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AF447 final crew conversation - Thread No. 2

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AF447 final crew conversation - Thread No. 2

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Old 8th Mar 2012, 15:42
  #101 (permalink)  
 
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First of all, "PULL" is TAUGHT as a partial in approach to STALL. It is a version of "Maintain Altitude".

Secondly, on the PFD already was ALTERNATE LAW in AMBER. Piloting an a/c in the conditions 447 found herself takes more than second grade reading skills.

Failing more data, I will never understand the PF's actions. Never. Without context, and perhaps there is none, all that aft stick is bizarre. Equally mystifying is the utter lack of "conversation" on the flight deck. I do not believe it was so, there is more to hear. If wrong, I will apologize in time. The Human Factors group is stuck with the hot potato, No? To make conclusions, they will have to support them. In this support I think more shall be revealed.
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Old 8th Mar 2012, 16:12
  #102 (permalink)  
 
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PFD messages.


on the PFD already was ALTERNATE LAW in AMBER
You confuse PFD with ECAM....
ECAM message is F/CTL ALTN LAW(PROT LOST)

The only messages you will see on PFD is RED "MAN PITCH TRIM ONLY"
or AMBER "USE MAN PITCH TRIM" or a FMGS related or EFIS switching message.
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Old 8th Mar 2012, 17:01
  #103 (permalink)  
 
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One mo' time

Good grief.

I thot most here agreed that the crew

- Pulled versus "neutral or even down command on the stick
- Had poor coordination
- Couldn't figure out they were stalled because the jet didn't shake, rattle and roll all that much

The pitot heat needs to be examined, for sure. But it is not going to be "found" as a primary "cause" by the investigators. The jet can fly real fine with only attitude and "manual" power settings while working out the UAS problem, right?

It's gonna be all pilot/crew error.
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Old 8th Mar 2012, 17:22
  #104 (permalink)  
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Lyman;
Re, "Without context, and perhaps there is none, all that aft stick is bizarre."

Without spending too much time reviewing old ground, I had some time ago posited the notion that the PF was executing one of the memory items in the UAS drill.

In the BEA Second Interim Report pgs 54 & 54, Section 1.17.2.4, it is noted that the UAS event was included in the 2008-2009 recurrent training season. The training included a booklet, the contents of which are briefly described in this section.

The training script for the recurrent simulator session in which the UAS event was included and which the PF First Officer had taken on February 2 2009, (the PM First Officer had received this training a couple of months earlier), required that the aircraft remain in Normal Law with no warnings triggered.

The UAS scenario used in this simulator session was a loss of airspeed information just after takeoff.

In such a case, the safe conduct of the flight is impacted and the memory items of the UAS drill are to be executed.

After ensuring that the autopilot, flight directors and autothrust are set to OFF and if below thrust reduction altitude (nominally either 1500ft AGL or more recently, 1000ft AGL), TOGA thrust is set and the initial "safe" pitch attitude is set to 15deg NU.

At slightly higher altitudes (thrust reduction altitude to FL100) the thrust levers are set to the "CLB" (climb) detent and pitch is set to 10deg NU. Above FL100 and if the safe conduct of the flight is still impacted, pitch is set to 5deg.

The last item in the memorized group states that once the aircraft is above circuit altitude or MSA, (Minimum Safe Altitude), the aircraft is leveled off for troubleshooting.

The FCTM (Flight Crew Training Manual) dated February 2007, though not the legal operational document (only the FCOM is) states that if the safe conduct of the flight is not impacted, the memory items are not to be executed and the crew must reference "part 2" of the QRH UAS checklist for correct pitch and power settings. In other words, present pitch and power settings are maintained while the QRH is brought out and the checklist read by the PM.

As pointed out by Owain Glyndwr, the failures resulting from the loss of airspeed information are graceful and do not present controllability problems. Loss of airspeed information does not require immediate action when in stable, level flight. So, what explains the immediate action?

I think the PF concluded that with the loss of airspeed information the safety of the flight was at immediate risk and was simply executing what he recalled from the earlier simulator session.

As the BEA Third Interim Report states, neither cockpit discipline nor SOPs were followed, and in combination with the effects of the immediate, strong pitch-up commands and subsequent aircraft response taking the aircraft out of stable, controlled flight, I think this prevented them from perceiving and then assessing what was happening.

The situation became immediately confusing as to why the airplane was behaving the way it did, (two momentary stall warnings, due strong pitch-up commands) and the returning airspeed information after about 28 seconds, and a likely clearing of ECAM faults as the airspeed data returned to normal, presented confusing signals to the crew. By this time the airplane was approaching the stall at the apogee of the climb.

Once the pitch-up occurred, a cognitive dissonance rapidly emerged from the differences between expected aircraft behaviour and what they were seeing/hearing. Putting it differently, the pitch-up was expected to be the "correct" response but it wasn't producing the expected stability. Normal perception of the stall warning was blocked because they were trying to resolve cognitive expectations with what was happening).

There seemed to be the expectation that the aircraft would respond at cruise altitude the way it would right after takeoff. This speaks to training and experience issues of manually flying transport aircraft at cruise altitudes and of knowledge and understanding of high altitude, high Mach number flight.

I'm speaking here as a pilot of course, but I think these are reasonable, if not at the moment theoretical, human factors.

gums;

Precisely.

Issues arising from this may be the loss of stall-warning below 60kts and some form of audible signalling when the trim is moving but I think the designers/engineers had a reasonable expectation that the aircraft would not be flown in these regimes by competent line crews, and that every contingency imaginable could not be designed against, not, at least, without prohibitive and difficult-to-justify cost.

I think the one very significant issue is however, the design of the UAS drill and QRH checklist which does not reflect with sufficient clarity what is stated in the FCTM. All we need do is review the PPRuNe contributions on this to see that the matter is indeed conflated even among those who fly the airplane. The fact that 36 other crews did not do what many here have claimed to be the "correct" response in cruise, (if above FL100, pitch up to 5deg) is evidence that there is a significant disconnect here. In fact I think even Airbus is confused about this.

Last edited by PJ2; 8th Mar 2012 at 17:41.
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Old 8th Mar 2012, 18:40
  #105 (permalink)  
 
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Gratuitous Bravo!

PJ2 wrote, among many sensible things:
I think the PF concluded that with the loss of airspeed information the safety of the flight was at immediate risk and was simply executing what he recalled from the earlier simulator session.
Bravissimo! Well-done.
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Old 8th Mar 2012, 19:01
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Without in the least dissenting from what Gums and PJ2 have written, and accepting that the drills were not exactly clear, it is I think worth reminding ourselves that 5deg pitch/CLB is not, of itself, deadly.

At 02:10:50 or thereabouts the aircraft was at 6 deg pitch, 5 deg AoA, climbing gently. The bank had been substantially zero for 15 secs past. The airspeed was 216 kts; which is about 1.17Vs. No stall warning. of course.

Had they stopped at that point or gone to level flight we would not be having all these discussions.It was the second pull up to 17 deg pitch that mattered and which is, for me, completely incomprehensible.
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Old 8th Mar 2012, 19:04
  #107 (permalink)  
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Well, this is entirely speculative and unsubstantiated! It is only one of a number of reasonable explanations of why the PF almost-instantly pitched the aircraft up to an attitude that, in a transport aircraft at cruise altitude, I still find frightening, and like everyone else I'm just trying to explain/understand. Greatly-reduced damping effects of much thinner air in high altitude flight requires that one be very gentle with the airplane, just like Davies* says. It is no wonder that the stall warning blipped twice, as the AoA at which the stall warning occurs (in Alternate and Direct Laws only) is between 1 and 2 degrees higher than cruise flight AoA's.

Aircraft inertia will continue the physical trajectory of the mass and "fly through" any immediate response by the aircraft to increased lift resulting from an increase in pitch and thus the AoA increases in any such swift changes in pitch, here, to the point of triggering a couple of stall warnings.

Frankly, while such handling is an abuse of the airplane which exhibits a lack of understanding of high altitude flight it's no big deal because the airplane isn't stalled. But none of this explains the continued pull on the stick after the stall warning continued sounding. Any response should have been a full-forward stick to achieve about a 12 to 15 degree nose-down attitude to unstall the airplane...that results in a descent rate of around 15,000fpm.

When the speed begins to increase indicating exit from the stall, a very gentle pull on the stick is required to avoid another high AoA resulting from the higher positive g's during recovery and subsequent second entry into the stall.

This is, or should be, all pretty basic stuff, thus the questions surrounding the continued pull. I think the confusion surrounding the ceasing of the stall warning and then its reappearance is understandable but the extremely high descent rate and unwinding altimeter, (the (older) standby altimeter was going around the dial once every 2 seconds in the sim), should be sufficient to have indicated a fully-stalled aircraft but they only realized that at around FL100 or so.

It's all been thoroughly discussed in seven previous lengthy threads but sometimes a review is helpful.

Owain Glyndwr;

Thank you for this reminder...I fully agree with you that a 5deg pitch attitude (about 2.5deg above normal cruise pitch) is not itself a problem, (I had originally thought and had posted that it was but again learned and changed my views!).
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Old 8th Mar 2012, 19:38
  #108 (permalink)  
 
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The second pull to 17 was accomplished by a pilot who had done that before, and not experienced any fatal result. He was repeating what the a/c and the UAS drill taught and were teaching. Pull, TOGA. It's in the book, and not contra indicated. Remember the "second Pull to 17" happened just after the STALL WARN blared, as it had before. Duff speeds? Is it Real?

Because it defeated a stable attitude is IRRELEVANT. You and I know that, but PF's screen was not recorded, remember? Did he purposely leave a stable attitude, only to STALL? I suggest, not on purpose.

A33Zab. Thank you, yes the ECAM. What is more important to a flying pilot, his instruments? His duty to the ECAM and fault resolution? An interesting discussion? Where should the cue appear? On ECAM, along with dozens of other bitches, or on the life and death of what he knows the a/c is doing?

In a very real way, there is a built in conflict on this flightdeck, if only "philosophical". Get out the book, address each warning, alert, team the return to unannunciated complaints? Or handle the a/c? There was little CRM, if any, shall the PF do it all, or must he choose? PFD? The fact that at any given time in this four minutes a plan and some teaming would have helped, the confusion was inconquerable, each opportunity ignored, misunderstood, or wasted.

imo
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Old 8th Mar 2012, 20:04
  #109 (permalink)  
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Lyman;

As has been reviewed on numerous occasions, the SOPs to deal with an abnormality come under the heading (as you probably know) of aviate, navigate, communicate then deal with the abnormality or emergency. Control of the aircraft is first assured, then ensure terrain clearances, then communicate internally (announcing the emergency/abnormality and calling for the drill or checklist, then when all is done, communicate with ATC then the flight attendants/passengers.

Except for the rejected takeoff and TCAS/GPWS/Stall warnings, no emergency and certainly no abnormality (which this was), requires immediate action and never without crew coordination.

In the RTO for example, crew coordination may be just the announcement "Reject!", followed by the simultaneous closing of thrust levers, selection of reverse, monitoring/applying full brakes and ensuring ground spoilers are up. At a minimum, announcing the drill or checklist ensures awareness and subsequent coordination and appropriate action.

In abnormalities, on the Airbus the PM calls the ECAM name of the abnormality, the PF calls for "ECAM Actions" and the PM reads (silently) and carries out the ECAM checklist items, confirming any non-reversible actions with the other crew member before actioning them. Then the STATUS page is then checked for system/aircraft unserviceablilities and possible performance considerations.

Where/when required either by the ECAM or company SOPs, the QRH is then brought out for further responses to the abnormal. The entire process including high levels of CRM is heavily emphasized in all initial and recurrent simulator sessions, check flights and in the aircraft manuals.

It is against all this that the response of both the PF and PM is astonishing and incomprehensible even given cockpit gradient and lack of command assignment and consequent assessment and decision-making issues. It may be unfair to observe (because I wasn't there, not because it isn't reasonable to expect), but upon initial pitch-up without announcement from the PF which is non-standard and highly irregular behaviour I would have expected the PM to announce, "I have control", level the airplane, call for the UAS checklist and sort it out with the captain later, on the ground.
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Old 8th Mar 2012, 20:39
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Hi PJ2. Again I must salute your patience and wisdom. I do think, though, that in reiterating the proper procedures we can be distracted by just how emergent was the crisis, helped not in the least by the apparent thick skulled behaviour of the pilots, which we both acknowledge. We have the same target, but I think we approach the understanding from different perspectives. Your words describe "best case, best practice." Here, clearly, such was not the case, not with the information we have to hand. I cannot know why the PF started to handle the a/c so quickly, but he did, and right or wrong, I think he had a motive, one he thought was sound. That he should not do that is patent, as we know, again your patience trumps my volatility. I do not have the experience you have, so it may be easier for me to achieve confusion than even our PF. My sense of the cockpit is that there were two opinions on board, that of the PF, whose behaviour we know was incorrect, and the PM, whose only mistake appears to have been that he allowed the PF's opinion to prevail.

Throughout this three year long thread the evolution appears to be that the pilots were not up to it, and the a/c was wasted due to precipitous and unfounded actions. It has been far too long since anyone has written what these three pilots were up against. We cannot be at all sure that the conditions extant at the twenty seconds before and after were conducive to standard action, imo.

grateful to you
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Old 8th Mar 2012, 20:49
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Originally Posted by A33Zab
The only messages you will see on PFD is RED "MAN PITCH TRIM ONLY" or AMBER "USE MAN PITCH TRIM" or a FMGS related or EFIS switching message.
Interim Report #2 para. 1.6.11.5 (page 47 in the English edition) shows the changes on the PFD between Normal and Alternate law.
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Old 8th Mar 2012, 22:08
  #112 (permalink)  
 
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With all due respect,

Lyman:
The second pull to 17 was accomplished by a pilot who had done that before, and not experienced any fatal result. He was repeating what the a/c and the UAS drill taught and were teaching. Pull, TOGA. It's in the book, and not contra indicated.

I beg to differ. As was just recently posted (and many times before), that procedure is strictly reserved for UAS near to the ground and for windshear (near the ground). It is patently wrong at high-altitude cruise. That's why it's now being trained, I do believe.

Your words describe "best case, best practice."
The only practice that would have saved them.
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Old 8th Mar 2012, 22:20
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as

"That's why it's now being trained....." qed.

Point being, it was the second time he made that "mistake". Was there a Windshear warning? W/S appeared on ACARS, as did TCAS. Monkey hear, monkey do.... Besides, Pitch is filtered through the computer in AL2, none of his aft stick had as robust a result as had his ROLL. This in itself could have been the confusion's source, one of. Twitchy in Roll, molasses in PITCH. Acute Roll inputs, and chronic in Pitch? Was he treating them the same, respect wise? If he had forgotten and expected both axes to respond the same, his overcontrol in Roll could have incested his PITCH commands? Vice versa?
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Old 8th Mar 2012, 22:24
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@HazelNuts39:

Absolutely agree! Thanks for the addition
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Old 8th Mar 2012, 23:18
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Lyman, Re: UAS

Perhaps this will help refresh your memory, a 2006 Airbus presentation that contains some readable data.

http://www.iag-inc.com/premium/Airbu...ableSpeeds.pdf
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Old 8th Mar 2012, 23:39
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Hey TD

Thanks for the link. Despite the cartoon format, I see a serious side, and my attempt to shorten and more specifically define the challenge remains. "Speed" is not as descriptive as "Airspeed", and at each opportunity to quantify the problem the manufacturer continued to use full script. I think the acronym is an apt one. As PJ2 points out, BEA picked it up. Whether concurrent or original, the acronym remains descriptive and has become part of the dialogue, I think in a good way. No?
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Old 9th Mar 2012, 08:45
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lawyer, asked to define the difference between "unlawful" and "illegal" by the judge in a criminal court case could not define the difference. "Ah", said the judge, "I have always thought that the one was "against the law" and the other was a sick bird!"
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Old 9th Mar 2012, 20:13
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Lacking information

Hi,

We are with limited factual information on the case. There are some reasons, we understand.

Trying to understand the "non understandable" reasons of PF (persistent NU) and in a simulation exercise (in doing so, trying to cover
ALL POSSIBLE reasons) and "last but not least" considering that RHS was not recorded (one of "inputs" to PF) i would ask: What kind of information he could see to justify his actions?

The SS sitck to the extreme left was coherent. (bank angle indications were reliable). What kind of possible misleading information could be coherent with (some) PF actions with respect to pitch?

Last edited by Jetdriver; 10th Mar 2012 at 22:25.
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Old 9th Mar 2012, 20:58
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RR NDB

Reselected PFD's to acquire the BIRD, coupled to reselected autoflight, which drank in 90 knots and showed profound NoseDown? There was a great deal of mystery and yellow tarps on the avionics bay (recovered).

V/sel: 5000 fpm DOWN, etc. The fact remains PF should have relinquished control. The fact also remains he did not. What was he looking at, surely not all blue? Mostly Brown? Why would he ignore PM: "TJIS< here here, we are climbing, go down." He Did Not descend. He saw all blue and continued to pull?

What did Air Caraibes show on the selected PFD during its uncommanded climb?

Down? Nothing?
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Old 10th Mar 2012, 00:28
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Lyman,

In my post to you, I was not referring to the acronym relative to speed. The message I was conveying was the fact that in 2006, it was documented exactly what to do if one encountered unreliable or erronous air speeds at high altitudes. The correct procedure was available then. It is what PJ2, gums and others have been saying. 2006 is prior to AF447.
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