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AF 447 Thread No. 11

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AF 447 Thread No. 11

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Old 1st Dec 2013, 12:33
  #961 (permalink)  
 
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Hi Winnerhofer,

Thanks for your link to the "full" Transcription CVR from the Rapport d'Expertise of 2012 (sometimes referred to as the judicial report), and the Conclusions.

It fills in some of the "(...)"s in the transcript pubished in Appendix 1 of the BEA Final Report, and there are some split-second variations in timing. However, I've yet to find any evidence of supernumerary presence in the cockpit, which you claimed a few days ago?

Re your latest post, quote:
e) As a system, the A330 is not tolerant to single failure of the Pitot probes, which is contrary to all the rules of reliability and dependability . For an event of this severity (catastrophic , in the sense of the term dependability , i.e. which can cause victims), the system must be fail-safe design (it must guarantee the safety of the flight despite the failure ), and even FS / FS that is tolerant to double down.

I've never been involved in engineering or standards of certification, but venture to suggest that, as a system, the A330 and its crew is indeed tolerant to a failure of all 3 airspeed probes, provided the crew acts in a manner that might be expected of one which is properly qualified in terms of training and experience. Having said that, it is clear that the training, SOPs and the UAS drills/checklist left much to be desired.

Quote:
Namely redundancy probes (actually 3 ) is false redundancy since all the sensors are the same technology therefore likely to fail at the same time , under the effect of a single common cause .. . icing.

Yes, and this is not peculiar to Airbus, When we discussed this a couple of years ago on an AF447 thread, I commented that it had sometimes crossed my mind - during external checks on various a/c, incuding Airbuses - that the policy of mounting pitot probes and AoA probes symmetrically left and right invites the coincidence in timing of any icing problems. This tends to pertain to the #1 & #2 probes, with the #3 being asymmetric to them. One can understand the traditional philosophy of similarity of the two primary detectors, but it will be interesting to see if AF447 leads to a rethink at least in terms of the siting of probes, if not dissimilar specifications of the probes (and/or probe-heaters) themselves.

Last edited by Chris Scott; 1st Dec 2013 at 13:48. Reason: Spelling. 2nd para extended.
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Old 1st Dec 2013, 15:16
  #962 (permalink)  
 
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(Re)Marks: (reference: post #974)

Air France :
a) I cannot comment; if true, I (sadly) won't be entirely suprised. Let's say 1.
b) Wrong; AF asked; to say "not with enough emphasis" is hindsight. 0.
c) How is this relevant? Doesn't BUSS work @ lower than FL250 only? No one can tell a BUSS-equipped A330 would have met a different ending, this night. 0.
d) It may have been better worded (and was, since). But it was not inappropriate. 0.25 for the ink.
e) Agreed. Regarding stall recovery, it was not AF, it was industry-wide. 0.75.

Total: 2/5. Case lost IMO.

Airbus :
a) Wrong. First event in the chain does not equal to root cause. 0.
b) Wrong. Their fault didn't generate (in the sense of being responsible of). 0.
c) I cannot comment; if true, I (sadly) won't be entirely suprised. Let's say 1.
d) Is same than C. No point.
e) Wrong. 0.

Total: 1/5 (because I have no argument against/for this unique point). Case lost IMO.

It should be added that Airbus and Air France have deep pockets, and sprinkle a few coefficients on all this for a chance to win the day.

OTOH, thanks for you last links, will read that with attention a bit later
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Old 1st Dec 2013, 16:45
  #963 (permalink)  
 
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Dubois S/S

00:31:16 CDB: J'aime bien sentir la marche
(I like to feel the step)


This bit has been overlooked.
What he did was it that he yanked the S/S which which resulted in NU movement of the THS as shown on the DFDR.





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Old 1st Dec 2013, 16:58
  #964 (permalink)  
 
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Chris Scott;

Re, "However, I've yet to find any evidence of supernumerary presence in the cockpit, which you [Winnerhofer] claimed a few days ago?"

In the CVR record, there are some communications with the F/As. Such communications are routine and usually concern meals, anticipated turbulence, route information, passenger matters, etc. It would not be uncommon for an FA to be on the flight deck for a few moments for such communications. Many times such communications are done through the cockpit-cabin interphone system but of course the meals are always brought into the cockpit and inevitably a short chat takes place. Normal operations, (meal service, discussions regarding turbulence, etc) would not be "evidence of supernumerary presence".

It may be different in Europe, the US etc, (although I doubt it), but regarding ETOPS qualifications, pilots are trained and qualified for such operations but ETOPS is not an endorsement on the licence. Just as one is not "endorsed" for Category III operations, one is trained and qualified for such operations on the airplane one is operating. Such training and qualifications would normally only be part of the pilot's current qualification file and are not on the actual pilot's licence.

For the record regarding comments made elsewhere in re SW111, last time I looked, the MD11 was a 3-engine aircraft and ETOPS stands for "Extended-range Twin-engine Operational Performance Standards" and the TSB made no such comments regarding crew ETOPS qualifications.

Last edited by DonH; 1st Dec 2013 at 17:34.
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Old 1st Dec 2013, 18:26
  #965 (permalink)  
 
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Hello Don,

Yes, the only exchanges I've seen so far fall into the category of short exchanges with flight-attendants in the two ways you describe. Pity that the CVR transcript does not distinguish between the different audio channels, i.e.: output from area microphone, inputs to pilots headphones, and output from pilots' headset-microphones.

BTW, do we yet know if the pilots' headset-microphones on the A330 in AF are permanently "hot", as on all British a/c (IIRC)?
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Old 1st Dec 2013, 19:33
  #966 (permalink)  
 
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On the transcript, does the red sideline mean the stall warning is active and audible?
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Old 1st Dec 2013, 19:33
  #967 (permalink)  
 
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AF447: Ménage à Trop

AF447: Ménage à Trop - AF447
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Old 1st Dec 2013, 19:44
  #968 (permalink)  
 
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Hi Chris;

I believe all A330 mikes (4 - two forward seats, two observer seats) are hot by design which I expect would include cabin interphone communications, (handset on the rear of the pedestal). It's reasonable to assume that the cockpit mike picked up pilot-FA communications in the cockpit.

From an earlier post, above, "There were already signs of this impending problem 20 years ago, and it is not restricted to FBW Airbuses.", yes indeed there were. In fact AW&ST ran a series of articles on automation in August of 1989 and in late January and early February of 1995. The problem was seen and being understood from the earliest days.

A discussion of why the problem not only continued to grow in breadth but also in depth, (ie., it got worse) is beyond the present thread's context and "charter" so to speak and each of us will have our own theories that I'll just touch on.

The trend itself was, and remains clear, however. I agree with come posters here who say that more manual flight training may not be the answer, although psycho-motor skills do need constant reinforcement to build muscle memory that can be quickly relied upon when rational thought and analysis can take more time.

To me it is separation of the cockpit from flying the machine that is the model for the separation of the vastly different human psychological-physical acts of button-pushing (which is "on-the-surface" cognitive activity, from arms-legs control movement, which (I would offer) is more on the autonomic side of human muscular activity. One no longer straps the airplane on so to speak, one sits "in" it and manages it and is placed psychologically "outside" of the machine.

We're not digital creatures and although we quickly adapt, there is what I used to call a "digital veil" between pilots and the machine that wasn't there in, say, the DC8 (or, I would hazard a guess, the VC10). I don't think the human factors which have evolved out of the past 20 years, of which this accident is but one example, have been examined nearly deeply enough - perhaps that is for all those safety conferences held around the world but I would like to have seen more from the BEA in this regard.

That said, I think automation is a far safer way to fly transports and given the numbers, crews have adapted to automation, "mode Normal", admirably.

But I can attest having experienced it, when it fails and the airplane (A330) is in the process of degrading itself to its next level of control as it adjusts to a system failure, it can be momentarily, very busy. One just has to let it do its thing and settle down.

As with the loss of airspeed information, generally one does not have to act swiftly, automatically but slowly carry out the Abnormal SOPs as has been amply described in these threads.

Anyway, enough drift.
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Old 1st Dec 2013, 21:10
  #969 (permalink)  
 
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On the transcript, does the red sideline mean the stall warning is active and audible?
The legend is in the top right corner of page 10 of the DFDR document.
The red sideline indicates the stall warning is active and (presumably) heard on the tape. When the stall warning is not active, the C chord is active almost the entire remaining time (stall warning not active) except for a brief interval just after the Captain entered the flight deck when they transitioned the correct FL.

My thanks to HN39 for straightening out my misconception about the signals being interleaved. Stall warning has absolute priority while active.
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Old 1st Dec 2013, 21:17
  #970 (permalink)  
 
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Machinbird, yes that is how I took it to be read. But what about all the 'stall inhibited' discussion and the discussion that the Cpt didn't have a chance to hear it other than 1 sec after he returned ? Also, a lot of dual input tussles: almost a continuous 'fight'.
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Old 1st Dec 2013, 22:12
  #971 (permalink)  
 
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Mr. Optimistic;

Re, "Also, a lot of dual input tussles: almost a continuous 'fight'. "

Yes, as we know from the threads, dual inputs are absolutely verboten in the Airbus. You either take control or leave it alone. If someone is doing something leading to an accident, one takes the airplane, and sorts it out on the ground later. The trouble is, the PF continuously interferred with what the PNF sensed and wanted to do and they failed to sort it out. Courtesy, arguing and timidness won out over training, SOPs, CRM and ultimately, survival in this accident.
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Old 2nd Dec 2013, 00:02
  #972 (permalink)  
 
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AF447: A Disaster Foretold

AF447: A Disaster Foretold - AF447
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Old 2nd Dec 2013, 00:12
  #973 (permalink)  
 
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BEA Annotations

All BEA annotations:

RAPPORT FINAL-050712-ARH.pdf
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Old 2nd Dec 2013, 00:19
  #974 (permalink)  
 
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Quote from DonH (my emphasis):
I agree with come posters here who say that more manual flight training may not be the answer, although psycho-motor skills do need constant reinforcement to build muscle memory that can be quickly relied upon when rational thought and analysis can take more time.

There are certainly no easy solutions to the problem, which we and others recognize. However, in the many UAS events covered in the BEA AF447 reports, the PFs have had no alternative than to take manual control at short notice. Whether that sudden and unexpected transition initially involves action or inaction on the side-stick, it is going to be far less challenging mentally and physically if the PF has had fairly recent experience of hand-flying the a/c (also in C* law in this case) without FD in similar conditions, albeit with the advantage of an ASI.

Evidence suggests that the PF of AF447 tensed up, pulling the stick back inadvertently as he concentrated on controlling roll in roll-direct law. That would imply a lack of confidence in his ability simply to fly the a/c straight and level. Confidence, IMO, is enhanced by practice. Lack of confidence exacerbates the initial startle factor.

I've already covered the issue of familiarity with the effect of small changes of pitch attitude in recent posts. As we have seen on this thread, it is not only UAS that can lead to pilots losing control when the AP disengages at altitude.
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Old 2nd Dec 2013, 07:08
  #975 (permalink)  
 
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CRM

Psychometrics
Bonin was exempted.
30 AF F/As were fast-tracked in 2008 onto the LH-seat.
Psychometric testing eliminates 70% of candidates.
Robert
Indeed, he was the odd-man out and the least incompetent.
He was alone i.e. w/o spouse or companion.
Yes, inhibitions based on courtesy meant that Robert and Dubois had no effective authority over Bonin.
Dubois was in an other World and plagued by strife on the home front.
The social interraction of the crew overruled CRM.
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Old 2nd Dec 2013, 08:50
  #976 (permalink)  
 
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Experts II

Quote:

Airbus l'a formellement contestée et des experts internationnaux seront nommés notammanet un Professeur suisse.
Elle est bourrée d'erreurs et de raisonnement qui ne tiennent pas la route
.

Airbus has formally contested the findings of the Experts and new international panel consisting of non-French members have been appointed notably a Swiss Professor.
The Experts report is riddled with errors and reasoning that doesn't hold water.

The technical bit that Airbus has a bone about is that the report confuses AOA and pitch.

Now let de battle commence!

Last edited by Winnerhofer; 2nd Dec 2013 at 09:03.
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Old 2nd Dec 2013, 09:32
  #977 (permalink)  
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Thread #12 starts here
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