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AF447 wreckage found

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AF447 wreckage found

Old 4th Aug 2011, 23:57
  #2601 (permalink)  
bearfoil
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For many reasons, not the least of which I find to be BEA propaganda, Nonsense PR from All Three principals, and a lack of sincere consideration, Long haul flight on AF has become (unwittingly) problematic

OPINION: The fact that remote mathematical odds are thrown about, I consider it whistling past the graveyard. The loss of an autopilot for any reason (and I have NOT accepted UAS or ICE had effall to do with it) means that one of three potential Pilots may be responsible for an aircraft that has ventured into mathematical probabilities of a demonstrable ONE IN THIRTY THREE HUNDRED OF crashing to the surface of the EARTH.

The odds of losing an auto pilot (disconnection as well as through malfunction) might be, one in one hundred? The chance of encountering bunk MET in ITCZ is likely what, ONE TO ONE?

So, 1/33 UAS
1/100 AP LOSS
1/1 BUNK MET

I see a chance of ONE in 3300 of coming to serious grief on AF.

Tell me again how utterly safe AVIATION IS?
 
Old 5th Aug 2011, 05:23
  #2602 (permalink)  
BRE
 
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As this thread keeps growing faster than I can keep track, bear with me if these questions have been asked before:

1. Had the PNF pressed the takeover button, would the PF have been able to re-take control?

2. Is it normal for a crew at AF:
- not to be using standard calls (maybe even in English), but informal French throughout?
- to be addressing each other with the familiar "tu" in spite of the age and authority gradient?

3. Just for comparison, what is the official cockpit language in say KLM or LH?
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Old 5th Aug 2011, 05:38
  #2603 (permalink)  
RWA
 
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Confess to still being ‘bugged’ by the issue of the THS going to ‘full up.’ Unfortunately the BEA doesn’t say much about it in the latest report – and what it does say is rather contradictory.

Page 10 - "At 2 h 10 min 51, the stall warning 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) began a movement and passed from 3 to 13 degrees pitch-up in about 1 minute and remained in the latter position until the end of the flight."
That’s just a repeat of the section in the earlier report.

Page 75 - "Despite some nose-down inputs, the PF maintained nose-up inputs overall. Pitch attitude fluctuated between 11° and about 18° and the angle of attack between 11° and 23°. The THS began a movement that was consistent with the PF’s inputs and reached 13° nose-up about a minute later. It should be noted that in alternate law, the auto trim is still active. On the other hand, it is difficult for the crew to know the trim position and there is no warning to the crew that it is moving."
The important thing there, to me, is that autotrim was still in operation.

Page 77 - throughout the flight, the movements of the elevators and the THS were consistent with the pilot’s inputs,
That’s the contradictory bit. As far as I can see, from the chart on page 111, the THS movements simply weren’t ‘consistent’ with the pilots' inputs at all. Indeed it appears only to have made the one movement – to ‘full up’- during the whole episode.

On Page 111, the pale blue line under ‘STABILIZER POSITION’ appears to show that it didn’t move at all at first. Then, at about ‘2.10.50,’ it began to pull up. This movement seems to have started during a period when the PF (shown as ‘CAPTAIN’) was putting in quite a lot of small movements both ways – none of which seem, on the face of it, to have been large enough to trigger such a huge movement by the THS? The THS movement finished (i.e. reached ‘full up’) at about ‘2.11.50. From then on the THS seems just to have remained at ‘full up,’ and didn’t respond to any of the further stick inputs made by both the pilots?

Can anyone with more knowledge of the aircraft and its systems – bearing in mind that the BEA says that autotrim was still in operation - explain why the THS would have behaved in this (on the face of it, very strange) way?

Is it possible, for instance, that the autotrim was responding not to the pilots’ inputs but to the very low Indicated Air Speed, or to other irregularities ‘reported’ by the sensors?

Last edited by RWA; 5th Aug 2011 at 05:52.
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Old 5th Aug 2011, 05:51
  #2604 (permalink)  
 
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Sounds like Airbus safety could be enhanced by low time pilots getting high altitude hands on flying so they don't zoom 3,000 ft into a deep stall when the autopilot fails. Also explain to them that holding back on the SS once in a deep stall is not a good idea. Just a thought.
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Old 5th Aug 2011, 05:53
  #2605 (permalink)  
 
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Authority gradient??? In Europe the FO's think and act as they have the same status as the captain, and the EU captains accept that. Had many attitude behavior problems flying with European FO's, but when the S hits the fan they say "You're the captain, it's your problem"…
Until they understand the "Leaders and Followers" rules, conflicts in the cockpit will exist and flight safety will be jeopardized.
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Old 5th Aug 2011, 09:12
  #2606 (permalink)  
 
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Originally posted by RWA ...

Can anyone with more knowledge of the aircraft and its systems – bearing in mind that the BEA says that auto-trim was still in operation - explain why the THS would have behaved in this (on the face of it, very strange) way?
I believe the outcome is due to the THS being 'g' driven. In other words, the SS command was given that allowed the actuator to take the elevator to maximum NU, but the expected 'g' didn't occur and the THS moved to (try) correct that situation.

In explanation - the THS will always attempt to neutralize the position of the elevator, and if necessary readjust according to elevator demand.

If I am wrong, you will soon find out.
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Old 5th Aug 2011, 09:33
  #2607 (permalink)  
 
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My understanding from the Perpignan report is that, with autotrim in operation, the THS only moves when the elevator goes past the neutral position: nose down elevator will command the THS to move more nose down. The elevator follows the (g-driven) SS orders. So a small nose-down command from the SS that causes the elevator to move from nose-up to less nose-up without going to nose-down will not cause the THS to move.
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Old 5th Aug 2011, 10:33
  #2608 (permalink)  
 
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1. Had the PNF pressed the takeover button, would the PF have been able to re-take control?
Yes, pressing the take over button himself. Last one pressing has commands.

2. Is it normal for a crew at AF:
- not to be using standard calls (maybe even in English), but informal French throughout?
No. This shows much stress.

- to be addressing each other with the familiar "tu" in spite of the age and authority gradient?
Standard use. At AF the last in F/O will use "tu" in cockpit with the most senior pilot in airline if they're to fly together. It spares a few syllabs. After all, "you" can mean both "tu" and "vous", it's practical to decide for only one word and "tu" helps forming a team spirit. All crew uses "tu", except in cabin where "vous" is used. Sometimes F/A use "vous" talking to captain, mostly when they're white/grey haired.
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Old 5th Aug 2011, 10:43
  #2609 (permalink)  
 
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Horrified

As a very part time passenger and model plane pilot, I have followed this threads with interest. The CVR and FDR data is horrifying - I would have thought that professional pilots would have behaved very differently in such a situation. I could imagine myself as thrown into that situation and doing no worse than the PF did - perhaps better when it came to stick inputs. That is scary.

On a recent flight I noticed the issue mentioned in a couple of comments - that is the loss of sense of aircraft orientation. I could have sworn the plane was level but when I looked out saw thet the wings were banked and the plane was turnning left. I can only imagine how hard it must have been for these pilots to sense what the plane was actually doing withouit any horizon on a pitch black night, with what appeared to be unreliable instrumentation.

I guess that is when training and professionalism is meant to take over...
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Old 5th Aug 2011, 12:55
  #2610 (permalink)  
 
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For those who have flown the A330:

How many key strokes (steps) does it take to call up the F/CTL ECAM System Page on the SD. This screen shows where the rudder and THS are, and what the spoilers are doing, what spd brks are or aren't doing, and a prim/sec status. It also looks to tell you which hyd system is up or down as related to a given flight control.

Does this screen get auotmatically pre-empted by rising ECAM alerts, or does is stay active once selected?

Background thinking to my question:

About 20 years ago, something as simple as switching Radio Freqs went from a simple manual task of turning a button here or there, to a process which requires opening a screen and typing in freqs. (This was in the SH-60F). As I had never had trouble with switching radios by hand, I looked into this and noticed that it takes MORE time and steps to switch radios via software. From a pilot task loading perspective, this was idiotic. It appeared to me one of many "solutions" looking for a problem. On that aircraft, the sole FBW control surface was the horizontal stabilizer. (Sorta like the THS in A330, but different). A single, small gauge in the lower center of the instrument panel told you where the stab was at all times. (It was mostly controlled by an auto trim feature). This gauge was a cross check instrument, not a primary scan instrument. You only needed it if things were a bit wrong with the electronics. There was also a manual control that overrode the electro-trim and allowed you to fix its position as needed.

Back to THS on an A330.

I don't know if the crew in AF447 would have thought to look at where their THS was ... but ... if the PNF had wanted to, how many steps in sequence would it take to discover where that control surface was positioned?

Last edited by Lonewolf_50; 5th Aug 2011 at 13:05.
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Old 5th Aug 2011, 14:59
  #2611 (permalink)  
RWA
 
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mm43, HazelNuts39, thanks so much for the informative replies.

Quoting HazelNuts39:-

My understanding from the Perpignan report is that, with autotrim in operation, the THS only moves when the elevator goes past the neutral position: nose down elevator will command the THS to move more nose down. The elevator follows the (g-driven) SS orders. So a small nose-down command from the SS that causes the elevator to move from nose-up to less nose-up without going to nose-down will not cause the THS to move.
I read the BEA's Perpignan report (on a accident back in 2008) but missed the point you very kindly brought up. To quote part of the report:-

"From 15 h 44 min 30 the automatic trim function displaced the stabiliser as far as the electric nose-up thrust stop (- 11 degrees). The stall warning sounded at 15 h 45 min 05. The nose down commands applied by the Captain on the sidestick brought the elevators, due to the load factor, to the neutral position, without however pushing them to the stops. Consequently, the trimmable stabilizer did not move even though the flight control law was normal. From 15 h 45 min 15 until the end of the flight, the automatic trim function remained unavailable. In fact, the direct law was active from 15 h 45 min 15 to 15 h 45 min 40 and the Abnormal attitude law phase 1 (without auto-trim) remained active till the end of the flight.

"Footnote:- The elevators must go beyond the neutral position before the auto trim function adjusts the position of the stabilizer.

"When the stall warning sounded, the Captain reacted by placing the thrust levers in the TO/GA detent and by pitching the aeroplane down, in accordance with procedures.

"The nose-down input was not however sufficient for the automatic compensation system to vary the position of the horizontal stabilizer, which had been progressively deflected to the pitch-up stop by this system during the deceleration."
So, as I read that, in order to get the THS even to start moving back to a sensible angle, the Perpignan pilots (and later the AF447 ones) would have needed to shove the stick full forward and hold it there for quite a while, until the THS 'accepted the situation' and started moving back from 'full up.'

But, of course, on AF447, every time they attempted that, the airspeed increased and they got another 'stall warning.' And presumably thought they were 'doing it wrong' (what, apart from an engine falling off, can be more serious than an impending stall?) and instinctively relaxed the stick pressure.......

It'd be interesting to know whether Airbus, Air France, or the BEA had warned pilots that this sort of 'impasse' could occur; and indeed had occurred, as far back as Perpignan in 2008? I very much doubt it........

Anyway, thanks again - I now know, to my own satisfaction, the primary causes of this latest accident. And, in my view, they weren't entirely, and possibly weren't even mainly, 'pilot error.'


Last edited by RWA; 5th Aug 2011 at 15:14.
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Old 5th Aug 2011, 15:06
  #2612 (permalink)  
 
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Have the investigators (BEA) stated that the zoom climb was commanded by the pilot (stick) or is the jury still out considering that a computer function did it unrecognized by the pilot?

I focus on this early event as a possible critical causal factor needed to take a benign failure condition (temporary lack of reliable airspeed) to a severe condition.

To me this is a critical finding, because we can'y elliminate all failure conditions (ala loss of airspeed) etc. We are left with strengthening a minimization factor like pilot training. If there is another critical area that can be worked on in this causal chain that would greatly minimize a repeat of the event chain leading to a fatal accident.
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Old 5th Aug 2011, 15:13
  #2613 (permalink)  
 
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Unfortunately, this was an Airbus accident and this thread will no doubt go on for another One Hundred Thirty plus pages ! Had it been a "real" airplane, "case would've been solved" a Hundred pages ago. Naturally, IMHO.
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Old 5th Aug 2011, 15:17
  #2614 (permalink)  
 
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The causes are independent of the plane

IMHO The causes are :

1 The decision of the PF to climb, yet the PNF has told him the temp. was to high;
2 The decision of the PF to re take control from the PNF without annoucement and to climb again yet the PNF has urged him to nose down.

These two decisions of the PF are not a reaction to any information from the plane.

They came from his will and only his will.

The first decision leads directly and logically to a stall;

The latter decision prevented the PNF from recovering the plane.

None of these decision should have come from a Professional Pilot.

These decision had nothing to do with training nor CRM, design etc.

Furthermore, the Captain had a nasty feeling proved by his odd question : "Do you have your licence ?" to somebody that had made the journey with him from Paris.

I really think that it should be investigated to understand in which psychological or physical conditions he was.
I believe that the very short time between the entering of the Captain and the level 100, barely allowed him the time to understand that the PF was climbing against all skills. When this was established, then the PNF could took the control again under the Capt. authority. But it was to late.

I believe that tço many people here and in the press don't make the distinction between the period before teh PF re take control of the plane and the short sequence after.
The BEA should have divided the time around this KEY action:

- Because the PNF needed the authority of the Capt to take control except if he were Rambo.

- Because when the Capt. enters, he doesn't see the end of the stall caused by the first decision of the PF. He lives a NEW sequence just after the PF had RE taken the control and that he climbed again, entering in a new stall.
Too short for the Capt to understand.
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Old 5th Aug 2011, 15:19
  #2615 (permalink)  
 
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Cool

Hi,

Can anyone explain me this (it's extracted from the BEA report french edition page 23)



 Enregistreur de paramètres - FDR

 Marque : Honeywell
 Modèle : 4700
Numéro de type (P/N) : 980-4700-042
Numéro de série (S/N) : 11469


JJFFC

Last edited by jcjeant; 5th Aug 2011 at 15:36.
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Old 5th Aug 2011, 15:57
  #2616 (permalink)  
 
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The more and more I read the more concrete it seems that the "zoom" was initiated by PF input to the SS not as a result of AP disconnect (which was a point of confusion to me). This is a significant deviation from the previous theory that the AP "wound out" until it reached the end of it's capabilities and handed the plane off in an entirely unstable condition.

Am I correct in my understanding that the climb was in fact initiated by proactive input and that the subsequent trim changes are a result of the auto trim responding to the SS inputs?

Given the very serious issues involved in approaching max altitude even with full instrumentation (let alone under the circumstances involved) any decision to gain altitude would appear to be fundamentally incorrect and display a complete lack of basic airmanship. What pilot would knowingly fly an airplane with degraded systems closer to coffin corner? Did not the senior pilot on the flight deck have a clear responsibility to forcibly (in the verbal sense) take command if required?

I have been unable to find reference to the captain questioning the PF's credentials (was this before the upset? before the flight?). If the captain had enough concerns to actually make a comment then how does he allow this individual to actually be the PF when he retires from the cockpit????
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Old 5th Aug 2011, 16:29
  #2617 (permalink)  
RWA
 
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Quoting Lonewolf50:-

Back to THS on an A330.

I don't know if the crew in AF447 would have thought to look at where their THS was ... but ... if the PNF had wanted to, how many steps in sequence would it take to discover where that control surface was positioned?
Looked it up (can't find the photos again) and the conventional (non-electronic) A330 setup looks pretty good. Big trimwheels either side of the central console, and (I checked ) they're servo-assisted, and actually move!

However, the wheels don't give you the pitch angle; they just have the 'usual' setup, white marks every 15 degrees or so. Apparently there are gauges beside the wheels that give you the angle - how well illuminated they are, and how easily you could read them at night, I just don't know.

Point that occurs to me, though, is that the autotrim was still operating? So, even if the pilots had thought to check the trim settings and maybe wind the wheels forward a bit, presumably the 'systems' would just have wound the things back to 'full up' again?

Last edited by RWA; 5th Aug 2011 at 16:41.
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Old 5th Aug 2011, 16:32
  #2618 (permalink)  
 
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@SLFinAZ
I have been unable to find reference to the captain questioning the PF's credentials (was this before the upset? before the flight?). If the captain had enough concerns to actually make a comment then how does he allow this individual to actually be the PF when he retires from the cockpit????
Page 73 of the BEA Interim report:

A little after 1 h 52, the turbulence stopped. The copilot drew the Captain’s attention to the value of REC MAX, which then reached FL 375. The Captain made no comment and, a few moments later, he woke the second copilot, said he was taking his place, and asked the copilot in the right seat if he had a commercial pilot license. He thus ensured that he was qualified to act as relief and implicitly designated him as relief pilot. This question to the copilot probably meant that the issue of the relief pilot for the Captain had not been raised during the briefing before the flight.
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Old 5th Aug 2011, 16:34
  #2619 (permalink)  
 
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Originally Posted by jcjeant View Post
Hi,
Can anyone explain me this (it's extracted from the BEA report french edition page 23)

 Enregistreur de paramètres - FDR

 Marque : Honeywell
 Modèle : 4700
 Numéro de type (P/N) : 980-4700-042
 Numéro de série (S/N) : 11469
What do you want "explained" ?
It's the Honeywell part number and serial number of the FDR memory module.
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Old 5th Aug 2011, 16:36
  #2620 (permalink)  
 
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Cool

EDITED

Cross posting

I have been unable to find reference to the captain questioning the PF's credentials (was this before the upset? before the flight?). If the captain had enough concerns to actually make a comment then how does he allow this individual to actually be the PF when he retires from the cockpit????
English report N°3 page 73
A little after 1 h 52, the turbulence stopped. The copilot drew the Captain’s attention to the
value of REC MAX, which then reached FL 375. The Captain made no comment and, a few
moments later, he woke the second copilot, said he was taking his place, and asked the
copilot in the right seat if he had a commercial pilot license. He thus ensured that he was
qualified to act as relief and implicitly designated him as relief pilot. This question to the
copilot probably meant that the issue of the relief pilot for the Captain had not been raised
during the briefing before the flight
.
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