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-   -   AF 447 Thread No. 10 (https://www.pprune.org/tech-log/493472-af-447-thread-no-10-a.html)

Lyman 8th Nov 2012 15:29

Sounds good....

We discuss here a pilot who demonstrably has lost the "plot", and his partner, who evidently was easily pleased that things were acceptable, in the midst of a wild ascent.

Are you willing to suspend your strict definition of "pilot"? In the interest of entertaining a possibility? Once the climb established, and control was lost (i define upset as three seconds after loss of a/p and at first SW), it becomes difficult to retain textbook definitions, yes?

What manner of 'control' involves the stick venturing to and fro, a constant (net) NU, and Stall Warn bracketing a climb of three thousand feet in restricted airspace?

Can we agree that loss of SA may have at least potentially involved spatial disorientation?

rgds

HazelNuts39 8th Nov 2012 16:01

Hi Lyman,

How did he manage to control roll if he was not looking at the attitude indicator? How did he determine that he had lost (lateral) control at 02:11:31? How did he manage to maintain 15° NU until he also lost longitudinal control?

Lyman 8th Nov 2012 16:24

Because he had confused the two axes, as the aircraft had taught him to, in the thirty seconds it took to kill them all? Have you never fixated on one cue, ignored another? Believed one, and not another? Always trusted dials and completely eliminated sensory? I think he fixed on Roll.

Isn't it clear that whatever he saw v/v Pitch, he pulled anyway? Aren't we looking for reasons to explain this lapse?

This is my point. In AL2b the aircraft behaves schizophrenically, by definition. It required a skill that this pilot had not only not practiced, but may not even have been aware of. Machinbird has explained this, and his comments are instructive. I think Roll had PF totally consumed, so by inferring that he saw AI and "should have" mastered AOA, is presumptive. This flight was lost in the first fifteen seconds, and simply by degrading into a Roll mode that demanded the complete attention of both pilots, such that they lost the awareness of flight path that may have saved them.

No one needs 'twitchy', not in those circumstances....

HazelNuts39 8th Nov 2012 17:08

Hi Lyman,

You don't address my third question: How did he manage to maintain 15° NU until he also lost longitudinal control?

Lyman 8th Nov 2012 17:53

'Maintain' 15 degrees suggests he could suss attitude, and that 15 was what he wanted. That also happened post Roll issues, no? Given that he may have selected TOGA, is it possible he was comfortable with a) 15 is acceptable, the a/c is Stall protected, or b) he was flying "g pants".

Maintain is the key word, for it suggests that however he sussed the flight path, his Pitch was 'appropriate', in his opinion. He also may not have been aware of the value.

rudderrudderrat 8th Nov 2012 18:02

Hi HazelNuts39,

How did he manage to maintain 15° NU until he also lost longitudinal control?
Probably by following these erroneous FD commands.

Time FD MODE
2 h 10 min 08 ALT CRZ HDG
2 h 10 min 08 - 17
2 h 10 min 17 - 21 ALT CRZ * HDG
2 h 10 min 21 - 26
2 h 10 min 26 - 36 V/S +6000 HDG
2 h 10 min 36 - 42
2 h 10 min 42 - 43 V/S +1400 HDG
2 h 10 min 43 - 47
2 h 10 min 47 - 2 h 11 min 40 V/S +1400 HDG
2 h 11 min 40 - 2 h 12 min 52
2 h 12 min 52 - 2 h 12 min 58 V/S +1400 HDG
2 h 12 min 58 - 2 h 13 min 57
2 h 13 min 57 - 2 h 13 min 58 Not recorded- period of associated
parameter sampling insufficient
2 h 13 min 58 s - end of flight
See Page 95 Final report.

Page 198 Conclusions:
"The Flight Directors did not disconnect.
The crossbars disappeared and then re-appeared on several occasions, changing mode several times."

mm43 8th Nov 2012 18:03

The previous few posts have highlighted IMO the single minded focus the PF had in over-controlling the roll (PIO) at the expense of paying any attention to pitch attitude, vertical speed or altitude. At the back of his mind was his initial introduction to all the good things associated with Airbus FBW, i.e.

In Normal Law it is a protected aircraft with three thresholds incorporated in the protection:
  • Alpha Prot(ection), which is the maximum attainable stick-free AOA. The auto-trim stops there because there is no valid reason to fly at such a low speed for a lengthy period of time; the speed brakes, if extended, retract automatically.
  • Alpha floor, which is the AOA where engine thrust increases to TOGA even with auto-thrust selected off.
  • Alpha max, which is the maximum attainable AOA with the side stick held fully back.
It took 18 odd seconds for the PNF to announce (I suspect rather quietly), "ALT LAW, protections lost". During that time the PF had just assumed that provided he kept the SS back, the longitudinal stuff would look after itself. It didn't, and with less than 50 seconds of the flight remaining, his hallelujah announcement, "But I’ve been at maxi nose-up for a while", kind of says it all.

None of the above excuses the lack of CRM or lack of reference to the QRH, when it was patently obvious that they knew they "had lost the speeds".

HazelNuts39 8th Nov 2012 19:32

Just another question that occurred to me, to long-range wide-body pilots in particular:

Shortly before A/P disconnect, the CVR recorded this exchange:

2 h 07 min 01 (PF): See, we’re really on the edge of the layer (and under the squall)
2 h 07 min 05 (PF): I mean I’m sure that with three six zero no standard would be good, we’d be ok eh (j’veux dire je suis sûr qu’avec un trois six zéro non standard on serait bon, on serait pas mal hein)
2 h 08 min 03 (PNF): Don’t you maybe want to go to the left a bit?

At about 2 h 10 min 26 the airplane was climbing through FL360.

Could the PF have been looking outside and, aquiring some visual references, attempted to fly by those?

Lyman 8th Nov 2012 19:51

mm43, hiya....

I think that "50 seconds of the flight remaining, his hallelujah announcement, "But I’ve been at maxi nose-up for a while", kind of says it all."

Was a directed response to a request (urgent?) to climb. As such, PF tips his mind set, and it is damning. He is unwittingly saying that keeping the stick full back has not resulted in....a climb. Which means that he thinks it should, though obviously it has NOT. It also (parenthetically) shows us that all three, AT THIS POINT, do not know what is happening. Sorry, they know WHAT, they do not know HOW.

HazelNuts39

Are there any widebody Captains still here? Because I am tempted to ask who in the world would fly visual here? Aren't they discussing Radar returns?

HazelNuts39 8th Nov 2012 20:34

Lyman,


He is unwittingly saying that keeping the stick full back has not resulted in....a climb. Which means that he thinks it should, though obviously it has NOT.
Good analysis!:ok:

mm43 8th Nov 2012 20:48

HN39; Lyman;

I agree with that "good analysis".

It doesn't quite explain why keeping the SS back on approach to the stall with SW echoing in his ears, seems to have worked for him.:\

A lesson quickly learned and acted upon again when the SW returned - but in NCD mode.:eek:

Andy24 30th Dec 2012 09:10

Simulating this in simulator ( PPC additional training)
 
As part of my airline's recurrent simulator training, we have been asked to simulate the Air France incident. In order to practice the 'Startle Effect' (and in order to avoid the pilots knowing what is going to happen next)it has been left to the discretion of the instructor on how to simulate this in the sim.

I have some ideas in mind ( Volcanic ash encounter and blocked pitos)however would appreciate any feedback from fellow TRI's.

Lyman 30th Dec 2012 16:16

mm43

"It doesn't quite explain why keeping the SS back on approach to the stall with SW echoing in his ears, seems to have worked for him."

And it cannot, because he is unaware of his altitude. He cannot have been, given the discussion just prior re: temps. It is ironic how the conclusions are in, and present the fantastic as normal, and reality as bizarre..... It is in the nature of directed thought and propaganda, however....

May we hear the CVR?

Thought not. Although one hopes the complete data will be provided to NTSB and FAA. If it is, it will be demanded via FOIA....

Patience.

DozyWannabe 30th Dec 2012 17:48


Originally Posted by Andy24 (Post 7602214)
I have some ideas in mind ( Volcanic ash encounter and blocked pitos)however would appreciate any feedback from fellow TRI's.

Technically speaking, the TRE in our sim experiments simply failed 2 ADRs in turbulent conditions and triggered a brief thrust asymmetry to simulate the initial roll. The narrative aspect will likely be at the TRE's discretion.

RR_NDB 1st Jan 2013 18:29

CVR
 
Bear,

May we hear the CVR?

:mad:

roulishollandais 2nd Jan 2013 02:09

@Andy24
Is it possible to get a little more about your experience?
Which UAS procedure have you used, How much initial pitch did you use, Did you simulate the LOC? Which airline? Which Sim?
Thanks

PJ2 2nd Jan 2013 06:39

HN39;

Re, "Could the PF have been looking outside and, aquiring some visual references, attempted to fly by those?",

Almost certainly no, he's not flying or attempting to fly clear of cloud by means of visual references. Reasons: a) instruments, not visual cues would be the primary guidance; b) too dark, (no moon) to see the tops, c) even with a moon it is very difficult to judge height of cloud in front...it would be by chance that cloud would be avoided, d) it's just never done, (as in, it is not considered a viable, legitimate manoeuvre nor is it trained); e) change of altitude or track is never done without an ATC clearance. The pilot-in-command of an aircraft an deviate from an ATC clearance in an emergency where the safety of the flight is at immediate and clear risk. As you know, it is my opinion that the loss of airspeed information and the degradation to manual flight is not an emergency.

Lyman;

"Aren't they discussing Radar returns?"

Yes, almost certainly that is what is being discussed. The conversation I "hear" is just what I would have heard in my own cockpit...very ordinary, very operational...normal.

It is extremely rare that the actual CVR is released. Not even the FOIA will do this.

Usually it is notions like "the public interest" that would cause a consideration to do so and even then it would be heavily restricted and "in-camera" in the court so ruling with only the participants absolutely required by the process.

alogobotur 20th Feb 2013 14:49

Hello to all of you, I need one info.

Does anybody have the AF447 book by J.P.Otelli?

If yes, can you tell me is there an english edition or just in French?

Thank you.

roulishollandais 21st Feb 2013 14:55

BEA report is better in any case

Lonewolf_50 21st Feb 2013 15:00

Lyman:

Can we agree that loss of SA may have at least potentially involved spatial disorientation?
Maybe. It depends on what you mean by spatial disorientation.

You can have spatial disorientation without any "feel induced" disorientation playing a part, a common affliction in a non-motion simulators. It isn't hard to wind up massively spatially disoriented (where you are in the air and what you are doing versus where you think you are in the air and what you are doing) by having a lousy instrument scan and a bit of a ham fist. I offer myself and my first few instrument navigation sims during flight training as Exhibit A. I think the term "utterly fargin' lost" (or words to that effect) crossed my sim instructors lips at least once. Weak/poor instrument scan and possibly rough hands look to have been part of this crew's problem.

Back to your question.

I suggest that between time zero and time five seconds of this event (pitot data deemed bad and all three rejected by aircraft systems) SA itself was partial to begin with.

Spatial disorientation loss, or at least impairment, need not have been in the "feel" domain at all. Over the past years on this topic, it has been my estimation that an initial "scan impairment" was exacerbated by the mental effort being expended upon "what's it doing now," which takes you back to some fundamental systems knowldege and training issues, CRM and systems trouble shooting methods. Won't repeat them here.

Based on what can be put together after the fact by looking at the record of outcomes (pilot actions with controls and aircraft performance), the degree of SA retained remained at best partial
-- one cue being as you mentioned, rate of descent and the attendant cue of decreasing numbers on the altimeter seem not to have registered --
and I'll even assert that SA decreased as the time moved forward from zero to impact.

In shorter terms, the crew started behind the aircraft, and got further behind as the event progressed.

This in turn leads me back to both upset and "out of control flight." Out of control flight is more or less the situation in which you make certain inputs to the controls, expecting response A, but you get response B (or perhaps no response at all).

You don't have to be stalled to be out of control.

In one fixed wing aircraft I am familiar with, you can be in a spiral (high roll rate/rotation descent) with symptoms similar to but not the same as a spin (which begins in a stall and gyrates as the plane falls).

If you make control input A, anti-spin control inputs, what you won't get is a recovery from a spin (nor the actual spiral) since you aren't stalled in the first place. What you'll get is response B which is that the plane stays in the spiral until you either hit the ground or you figure out what is actually happening and put in control input B, which would be recovery from a spiral and then fly away.

Until you recoginze what the plane is doing (Situational Awareness at its most basic) your inputs may not yield the outcome you expect, nor the one you desire.

Because the flying pilot believed that the plane was still flying (SW noise and other inputs notwithstanding), he made contol input A, kept making control input A even after a few responses to his crew mate on him going up, and he kept getting response B.

The "aha moment" of "we are stalled" never arrived.

SA was never achieved in any meaningful way beyong the pilot not flying
-- observing that the protections had been lost
-- offering corrections to PF in re "stop going up" that are taken form the CVR.

Because this was a crew, I have to assess the SA of the CREW, as well as individual SA of each pilot who made up the crew.

The sum of their SA was most certainly NOT greater than the two parts. :( The outputs don't suggest either got vertigo, but "disorientation" in terms not "seeing" what their primary flight instruments were showing them is a rather obvious post mortem finding.

Respectfully asserted to those involved in the discussion at this point:
IMO, somatogravatic illusion is a red herring in this particular case.


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