saying the pilots did not know they were Stalled is presumptuous.

At this point it is not determined if NU inputs are slight (inadvertent) pulls by PF, and not a back (climb) command. It could indeed be a trained APPROACH TO STALL recovery, at a very inopportune time.

[Lonewolf_50]

If uncommanded by PF (or a/c), the climb may have been addressed with PF's 'Nose Down inputs'. I think BEA have not specifically timed those.

Bear, to be clear, that depends on the duration and frequency of nose down inputs as counters to nose up inputs (per how a Sidestick works) which detail is still vague. The BEA seems confident that at least initial climb was initiated by a nose up movement of SS.

The second STALL WARN, could actually be predicting the STALL that resulted from loss of energy in this climb (which thus far is not described as to origination). The AoA (not necessarily PITCH) would increase as the Plane slowed, independent of elevators that had lost their effectiveness anyway.

Huh?
The climb slowed the plane. Since power was not initially reduced, climb came from pitch up, so ... AoA change was due to ... drumroll ... pitch up. You with me? It has been suggested that when TOGA was selected later in the event chain, nose pitched up more due to how planes like this fly. This tends to increase AoA if not countered by the appropriate pitch adjustment (n-d) to accompany the power increase. This is Flying 101, and would be called for if in alternate versus normal law. There is evidence that pilots were aware of being in alternate law. Not sure of the granularity with which BEA can parse the data from FDR ... we shall see. I suspect it correlates well enough.

[bearfoil]

Sorry Lonewolf.

I am posting on the other thread, and forgot to mention I assume a substantial UP Draft for the climb, consistent with Harry Mann's proposal that the Right wing drop may be a Tip Dip into Vertical Airmass by Left wing. See, if uncommanded, PF would input Nose Down, to maintain altitude (I reasonably assume he did not want to climb!).

Had a stroke last year, and sometimes (usually?) I leave out key bits. And include some extraneous ones!

[jcjeant]

Hi,

You with me? It has been suggested that when TOGA was selected later in the event chain, nose pitched up more due to how planes like this fly.

At the altitude where was the plane .. with the throttle setting he have (before the PA disconnect) I suppose the difference of push by the engines will be minimal when throttles set to TOGA .. and so the nose up effect will be no significant
I understand that at low altitude a TOGA set will produce a significant nose up ...... not at high altitude.

[RetiredF4]

There seem to be a lot of different stall recovery procedures on the market from the time before AF447.

@takata and Iceman

I think, the revised stall recovery procedure, implemented due to some LOCīs without successfull recovery by A+B aircraft made a lot of sense, so it seems to be short sighted to assume the old procedures had nothing to do with the training before AF447 and therefore the applied procedures of AF447. The emphasis of the old procedures was placed on speed increase and maintaining altitude, whereas the revised procedures aim on reducing AOA firsthand and deal with altitude when AOA and speed allows further maneuvering. There are a lot of differences to the new procedures and the procedures as coppied from FCTM A330/A340 (think itīs from Cathay Pacific) from 2006. I admit, i dont know wether those procedures underwent a further change between 2006 and AF447 loss.

Bolding by me

FCTM A330/A340
Non-normal Operations 8.20.15
Operating Techniques REV 2 (25 JUL 06)

STALL RECOVERY
In alternate and direct laws, an aural stall warning “STALL, STALL, STALL” sounds at low speeds. Recovery is conventional. Apply the following actions simultaneously:

· Set TOGA thrust
· Reduce pitch attitude to 10° below FL200 or 5° at or above FL200
· Roll wings level
· Check that the speedbrake is retracted
Below FL200 and in the clean configuration, select Flaps 1. If ground contact is possible, reduce pitch attitude no more than necessary to allow airspeed to
increase. After the initial recovery, maintain speed close to VSW until it is safe to accelerate. When out of the stall condition and no threat of ground contact exists, select the landing gear up. Recover to normal speeds and select flaps as required. In case of one engine inoperative use thrust and rudder with care.

The aural stall warning may also sound at high altitude, where it warns that the aircraft is approaching the angle of attack for the onset of buffet. To recover, relax the back pressure on the sidestick and if necessary reduce bank angle. Once the stall warning stops, back pressure may be increased again, if necessary, to get back on the planned trajectory.

Again bolding by me to highlight some points.
First the old procedure is not named stall approach recovery, but stall recovery. It deals with the situation AF447 was in, alternate law. The actions should be applied simultaneously. Set TOGA thrust. Reduce pitch to 5° above FL200.

That is quite a difference to the new wording

– Apply nose down pitch order on the side-stick
– If needed, reduce thrust in case of lack of pitch down authority
– Ensure wings are level

because a reduction of pitch can be achieved by a reduction in NU force or, if pitch would be less than 5° and PF is focused on the number 5° pitch, he may be motivated to increase pitch to 5°.

The last para is interesting too. It disqualifies the stall warning at high altitude to being just the point of buffet onset (not being stalled already, which might well happened). Again here "relax pressure on SS, no word of ND input. And further on ..... "once stall warning stops, back pressure may be increased again....... not reapplied again.


And the summary of the new procedure says it all (bolding by me)

• Spirit of what is the new procedure
 One single procedure to cover ALL stall conditions
 Get rid of TOGA as first action
 Focus on AoA reduction

If the PF judged the first spurios stall warning at the beginning of the climb as not valid, but the second one at FL375 as valid, then he acted in accordance with the old stall recovery procedure described above by
-applying TOGA and simultaneously reduce backpressure on SS, which for sure was not enough, because a full ND input would have been appropriate. But where do you find a ND input in the procedure of 2009?

By the way, it has to be emphasized that those procedures (the old and the new one) are derived from thinktanks originating from A+B.

I dont think i would have followed this old procedure if trapped in this situation, because my expierience would have hopefully overridden this "nonsense procedure. But did the PF ever expierienced a real stall in a jet?

[Mr Optimistic]

But if a stall wasn't recognised, why should stall recovery training be relevant ? Ditto THS authority in the absence of sustained ND commands. Mind you, it would be reassuring if they did train it properly in any case, would seem a pity to spend money training and to cock it up. AS SLF I am surprised that with all the instruments and automation to help, it was possible for 3 experienced and trained crew not to be made aware through appropriate indications and prioritised warnings that the a/c had stalled. Of course leaving the stall warner activated when off the ground might have helped, though in this case even that could be doubted.

[takata]

Originally Posted by RetiredF4

There seem to be a lot of different stall recovery procedures on the market from the time before AF447.

But only one relevant at the time of AF447 is what I already posted above from Air France A330 2009 FCOM (Rev.24).
Anyway, I don't understand how one may consider that PF actions at this second stall warning (which lasted 50+ seconds) could match any published stall procedure at all without completely twisting the facts. Neither TOGA nor sustained pull-up would be part of it.

[Lonewolf_50]

Recency of training.

What stall warning response maneuvers were last practicied by either pilot in the cockpit during their last simulator training session?

This is a human factors issue that I've seen raised in more than one aircraft mishap investigation, including one I was personally involved with.

[RetiredF4]

Takata
But only one relevant at the time of AF447 is what I already posted above from Air France A330 2009 FCOM (Rev.24).

Is there also a FCTM from Air France available with the relevant paragraph like that one posted by myself?

Anyway, I don't understand how one may consider that PF actions at this second stall warning (which lasted 50+ seconds) could match any published stall procedure at all without completely twisting the facts. Neither TOGA nor sustained pull-up would be part of it.

Isnīt the new generation of pilots focused on procedures and SOPīs and a strict obedience of those procedures, whereas my generation was challenging those procedures and their application dependent on the relevant situation and based on their own experience (and improving those by doing so)?

And based on that statement (also it has a ? at the end) and the old stall recovery procedure (not stall procedure, you misnamed probably) the actions of AF447 reflects the application of this procedure to detail, without twisting any facts. We might not understand, why they continued the aplication of this non functioning procedure for so long, but again, see above.

It would be a better approach to question the implementation of the old procedure instead of twisting the application on behalf of the wrong outcome.

[Lonewolf_50]

retired F4: spot on, and not to mention the training norms and experiences for that particular procedure and situation.

Getting at that may shed some light, but it may also be difficult to do. Fear of blame seems to be infesting corporate culture.

[RetiredF4]

That there is a big problem is recognized by the industry

See flightsafety.org from apr 2011

The more iīm wondering, why we tend to disregard or to deny this problem on the expert level.

[Zorin_75]

Originally Posted by RetiredF4

the actions of AF447 reflects the application of this procedure to detail, without twisting any facts.

Hmm. In which way does maintaining nose-up inputs until pitch attitude ends up at 16° reflect "Reduce pitch attitude to (...) 5° at or above FL200"?

[bearfoil]

Approach this accident as if the Pilots were not stupid, and Franz starts to make perfect sense. (Probably not just to me!)

[RetiredF4]

Quote:
Originally Posted by RetiredF4
the actions of AF447 reflects the application of this procedure to detail, without twisting any facts.

Zorin_75 Hmm. In which way does maintaining nose-up inputs until pitch attitude ends up at 16° reflect "Reduce pitch attitude to (...) 5° at or above FL200"?

It does not at all, and we should ask the question how come?
Maybe that is the reason?

The aural stall warning may also sound at high altitude, where it warns that the aircraft is approaching the angle of attack for the onset of buffet. To recover, relax the back pressure on the sidestick and if necessary reduce bank angle. Once the stall warning stops, back pressure may be increased again, if necessary, to get back on the planned trajectory.

Together with
- lack of training in manual flying,
- lack of training in flying in this altitude ,
- lack of training in manual flying in this altitude in alternate law

continue with

- at night
- in WX /maybe turbulence
- without airspeed indication
- sudden stress

and you might find lots of reasons, why this recovery attempt with a meanwhile outdated procedure failed.

[Mr Optimistic]

So you think they knew they were stalled ?

[bearfoil]

If they were unaware of Stall, they would select TOGA exactly, why?

[RetiredF4]

Mr. optimistic
So you think they knew they were stalled ?

I stated that before already. They recognized the first intermittent stall warning as a valid indication due to applying too much NU input (like pulling the A/C into the stall warning AOA) at begin of climb and reacted with ND input (reducing the climb rate to 700 fpm). There was too much NU SS input after the disengagement of AP+Athr due to inexpierience and lack of training, the reaction of the aircraft with the amount of pitch was a surprise. The correction with ND input was not big enough (PX comfort, not to want overreact again,...)

The second stall warning was honored with the stall recovery procedure by applying TOGA thrust, however pitch reduction was again either not applied correctly or not applied enough or other reasons (cant think of any though besides of thrust, which i myself cant qualify, although it is of concern in oficial airbus publications dealing with new stall recovery procedure) caused the pitch to increase to 16°.

What else than a reaction to the stall warning should have motivated the crew to apply TOGA thrust?