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AF447 wreckage found

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AF447 wreckage found

Old 26th Jul 2011, 09:56
  #2161 (permalink)  
RWA
 
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Quoting Mr Optimistic_

5. 'nose up inputs' ?
Many thanks, Mr O, edited!
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Old 26th Jul 2011, 10:09
  #2162 (permalink)  
 
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RWA

For the umpteenth time
pilot applies standard ‘stall avoidance’ procedure at that time (apply TO/GA power and seek to minimise altitude loss).
that is !

Give it a break your theory and misinterpretations are wrong, you are like a broken record and never reply to the posts that contradict you. You wait a few days / posts and post the same rubbish again. If you have nothing NEW to say don't say anything.

You need to read and digest how the airbus flight controls work not how you think they work.
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Old 26th Jul 2011, 10:33
  #2163 (permalink)  
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Quoting iceman50:-

that is !

Give it a break your theory and misinterpretations are wrong, you are like a broken record and never reply to the posts that contradict you.
On the contrary, I answered your last (also somewhat abusive) post, with a source, in my Post 2086 above.

"Investigators have been left attempting to explain why the crew of Air France flight AF447 failed to recover the Airbus A330 from a high-altitude stall, a predicament which has been the subject of a recent revision of safety procedures.

"The revision concentrates on placing greater emphasis on reducing excessive angle of attack - the critical characteristic of a stall - rather than the classical approach of training pilots to power their way out of a near-stall with minimum loss of altitude.

A formal document detailing the rationale for the revision points out:
"There have been numerous situations where flight crews did not prioritise [nose-down pitch control] and instead prioritised power and maintaining altitude."

Operational experience has shown that fixating on altitude, rather than the crucial angle of attack, can result in an aircraft stalling.
Revised stall procedures centre on angle-of-attack not power

If Flightglobal (and I) are wrong, please inform us what the recommended procedure actually was back in 2009, and what changes were made recently?

Last edited by RWA; 26th Jul 2011 at 10:57.
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Old 26th Jul 2011, 10:44
  #2164 (permalink)  
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Originally Posted by iceman
For the umpteenth time Quote:
pilot applies standard ‘stall avoidance’ procedure at that time (apply TO/GA power and seek to minimise altitude loss).
that is !
- maybe have a glance at http://www.pprune.org/tech-log/41537...procedure.html ? It may be of interest to you.
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Old 26th Jul 2011, 11:10
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BOAC

It is NOT new, it has just been re-emphasised by Airbus Boeing regulators etc as some pilots / checkers were thinking like RWA as in maintain ALTITUDE. The procedure being continually mentioned by RWA was recovery from low speed NOT a stall and even that did NOT mention MAINTAIN altitude. There again perhaps I have been teaching and checking it incorrectly for the last 10 years on the A330 / 340 and been taught stall recovery incorrectly for the 30 years before that.
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Old 26th Jul 2011, 11:12
  #2166 (permalink)  
 
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(In this connection, I dislike the tendency of some (particularly that newspaper article) to suggest that the PF was ‘inexperienced.’ If you look him up, you’ll find that he had the best part of 3,000 hours in his logbook, including about 850 on the A330).
For a Cessna 172 pilot, this is "experienced." For an air-transport pilot, not.
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Old 26th Jul 2011, 11:54
  #2167 (permalink)  
 
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Making stuff up

RWA:

1. ‘Signoff’:- AP/ATH disconnect, pilot takes manual control, corrects an uncommanded bank, and begins flying ‘pitch and power.’
So where is the evidence there was any attempt at pitch and power at this point??? You have simply made this up. We are simply told there was a roll correction and nose up input. Followed by a 3000 foot climb...

There is no mention of any attempt to control power until some point later when the misguided TO/GA selection was made. At least that's the only mention of any power adjustment I can find in any segment of the BEA note until much later when power was reduced.
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Old 26th Jul 2011, 12:04
  #2168 (permalink)  
 
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Hi,
Originally Posted by RWA
3. ‘The stall’ – stall warning sounds, pilot applies standard ‘stall avoidance’ procedure at that time (apply TO/GA power and seek to minimise altitude loss).
Where did you get that?
There is NO such a "Standard stall avoidance procedure" for A330 due to NORMAL LAW flight envelope protections. If you want to refer to what is really relevant, you'll need to check into the "Abnormal Operations" related to ALTERNATE LAW, where stall avoidance procedures are described.

Here, you'll learn what the correct procedure is 3.04.27 page 6 (Rev 18, 2003). There is two cases: low speed and high altitude.
a) low speed: Apply TOGA and (at the same time) reduce pitch angle (angle-of-attack).
b) high altitude: Relax back pressure on sidestick (reduce angle-of-attack).

Where is then this "standard [imaginatory] procedure" you were talking about for high altitude stall warnings:
=> Apply TOGA and maintain back pressure on sidestick !?!
Both actions recorded are wrong for the situation: TOGA is not needed, neither is this pulling up.

This was the second stall warning, the first was ignored or responded by a pitch up if volontary applied. There is no trace of your:
1. ‘Signoff’:- AP/ATH disconnect, pilot takes manual control, corrects an uncommanded bank, and begins flying ‘pitch and power.’
Pitch was wrong and power was not unlocked (no trace of this in BEA narrative). You are retaining bank correction without pitch correction. Why are you making up this stuff?

Same about this:
Originally Posted by BEA
At 2 h 10 min 51, the stall warning was triggered again. The thrust levers were positioned in the TO/GA detent and the PF maintained nose-up inputs. The recorded angle of attack, of around 6 degrees at the triggering of the stall warning, continued to increase. The trimmable horizontal stabilizer (THS) passed from 3 to 13 degrees nose-up in about 1 minute and remained in the latter position until the end of the flight.
Around fifteen seconds later, [~0211:06]
How can you say that you don't know when THS moved to 13°?
This is obviously timmed starting at or closely after 0210:51 and then ended also close to 0211:51.

Originally Posted by RWA
If Flightglobal (and I) are wrong, please inform us what the recommended procedure actually was back in 2009, and what changes were made recently?
Of course you are completely wrong.
What changed was the emphasis on Pitch rather than Thrust, as large thrust increase may have an adverse effect on pitch reduction at low speed. At high altitude, it doesn't change a glitch as stall warnings would be triggered at the onset of buffet, likely at an already high Mach, without many excess thrust available, hence only a question of AOA at the limits of the safe flight envelope.
Check by yourself the relevant part of A330 FCOM in use before 2009:


Last edited by takata; 26th Jul 2011 at 12:45.
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Old 26th Jul 2011, 13:09
  #2169 (permalink)  
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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'. It is worth noting that unlike the impeccable Iceman, some trainers were NOT teaching things correctly - in the UK at least.. This is the first para from post#14 in my link (with my emphasis) from April 2010

A very good document from British CAA that has a lot in common with the new procedure:

Applicability: RETRE, TRIE, TRE, SFE, TRI, SFI
Effective: Immediate
STALL RECOVERY TECHNIQUE
1 Recent observations by CAA Training Inspectors have raised concerns that some instructors (both SFIs and TRIs) have been teaching inappropriate stall recovery techniques. It would appear that these instructors have been encouraging their trainees to maintain altitude during recovery from an approach to a stall. The technique that has been advised is to apply maximum power and allow the aircraft to accelerate out of this high alpha stall-warning regime. There is no mention of any requirement to reduce the angle of attack – indeed one trainee was briefed that “he may need to increase back pressure in order to maintain altitude”.



Wait until 29 July?
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Old 26th Jul 2011, 13:29
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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:


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Old 26th Jul 2011, 14:23
  #2171 (permalink)  
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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.
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Old 26th Jul 2011, 14:49
  #2172 (permalink)  
 
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BOAC:
Why ad hominem?

Besides, where it's written that those 'some instructors' are/were AB330 instructors? Or from AF?
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Old 26th Jul 2011, 15:28
  #2173 (permalink)  
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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.

Last edited by bearfoil; 26th Jul 2011 at 15:41.
 
Old 26th Jul 2011, 15:55
  #2174 (permalink)  
 
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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.
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Old 26th Jul 2011, 16:01
  #2175 (permalink)  
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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!
 
Old 26th Jul 2011, 16:26
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Cool

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.
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Old 26th Jul 2011, 17:19
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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 LOC´s 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 it´s 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?

Last edited by RetiredF4; 26th Jul 2011 at 18:49.
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Old 26th Jul 2011, 17:43
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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.
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Old 26th Jul 2011, 17:54
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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.
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Old 26th Jul 2011, 18:03
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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.
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