AF 447 Thread No. 12

[Winnerhofer]

Thread part -

This thread series started out of an earlier thread which starts here (http://www.pprune.org/tech-log/376433-af447.html#post4974708) and finishes here (http://www.pprune.org/tech-log/376433-af447-229.html).

Another, slower moving, thread on the subject and covering the period from the original thread, above, and the start of thread #4


#1 starts here (http://www.pprune.org/tech-log/395105-af-447-search-resume.html#post5303737) and finishes here (http://www.pprune.org/tech-log/395105-af-447-search-resume-195.html#post6408432).
#2 starts here (http://www.pprune.org/tech-log/449639-af-447-search-resume-part2.html#post6408428) and finishes here (http://www.pprune.org/tech-log/449639-af-447-search-resume-part2-127.html#post6476460).
#3 starts here (http://www.pprune.org/tech-log/452836-af447-thread-no-3-a.html#post6476336) and finishes here (http://www.pprune.org/tech-log/452836-af447-thread-no-3-a-104.html#post6515428).
#4 starts here (http://www.pprune.org/tech-log/454653-af-447-thread-no-4-a.html#post6515515) and finishes here (http://www.pprune.org/tech-log/454653-af-447-thread-no-4-a-54.html).
#5 starts here (http://www.pprune.org/tech-log/456874-af-447-thread-no-5-a.html#post6561270) and finishes here (http://www.pprune.org/tech-log/456874-af-447-thread-no-5-a-100.html).
#6 starts here (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a.html) and finishes here (http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-85.html#post6793822).
#7 starts here (http://www.pprune.org/tech-log/468394-af-447-thread-no-7-a.html) and finishes here (http://www.pprune.org/tech-log/468394-af-447-thread-no-7-a-68.html).
#8 starts here (http://www.pprune.org/tech-log/482356-af-447-thread-no-8-a.html#post7129212) and finishes here (http://www.pprune.org/tech-log/482356-af-447-thread-no-8-a-78.html#post7278807).
#9 starts here (http://www.pprune.org/tech-log/489774-af-447-thread-no-9-a.html#post7278812) and finishes here (http://www.pprune.org/tech-log/489774-af-447-thread-no-9-a-74.html#post7370230).
#10 starts here (http://www.pprune.org/tech-log/493472-af-447-thread-no-10-a.html#post7370219) and finishes here (http://www.pprune.org/tech-log/493472-af-447-thread-no-10-a-54.html#post7759937).
#11 starts here (http://www.pprune.org/tech-log/511119-af-447-thread-no-11-a.html#post7760634) and finishes here (http://www.pprune.org/tech-log/511119-af-447-thread-no-11-a-49.html#post8183878)

Total posts to date 17634 .. with in excess of 2.7 million views overall.

Links to the various BEA reports are given below. If I have missed any of the useful papers, please PM me with the URL and I can include it.

(a) BEA site - French (http://www.bea.aero/fr/index.php), English (http://www.bea.aero/en/index.php)
- Report link page - French (http://www.bea.aero/fr/enquetes/vol.af.447/vol.af.447.php), English (http://www.bea.aero/en/enquetes/flight.af.447/flight.af.447.php)

(b) Interim Report (No, 1) Jul 2, 2009 - English (http://www.bea.aero/docspa/2009/f-cp090601e1.en/pdf/f-cp090601e1.en.pdf)

(c) Interim Report No. 2 Dec 17, 2009 - English (http://www.bea.aero/docspa/2009/f-cp090601e2.en/pdf/f-cp090601e2.en.pdf)
- Update Dec 17, 2009 - French (http://www.bea.aero/fr/enquetes/vol.af.447/point.enquete.af447.17.12.2009.pdf), English (http://www.bea.aero/fr/enquetes/vol.af.447/update.on.the.investigation.af447.17.12.2009.en.pdf)

(d) Estimating the wreckage location Jun 30, 2010 (http://www.bea.aero/en/enquetes/flight.af.447/phase3.search.zone.determination.working.group.report.pdf)

(e) Wreckage search analysis Jan 20, 2011 (http://www.bea.aero/fr/enquetes/vol.af.447/metron.search.analysis.pdf)

(f) Briefing and associated update May 27, 2011
- Briefing (http://www.bea.aero/fr/enquetes/vol.af.447/info27mai2011.fr.php) - update French (http://www.bea.aero/fr/enquetes/vol.af.447/point.enquete.af447.27mai2011.fr.pdf)
- Briefing (http://www.bea.aero/fr/enquetes/vol.af.447/info27mai2011.en.php) - update English (http://www.bea.aero/fr/enquetes/vol.af.447/point.enquete.af447.27mai2011.en.pdf)
- Briefing (http://www.bea.aero/fr/enquetes/vol.af.447/info27mai2011.de.php) - update German (http://www.bea.aero/fr/enquetes/vol.af.447/point.enquete.af447.27mai2011.de.pdf)
- Briefing (http://www.bea.aero/fr/enquetes/vol.af.447/info27mai2011.br.php) - update Portugese (http://www.bea.aero/fr/enquetes/vol.af.447/point.enquete.af447.27mai2011.br.pdf)

(g) Interim Report No. 3 July 2011 - French (http://www.bea.aero/docspa/2009/f-cp090601e3/pdf/f-cp090601e3.pdf), English (http://www.bea.aero/docspa/2009/f-cp090601e3.en/pdf/f-cp090601e3.en.pdf)

(h) Links to final report Jul 5, 2012 and associated documents. (http://www.bea.aero/en/enquetes/flight.af.447/rapport.final.en.php)

Miscellaneous pertinent links -

(a) Airbus Operations Golden Rules (http://www.airbus.com/fileadmin/media_gallery/files/safety_library_items/AirbusSafetyLib_-FLT_OPS-SOP-SEQ03.pdf)
(b) ALPA FBW Primer (http://cf.alpa.org/internet/alp/2000/febfbw.htm)
(c) C* and Civil Transports - Cranfield (https://dspace.lib.cranfield.ac.uk/bitstream/1826/186/2/coareport9303.pdf)
(d) Longitudinal Flight Control Design - RAeS (http://www.raes.org.uk/pdfs/2989.pdf)
(e) Longitudinal Stability: Effect of High Altitude and CG - Boeing (http://boeing.com/commercial/aeromagazine/aero_02/textonly/fo01txt.html)
(f) pitot static system performance - USN (Pax River) FTM (http://www.aviation.org.uk/docs/flighttest.navair.navy.milunrestricted-FTM108/c2.pdf)
(g) The Problem of Automation: Inappropriate Feedback and Interaction, Not Over-Automation. Donald A. Norman UCSD (http://www.jnd.org/dn.mss/Norman-overautomation.pdf)
(h) Upset Recovery - 16MB zip file (http://www.mediafire.com/?jrkvp2ysl7aea25)
(i) Ironies of Automation. Lisanne Bainbridge UCL (http://www.bainbrdg.demon.co.uk/Papers/Ironies.html)
(j) Cognitive Capability of Humans. Christopher Wickens Uni Illinois (http://www.humanfactors.uiuc.edu/Reports&PapersPDFs/chapters/Wickens_Durso%20Aviation.PDF)
(k) Trust in Automation: Designing for Appropriate Reliance John D. Lee, Katrina A. See; Human Factors, Vol. 46, 2004 (http://www.questia.com/googleScholar.qst;jsessionid=LHmZGvvpc1T1RT2pThDgGpvfwpMvh6f TTBPVC4hD8Tpg8J4LdQZy!-290722064?docId=5008765429)
(l) Training for New Technology. John Bent - Cathay Neil Krey's CRM site (http://www.crm-devel.org/resources/paper/bent.htm)


Search hint: You can search PPRuNe threads with a filter in Google by using the following search string example -

ths af447 site:http://www.pprune.org/tech-log/ (http://www.pprune.org/tech-log/)

This will search for mentions of THS in the AF447 threads of tech log only.

Just change the THS in the string to whatever you want to look for. This allows one to search for any term or phrase of interest throughout the threads.

Adding the site:URL end part is the magic that restricts Google to only searching in Tech Log.

This filter technique is absolutely wonderful and can be used generically to find things of interest in PPRuNe - appears to work OK in the PPRuNe search function as well.

In respect of Google searching, JenCluse has added some suggestions -

a) indenting the text block with a (one) Tab, *and*

b) emphasizing the fact that it is a search text block with some manner of . . .
< SearchText>, or
"SearchText"

Another search engine approach tailored for AF447 can be found here (http://countjustonce.com/pprune/).

NB This thread has been merged into the main AF 447 saga as thread No 12. Originally, I expected it not to develop a life of its own .. but I was grossly wrong ... isn't the first time and certainly won't be the last ... c'est la vie ... I'll tidy up the detail in this post over a coffee tomorrow .. JT

[F-16GUY]

Any expert panel who says that the pilots are to blame, without looking into what and how the company behind acted to put the pilots in that position/situation, does not know anything about flight safety and aviation safety culture.

But hey, if everybody is happy when the dead pilots are blamed, then lets not learn anything from this and move on to the next event that will look more or less like this one.:ugh:

[DozyWannabe]

That's an oversimplification of the article. What it says is (pardon Google Translate):

The first three relate to the crew, they cite "lack of structured failure analysis" , "not understanding the situation" and "the division of labor in the cockpit that has not been applied rigorous " . But they also involve the airline, deploring a "lack of clear direction from Air France despite several similar cases after the icing of the pitot probes and thus a return to insufficient experience" .

They point also "inadequate pilot training in the application of the Unreliable IAS procedure" , required when probes have iced over, and the behavior of the aircraft during the loss of speed indications. They also mention the stress and fatigue of the crew, "the questionable attitude of the captain leaving the cockpit despite the questions asked by the first officer" .

So saying the panel "blames the crew" and leaves it at that is inaccurate. The airline comes in for censure, and the aircraft's behaviour is earmarked for review. This is all old news though, as this does not diverge significantly from the findings of the final report.

I note the "relatives" (read : SNPL) lawyer has been quoted as though the report and panel do blame the crew - but that's pretty much par for the course.

[alf5071h]

Winnerhofer, it appears that you are the one allocating blame.

My rough translation identifies the following significant aspects (as DW):-
“Inappropriate response of the crew”,
“Lack of structured failure analysis",
“Not understanding the situation"
“The division of labor in the cockpit."
“Inadequate pilot training in the application of the procedure unreliable IAS."

Modern views of human behavior do not allocate blame; instead they look for underlying contributions such as an inappropriate response which often results from a failure to understand the situation (awareness and training) and selection or application of procedures (training and reliance on humans to manage complex situations).
The report also considers the underlying technical failure and infers (my view) that the operational / regulatory approvals to continue based on refresher training also contributed.

[DutchOne]

Initially it was a technical malfunction. What led to a situation where proper pilot reaction was needed. This was not given. And to be honest the reaction needed was very basic and easy, but still not given. This is considered pilot error and you can not deny that pilots are not to blame at all. BUT not proper training and human factors are definitly important causations.


It is quite obvious why the outcome of both reports are so different. one was done by BEA (frensh authority for safety). For them it is important that people keep on flying AIR FRANCE. The other is done on request by airbus. Need more to say!!!


One thing is indeed really worrying:
(As Winnerhofer said:) And do not forget that we had a BEA report w
ith recommendations for aviation safety. These recommendations have unfortunately not been implemented: it's really dramatic, we must address this problem.

[roulishollandais]

Does anybody know the Air France A330 IAS and UAS procedures today 16.May 2014 ?

[DozyWannabe]

It is quite obvious why the outcome of both reports are so different. one was done by BEA (frensh authority for safety). For them it is important that people keep on flying AIR FRANCE. The other is done on request by airbus. Need more to say!!!

With respect, I don't think the BEA are particularly bothered one way or another regarding AF's business fortunes - their remit is to investigate accidents and incidents, usually to French-registered aircraft, and make recommendations to prevent them from happening again. Same with Airbus - they don't want their aircraft to have continuing issues.

All the old "cover-up" rubbish is just that - complete rubbish.

[john_tullamarine]

.. and, should the thread descend into witch hunts and conspiracy circular thoughts .. it will be despatched to a more appropriate forum ...

[Derfred]

It is clear that both the Pilot Flying and the Pilot Not Flying were completely out of their depth in interpreting and correcting the situation.

The big question is, is that typical of Air France pilots (in which case the Airline and/or regulator is primarily to blame), or was it an aberration?

Were Air France pilots properly trained to set attitude and thrust when faced with an airspeed issue?

If not, are they now?

[alexd10]

As a colleague of mine use to say , in this field the improvements are often written in blood. Maybe it is worth to try here to review what changes was eventually written in the blood of AF447 228 souls.. (industrywide!) . Certainly many of the posters and followers of this forum are interested, and after all it is muchmore important for the industry than “witch hunts and conspiracy circularthoughts” .

In the immediate aftermath of disaster there were of coursechanges in training programs, an AD that imposed the change of pitots, even a change of the the UAS procedure and more .. And later there were perhaps other, introduced more orless quietly.
For example in 5 years it was time for more software updates, butdoes someone know whether Airbus did changed the marvelous pieces of logicwhich allowed FD to step in by itself in a changed mode after a clear condition of “FD- off; AP - off”, or the THS to run to thenose-up limit in the same time with SW, or SW to be disabled in a full stalledplane, at FL >100, with a full working AOA vane?
And such other maybe... - things surfaced in this tragedy and and that would be a shame for the industry to remain unchanged…

[jcjeant]

.. and, should the thread descend into witch hunts and conspiracy circular thoughts .. it will be despatched to a more appropriate forum ...

And in what forum?
I do not see in PPRuNe a forum section dedicated to the policy
Because it comes well political watered with some economic drops
BEA depends administratively on the French Ministry of Transport
The French state is a shareholder in Air France
Conclusion? conflict of interest ... simple as that :)

[DaveReidUK]

Does anyone know how many of the senior management of Air France, the BEA, Airbus and the DGAC went to the same Grandes Ecoles ... ?

[Chris Scott]

IMHO, the only crumb of comfort to be drawn from this otherwise unmitigated tragedy is that every thinking student and practitioner of aeronautics has found something to learn from it. I imagine that may also apply to those concerned with deep-sea search operations.

However, one might have expected the BEA recommendations on flight-recorder ULBs to have been addressed, amended (if necessary), and implemented in time for MH370.

[Mac the Knife]

The mystery to me is why the the PF and PNF did not action the UAS (or any other) procedures on AP dropout.

With no SA whatsoever they pulled up into a stall, lost the plot comprehensively and fell into the sea.

It is hard to understand, and I still haven't seen any kind of explanation that makes sense.

:(

[Chris Scott]

Mac,

Notwithstanding the inexplicable mishandling by the PF, the bigger mystery for me has always been the apparently deferential attitude of the older, more-experienced PNF, who seemed to decide that the only person who could rectify the situation was the absent captain.

[Mac the Knife]

Chris, d'ye know I've seen suchlike in the operating theatre on occasion.

A forceful and confident junior leading a mild and unassertive senior into dangerous situations out of the capabilities of both.

'Tis a question of personalities.

(and yes, I've sometimes been the old guy roused out of his bunk to try and fix things - the first step is to establish your absolute authority and take over completely)

[Chris Scott]

" 'Tis a question of personalities."

Quite. AF447 is all about human factors, and in this case they are not confined to the cockpit - or the aeroplane on the night.

However, a captain called from his/her bunk has to be wary of premature takeover...

[alf5071h]

“…why the PF and PNF did not action the UAS…”
Perhaps they did, except that it was the memory drill required for after takeoff – nose up (15 deg?), as opposed to the more benign level flight case on the same page.
This action might have been influenced by an inappropriate emphasis on this part of drill during the mandated UAS refresher training; also this might identify a difference between the accident and other successfully recovered incidents, apart from many other human behaviours.

“…the apparently deferential attitude of the older, more-experienced PNF…”
Perhaps he too was struggling to understand the situation, and with rapidly evolving circumstances was mentally limited, including time dilation, which delayed alerting the Captain.

The lessons to be learnt from this accident are in the successful recoveries of previous events. Everyone is trying to find a cause and thus something to irradiate, yet if we can understand what previous crews did with success and incorporate/strengthen that in operations then perhaps we might avoid similar situations.

W.r.t. the many French agencies, I have worked with most of them during certification and safety-incident investigation. My experiences were of very dedicated, knowledgeable, impartial, and independent organisations and individuals, whose primary aim was safety.
In recent years investigative authorities tend to invite the aircraft and vendor manufacturers to take a much more active role in investigations as it is apparent that no one group can have a sufficiently deep understanding of systems design and operation.

[Porker1]

Is it possible that the PNF had less visual feedback on what the PF was actually doing due to the little Airbus sidesticks rather than traditional joysticks? Surely for any pilot the sight of the PF hauling desperately back on the stick ad infinitum would have maybe aided in his diagnosis of the problem (not withstanding the immediate resounding of the stall alarm the one time that the PF stopped pulling back)?

From what I've read I don't think that they're wrong to blame the PF as his initial reaction to the cacaphony of alarms was all wrong given the situation. However, AF failed on the implementation of pitot tube technical diversity despite previous warning incidents, adequacy of their pilot training can be put in question, and some the Airbus alarms and systems really didn't help in the correction of the initial error.

[roulishollandais]

Let ze battle commence!Same schools or not, Air France is saying that Judicial Airbus Counter Experts did not search Air France arguments. In consequence AF is asking annulation of that Airbus counter expertise on judicial procedure ground.

Air France pointed also that Algorithm of the Stall Warning has been modified after the accident by Industry.

The pilots' Union ALTER reminds that the origin of pilots' actions is the Pitot tubes misfunction, today modified. Thalès Pitot tubes were replaced by Goodrich sensors after the accident.

[BOAC]

Is it possible that the PNF had less visual feedback on what the PF was actually doing due to the little Airbus sidesticks rather than traditional joysticks? - I don't believe it - the Oozlum bird is off again. Could someone PLEASE put this poster out of their misery?

[Natstrackalpha]

Just one tiny little question . . . .


Did anyone think of using the Standby Artificial Horizon?


I assumed this has been asked, answered and torn to pieces . . ?

[tom775257]

Natstrackalpha: Can I ask a question just out of interest, what is your level of involvement in aviation?

To answer your question: No, they had unreliable airspeed with functional attitude indication so the attitude aspect of the ISIS would have provided no further help than the nice big one in front of each pilot.

[Gysbreght]

At about 02:10:33.6 the PNF said: "According to all three you're going up, so go down". He could have been referring to the two PFD's and the standby instrument, or to attitude, altitude and V/S. Take your pick.

[Machinbird]

At about 02:10:33.6 the PNF said: "According to all three you're going up, so go down". He could have been referring to the two PFD's and the standby instrument, or to attitude, altitude and V/S. Take your pick. Altitude is the only thing that makes sense.

The PFD method for displaying altitude did not help this crew in altitude awareness. The old counter-pointer altimeter display would have been much more explicit as to what was happening.

[DozyWannabe]

The PFD method for displaying altitude did not help this crew in altitude awareness. The old counter-pointer altimeter display would have been much more explicit as to what was happening.

How so? The altimeter "tape" does scroll in the direction and at the rate that the aircraft is climbing/descending, in much the same way as the old "steam gauges" rotated/unwound.

[roulishollandais]

@DozyWanabee
The eye is much more sensitive to a variation of angle than to a linear movement. Experience that with an ordinary digital photo camera watching clouds passing by in the wind. Moving clouds is very visible to the naked eye following clouds angularly - also particularly close to the line of sight - but on your screen your image becomes linear clouds seem to have stopped. :}

If indeed the rate of descent of the scale was equal to that of the aircraft we should not be able to read altitude, I remember a 50m /s freefall near a cliff, believe me, it scrolls very very fast! Impossible to read altitude on that Cliff/virtual screen ! :}

In the HUD KLOPFSTEIN emphasized the need to have the same angular distances threw the HUD and threw the windshield. You don't have that with the bird, or worse thé blue digits emerging above or under the yellow figures. :}

[Machinbird]

How so? The altimeter "tape" does scroll in the direction and at the rate that the aircraft is climbing/descending, in much the same way as the old "steam gauges" rotated/unwound.Dozy,
You need to hand fly on instruments using both systems, then tell us which you prefer, but first you will have to develop and perfect a scan.

Remember? The crew of AF447 was tasked to suddenly take control and hand fly their aircraft. They failed this elementary task. One of the first things they lost control of was maintaining altitude.

Obviously, both systems of altitude display work, but which works better from the human standpoint?

The scrolling tape is essentially a rate signal and is easily picked up, but the actual altitude being traversed requires the eye to focus on the numbers, which then must be mentally interpreted as an altitude differential.

The counter pointer type display is more nearly an actual altitude error signal and for small errors, it is easy to pick out the amount of error by the angle of the 1000' needle as stated by roulishollandais. For rapid climbs/descents, the rapidly rotating 1000' needle draws attention to itself and is unmistakable.

[DozyWannabe]

@roulis, Machinbird:

You've sent me off on an interesting bit of late-night quickfire research on the subject, so thanks. :)

Roulis, you're almost certainly correct in terms of theory, but as always the devil is in the details - or in this case, the context. M. Klopfstein's early HUD research was groundbreaking - and indeed a quick check shows the HUDs of European-made fighters to have a basic circular display (one 'needle' plus digits in the centre), the F-16 to have a linear vertical tape display (similar to civil PFDs) and the F/A-18 to have a digital display only. However then - as now - an HUD is intended to be complementary and/or supplementary to the primary flight instruments, and not a single point of reference in itself.

As far as primary flight instruments go, a bit of Google-bashing drew my attention to a seminal 1949 report for the Journal of Applied Psychology by one Walter F. Grether - probably the best retrospective can be found at this link:

http://repository.asu.edu/attachments/93949/content/tmp/package-2QGKqm/English_asu_0010N_11979.pdf

However, further supporting info on the study can be found with a Google search on "Grether 1949 altimeter".

The gist of the findings was that the traditional three-pointer dial design proved to be by far the most susceptible to misreads, and the optimum dial design used a single pointer with a dual-drum digital counter (which I'm guessing evolved into the combination drum/pointer altimeter that later became nearly ubiquitous prior to the advent of the PFD). The study also noted, however, that the vertical "tape" design (at a concept/experimental-only stage at the time of the report) was very close in terms of speed of reading and not far off in terms of reading accuracy.

It's worth reading through the article linked above, as it gives a very useful precis of how the modern civil PFD evolved, and some very interesting background info on the primary design considerations - the short version being that, as ever, it was a compromise.

Circling back around to the original point, I think the only thing we can be largely certain of is that the PNF was referring to the two PFDs and the standby in general rather than a specific area of the PFD. Taking that into account we know that if everything bar the ASI was functioning correctly, the ADI would have showed the aircraft nose-high, the altimeter's digital display would have been increasing with the "tape" and supplementary pointers indicating an increase, and with the V/S pointer ("vario") indicating a climb.

Notably, the V/S indicator is an angled pointer (albeit 'virtual'), and this would tend to indicate that the designers of the Airbus PFD knew that being able to read this at a glance would be important. Later in the sequence, the PF does refer to being unable to read the "vario", but if I recall correctly this was after the aircraft was well established in the stall, descending rapidly and with the consequent airframe vibrations making the display more difficult to read - something which would have still been the case with a "steam-gauge" V/S indicator.

So at the point in the sequence being discussed, the PNF at least was able to ascertain that all three PFDs, when taken as a whole, indicated that the aircraft was climbing.

@M'bird - I think our posts crossed in the ether, so I'll respond here if that's OK.

Remember? The crew of AF447 was tasked to suddenly take control and hand fly their aircraft. They failed this elementary task. One of the first things they lost control of was maintaining altitude.

True, however I think that interpretation is lacking in a few pertinent details which are important in this case. Firstly, the crew were handed control of the aircraft as you say - but that does not necessarily mean immediately making control inputs without first properly assessing the situation, which is what the PF did here. Learmount, whatever you think of him, is probably on the money when he says that if the PF had done nothing, the aircraft would probably have remained fairly stable - a bumpy ride, certainly, given the weather conditions, but in actuality plenty of time to observe and assess before reacting. Secondly, the PF's immediate response (pulling up on the sidestick) looks very much to me like a textbook "startle response" (similar to ColganAir and West Caribbean) - this in effect compounded a second abnormal situation on the PNF before the latter had time to process the first (being the AP drop-out and UAS). Thirdly, the PF seems to have developed an erroneous mental model very quickly - but fails to communicate what he thinks is wrong to the PNF. To my mind, this means that there was no effective "crew" as such, just two individuals - one whose SA quickly deteriorated, and the other trying to work out what was happening with a rapidly worsening situation.

Obviously, both systems of altitude display work, but which works better from the human standpoint?
...
The counter pointer type display is more nearly an actual altitude error signal and for small errors, it is easy to pick out the amount of error by the angle of the 1000' needle as stated by roulishollandais. For rapid climbs/descents, the rapidly rotating 1000' needle draws attention to itself and is unmistakable.

Right, but as I stated above, the V/S pointer is angled, to assist determination of climb/descent at a glance in concert with the altimeter tape. It was certainly effective enough for the PNF to state that all three displays indicated "going up" (presumably nose-up and climbing) before he started becoming confused and second-guessing himself.

[Machinbird]

Dozy,
To be sure we are communicating effectively, look at figure 5 in this reference http://www.jaa.nl/secured/Operations/WGs/EQSG/Working%20Papers/VFR-IFR%20Equipmnt/CDP%20Altimeter/Altimeter%20TGL.pdf (http://www.jaa.nl/secured/Operations/WGs/EQSG/Working%20Papers/VFR-IFR%20Equipmnt/CDP%20Altimeter/Altimeter%20TGL.pdf)
That is what I am calling a counter-pointer altimeter. The ones that I flew with omitted the last two (static) zeros on the display, but I trusted my indications well enough to fly near the water behind the boat on an ink well night without an operational radar altimeter.
This same basic display has been replicated digitally on some PFDs and works almost as well as the real thing.

Your last assessment of PF's performance is actually very close to my own with the exception that you have completely omitted the effects of the initial overcontrol induced roll PIO on PF's mental state.

Since so few pilots have any actual experience with the subject of PIO (and my own is minimal but not zero) they have no concept of the experience, but to me it was an eye opener.

What both AF447 crew members badly needed that night was to understand just how badly they were off altitude, then the airspeed implications would have been obvious.
They did not need rate based displays so much as a clear presentation of total altitude error in a manner that they could easily absorb under the stress of the moment.

[DozyWannabe]

To be sure we are communicating effectively, look at figure 5 ... That is what I am calling a counter-pointer altimeter.

Sure - if you look at what I wrote quickly, you'll see I mentioned "...the optimum dial design used a single pointer with a dual-drum digital counter (which I'm guessing evolved into the combination drum/pointer altimeter that later became nearly ubiquitous prior to the advent of the PFD)". The latter of which was a reference to the design you describe - apologies if that wasn't clear. The point I was trying to make was that the drum/dial design only scored marginally better then the experimental mechanical "tape" displays, and the additional information and graphical designs afforded by a CRT/TFT display would likely help reduce the discrepancy further.

Your last assessment of PF's performance is actually very close to my own with the exception that you have completely omitted the effects of the initial overcontrol induced roll PIO on PF's mental state.

Yes - I omitted it because my post was already tending towards essay-length! :ok:

What both AF447 crew members badly needed that night was to understand just how badly they were off altitude, then the airspeed implications would have been obvious.

Except that going by the CVR, there is no indication that the crew were unaware of what the altimeter display was telling them. I think what confuses the issue slightly is that translation from the French tends to mix up whether the PNF in particular is referring to pitch angle or altitude (hence the translation into "go up" and "go down" can refer to either). That said, whenever any of the pilots refers to the altimeter specifically after the stall has developed, they consistently say "You're going down", or words to that effect. The PNF is especially emphatic in this regard a couple of times.

[Derfred]

The altimeter wasn't the problem.

The problem was that they didn't look at their PITCH ATTITUDE.

[DozyWannabe]

The problem was that they didn't look at their PITCH ATTITUDE.

With all due respect, I'm pretty certain they did. What they didn't do was effectively work together as a team to understand what the ADI and altimeter was telling them, and consequently solve the problem/recover.

My personal layman's interpretation is that the PF never really recovered from the initial "startle" response, and subsequently developed an inaccurate mental model of the situation. The PNF seems to have had a much clearer idea about what was happening, but lacked the confidence to emphatically take control and tell the PF to back off until he calmed down*. The Captain arrived too late to see the initiating events (namely the zoom-climb and lateral PIO to stall), and therefore only had half the information he needed to assess the situation. I'm pretty sure that the Captain did eventually work out what had happened, but it took the PF's exclamation that he had been pulling up for some time to make it click - unfortunately by then they were only seconds from impact.

* - Because - management/motivational-speak aside, sometimes a member of the team can get overloaded and the other member[s] need to get them to take time out and clear their head before re-engaging.

[gums]

Heh heh, back to the "crowd" from this peanut gallery member.

I agree mostly with Derfred - attitude, not altitude. Just holding the existing attitude and power using inertially-derived sources would seem to have been the best procedure.

The "tape" presentation of altitude in the two planes I flew with them was easy to interpret, and a trend was very easy to detect by the rate the numbers were moving bigger or smaller, duhhhh.

In the Sluf, we also had an instantaneous vertical velocity scale that could be presented next to the altitude "tape", and it could be removed/displayed using our de-clutter options. Sucker sure helped on an ILS or PAR approach. But the flight path marker "ruled", and no air data required. My static system freeze was no problem, even tho that jet's HUD used baro data for the altitude display. Stay on same attitude, use normal power setting and configuration, and wait for the radar altimeter to tell you below 5,000 feet.

I don't side with the 'bird on this one. The rapidly moving "tape" display is a good indication of "trend", and then you might be able to actually read the altitude if the sucker wasn't going as fast as AF447.

back to the peanut gallery.....

[Chris Scott]

Regardless of the relative merits of tape altimeters and the one-rev-per-thousand-feet needle, don't forget that the VS indicator is right next to the altitude tape, and is similar to a traditional VS needle. IIRC, the angle of the green needle increases up to 3000 ft/min** up or down, with a digital value in hundreds of ft/min adjacent to it. After that, it turns amber.

** [Edit] That should probably be 6000 ft/min.

[john_tullamarine]

My personal layman's interpretation is that the PF never really recovered from the initial "startle" response

If so, surely that is no different to any novel situation with a time constraint (ie minimal or no specific experience level able to be applied to resolving the problem) ?

For us old chaps, that sort of consideration (even where not foreseen) was addressed by "over-training" and repetitive simulator stick and rudder work.

[DozyWannabe]

I don't side with the 'bird on this one. The rapidly moving "tape" display is a good indication of "trend", and then you might be able to actually read the altitude if the sucker wasn't going as fast as AF447.

You would - as I mentioned earlier, the Viper used a "tape" display for altitude on the HUD if I'm not mistaken... ;)

Derfred is half right - ADI is important, but where I disagree is that I'm pretty convinced that they were looking at the ADIs, it's just that there was a lack of concerted effort to get "on the same page" when it came to what they meant and what to do about it - in this case I reckon it was because the PF's brain went to panic stations upon AP disconnect, and never really left that state. The PNF tried to snap him out of it verbally, but as has happened many times before (e.g. Birgenair 301, West Caribbean 708), verbal intervention was not enough.

As an aside, I dug up this image which purports to be a real A330 PFD:
http://i1088.photobucket.com/albums/i331/turricaned/a330pfd.jpg

As you can see, at FL400 the most significant three digits are emphasised on the numerical display, and because of this emphasis it should be fairly easy to determine that the numbers are winding down (even more obvious in concert with the "tape" and the V/S pointer).

While I don't doubt 'bird's conviction that a dial display can be perceived marginally more easily when it comes to determining a trend, ultimately there is no evidence that the crew had any trouble reading their altitude from the PFDs, nor that they had trouble telling whether they were climbing or descending.

@Chris Scott - Agreed, and I said as much a wee while ago.

@john_t - While I definitely concur, there is an aviation-specific "gotcha" to startle response discovered as part of the investigation of the A300 over Orly, namely that (IIRC) 80% of pilots will instinctively pull up when sufficiently alarmed, and training should definitely take this into account. Also, sometimes "overtraining" can have unintended consequences - there was an interesting view on the 1977 Tenerife accident which put forward the theory that Captain van Zanten had spent so long training other pilots in the simulator - in which takeoff clearance is invariably automatically given - that his mental model assumed takeoff clearance had been given when in fact it had not. That said, if you have a look at my post in another thread here : http://www.pprune.org/tech-log/538045-flight-international-pilots-must-go-back-basics-6.html#post8493133 , then you can see that I'm very much in favour of airlines putting more emphasis into basic handling (and aeronautics 101) when it comes to training!

On the "old chaps" front, while I'm definitely a believer in the "no substitute for experience" maxim (funnily enough, more so the older I get ;) ) - I think it's worth pointing out that in the Birgenair and West Caribbean accidents, it was the Captain on each flight - both of whom were decorated Air Force veterans - who misjudged the situation, pulling up into the stall and holding it there. In both cases, the younger F/Os correctly diagnosed the stall and tried to get their captain to realise this by prompting them verbally, but could not bring themselves to physically intervene even though it would cost them their lives.

[mary meagher]

Porker 1 brings up the sidestick again, ....what IS the pillock in the LH seat doing now? please, John Tullamarine, has this been completely discounted as a problem? If I was in the right hand seat, could I easily see what the other guy was doing with his left hand??

[Chris Scott]

Thanks for the photo of the PFD, Dozy. The VS indicator "needle" is the horizontal green line to the right of the present altitude, and graduations can be seen above and below it.

Reference to a very old A320 manual suggests that the graduations are 500, 1000, 1500 and 2000 ft/min. The maximum deflection of the "needle" is 2000 ft/min, but (contrary to what I wrote in my previous post) it may not turn to amber until 6000 ft/min. However, there are other triggers for amber, and other warnings when the a/c deviates from the selected altitude set on the FCU. (The current altitude indication on the PFD may flash.)

I think Dozy is probably right that:
"there is no evidence that the crew had any trouble reading their altitude from the PFDs, nor that they had trouble telling whether they were climbing or descending."

mary meagher,

No, the LHS-pilot cannot see what the RHS-pilot is doing with his/her sidestick, or vice-versa. (In AF447, the PF was in the RHS.)

[DozyWannabe]

@mary meagher:

I can't say for certain - obviously it would be more difficult to tell from an objective standpoint. What I found that was interesting during the original multi-thread discussion* was the fact that there were several similar incidents going back at least to Northwest Airlines Flight 6231 in 1974. This number includes Birgenair 301 and West Caribbean 708.

The respective aircraft involved were a B727, B757 and MD-82 - all of which had a conventional linked yoke system as the primary flight control. What I take this to mean is that while it's technically possible for connected flight controls to inform the non-handling pilot through tactile means (whereas independent controls cannot), it's certainly possible (maybe even likely) that such information will be disregarded.

[EDIT : Anyone wanting to see pretty much every angle of the connected vs. independent PFC debate can do so on the original threads - it's a long slog though. I hope I'm not the only one who doesn't want to see any of that ground covered again here! :ok: ]

[john_tullamarine]

80% of pilots will instinctively pull up when sufficiently alarmed

I don't doubt that for a moment.

However, in the absence of anything else going the pilot's way in extremis ... configuration, attitude and thrust is a good place to start when nothing much makes sense - unload the fear and then there is a chance for rational thought to occur. It follows that such data MUST be a memory item .. there is no time to pull out the QRH when the aircraft is at risk of toppling.

In my insular view, training and more training in the basics is the best way to cause a quasi-automatic but reasonable response to fright to occur.

That this may not have happy results in some cases is part of the cost of doing business .. we are concerned with maximising the overall probability of a successful outcome.

Sioux City was an exemplar for how to approach a lost cause, I suggest. A lot of the folks were killed but the miracle that any survived remains ..

Whether the beancounters acknowledge it or not .. when all the aces have disappeared, only the flightcrew remains to sort it out.



Certainly would echo those comments which look to new discussion rather than a rehash of what is contained in the archived megathread on this mishap.

[DozyWannabe]

However, in the absence of anything else going the pilot's way in extremis ... configuration, attitude and thrust is a good place to start when nothing much makes sense - unload the fear and then there is a chance for rational thought to occur.

Right - totally agree. But what makes startle effect especially insidious in an aviation context is that it takes time to "unload the fear", as you put it - even when the person concerned is very well-versed, experienced and trained to automatically respond, sometimes it can overwhelm even that. Making it even more dangerous is the fact that if the person afflicted is PF at the time, then they only have a limited amount of time to overcome the mental overload before the aircraft cannot be recovered. As a result, on top of a greater focus on drilling basic responses and handling, I think it would be an extremely good idea to train pilots on diagnosis of startle effect in colleagues and a cast-iron method of safely dealing with it - even taking control if necessary - until they have calmed down.

Sioux City was an exemplar for how to approach a lost cause, I suggest.

Indeed, and I would add to that example BA038, BA009, Cactus 1549 and the DHL A300 hit by SAM fire over Baghdad.

In the case of Sioux City I think that while the primary crew performed brilliantly by any standard, the addition of the late Capt. Fitch improved their chances significantly, not least because he brought a fresh pair of eyes and analysis to the situation - but also because his presence allowed Capt. Haynes to delegate the task of handling the throttles to him, reducing the task load on the rest of the crew.

I occasionally hear CRM dismissed as a "touchy-feely" exercise, to which I like to point to the UA232 CVR as a rebuttal. I've heard it said that the recording is one of the best existing examples of CRM used in extremis, and I wholeheartedly agree. Not only that, but there's nothing "touchy-feely" about the recording at all!

A lot of the folks were killed but the miracle that any survived remains ..

Indeed, and - while it's a sign of the man Denny Fitch was - I always found it very sad that in every interview given he was still clearly troubled by the fact that not everyone survived.

Whether the beancounters acknowledge it or not .. when all the aces have disappeared, only the flightcrew remains to sort it out.

Absolutely, but management in aviation needs to recognise it too - if not more so.

[roulishollandais]

I think what confuses the issue slightly is that translation from the French tends to mix up whether the PNF in particular is referring to pitch angle or altitude (hence the translation into "go up" and "go down" can refer to either). That said, whenever any of the pilots refers to the altimeter specifically after the stall has developed, they consistently say "You're going down", or words to that effect.I'm finding a difficulty to understand that sentence in French, not first about attitude/altitude (in French from professional pilots it is probably altitude , reference to attitude would mostly use the word "assiette"="pitch") but a greatest ambiguity - and I cannot imagine professional pilots using that expression - is one of the fact which lets me reject the CVR written in a fantasy language, I have NEVER seen by the worst french professional pilot :
In french, when you are saying "tu montes" it has two OPPOSITE meanings, 1. You are climbing ; 2. I'm requesting you to climb, unsaid you are descending. Idem with the expression "tu descends".
Edit add : Inflection of the voice should perhaps help to discriminate, but the BEA did not deliver the vocal tape, and the text is rewritten...

[roulishollandais]

However, in the absence of anything else going the pilot's way in extremis ... configuration, attitude and thrust is a good place to start when nothing much makes sense - unload the fear and then there is a chance for rational thought to occur. It follows that such data MUST be a memory item .. there is no time to pull out the QRH when the aircraft is at risk of toppling.

In my insularview, training and more training in the basics is the best way to cause a quasi-automatic but reasonable response to fright to occur.

That this may not have happy results in some cases is part of the cost of doing business .. we are concerned with maximising the overall probability of a successful outcome.

Sioux City was an exemplar for how to approach a lost cause, I suggest. A lot of the folks were killed but the miracle that any survived remains ..

Whether the beancounters acknowledge it or not .. when all the aces have disappeared, only the flightcrew remains to sort it out.Your description of the heart of the philosophy of french PROFESSIONAL pilots "education" is exactly this one. Doing the student able to resist to the many pressures he will be the focus in his profession, corruption, fatigue, fear, surprise.

@DozyWanabee,
Where is the 80% figure coming from? In any case when you are seeing the speed decreasing instinctive action is to PUSH not to PULL and immediatly after come back to the HSI if speed continues to decrease, to avoid overspeed. If now a roll PIO is starting in alt2B sub-law instinctive action is away, and specialy with an autotrimmed plane you don't grip the stick, more the joy-stick! as if you were on a roller-coaster

[roulishollandais]

I think it's worth pointing out that in the Birgenair and West Caribbean accidents, it was the Captain on each flight - both of whom were decorated Air Force veterans - who misjudged the situation, pulling up into the stall and holding it there. In both cases, the younger F/Os correctly diagnosed the stallIt's a shame for civilian aviation to kill these decorated Air Force Veterans who proved their ability to face much more difficult situations in war and who hàd no more the adequate and enough training once in airlines to avoid a stall.
Beancounters and chief pilots must not be proud of that, to get money of insurance despite their inhumanity and irresponsible behaviour. :ugh:
DozyWanabee, once more you are showing usa cold cynism.

[Linktrained]

In 1949, as a very new "Joy-riding" pilot flying an Auster I was asked to " Loop the Loop" by some of my passengers. This was NOT allowed - by those in authority. ( We did have lap-straps.)


Instead I would push the stick forward and some of the young ladies would squeal. On pulling the stick back, they became silent again.
I ought to have collected, and kept, the statistics. But pprune did not exist to tell .


Perhaps fear of the unknown, how far will I drop, is worse than a hardening cushion!


80 % would seem right... It must have been much more than 50%.

[DozyWannabe]

Should point out that the above linked blog is that of a former head of the SNPL union (notable for their long-standing adversarial stance towards Airbus), so therefore his comments (also downloadable from the page) will likely have a degree of bias to them.

I've had a quick squiz on his commentary via Google Translate, and I don't think his comments cover anything that was not already covered by the archived "mega-thread" on the subject.

[VNAV PATH]

@ winerhofer :

When you will get the contre expertise and its Air Caraibes incident comparaison , do not miss a comparaison with their internal report, bottom of pages 3, 12 and 13..sorry for the non french readers..

http://fr.slideshare.net/Unusualattitude/air-caraibes-airbus-a330-memo

[galaxy flyer]

If startled, 80% of pilots pull back on the controls, training has serious problems. Doing nothing is better than that.

[DozyWannabe]

@VNAV_PATH:

I think the primary discrepancy between the (valid) points made in the Air Caraibes memo and what we later learned of AF447 via the CVR is that in the case of AF447, neither pilot makes any reference (or indeed any reaction) to the Stall Warning even though it sounds continuously for around a minute. In fact, there's no evidence to suggest that the crew attempted to apply any known procedure at all.

@galaxy flier:

That figure came from this report on YR-LCA - an A300 on approach to Orly airport in 1994:

YR-LCA (http://www.bea.aero/docspa/1994/yr-a940924a/htm/yr-a940924a.htm)

(Use your browser's "Find" to look for the relevant section with '80%')

I believe the conclusions and recommendations included more thorough explanation via training of how inappropriate reactions can occur and for pilots to take extra care in guarding against them.

[roulishollandais]

The PF does not seem to have noticed the THS pitch down movement, particularly given that a movement of the THS commanded by the automated systems is not announced by the “whooler”. This triggered a reduction in pitch attitude. The aircraft did, however, stall; the “Cricket” stall warning signal and stick shaker were only activated later during descent (see paragraph 2.3.2 below).

Immediately before, during and after the stall, due the unreliability of the total pressure, the ADC no longer provided speed data, resulting in automatic disconnection of the ATHR, with the throttle levers remaining in the maximum thrust position.

Just before the stall, the Captain pulled the control column* fully back, bringing the elevator to 23 degrees nose up. He then pushed it fully forward, while continuing to counter the roll of 75 degrees to the right with the ailerons. The statistical data shows that, when confronted by a stall, in 80% of cases, pilots pull back the control column, in a sort of reflex movement, which continues the loss of control.

The aircraft was subjected to a series of four full and rapid rolls. The first was attributed to the force brought to bear by the pilot on the left part of the control column; the following ones were due to pilot overcompensation on the roll then the stall. Having pulled the control column fully back and thus caused maximum nose up pitch, the pilot rectified this by pushing the control column fully forward. The aircraft dipped, with its nose going under the horizon by 32°. The roll-off from +50 to –32° in seven seconds was remarkable.
We can't know in that quote :
- which stat data ? Who ? Sim/plane ? Type ? Size and type of population ? Have these results been published in a controlled research paper, etc.
- which pilots ? (Licence, experience, recent training, fatigue, which flight school if any ? etc.
- which stall ? N? Thrust ? Other anomaly (roll, oscillations, ths, spin, aso) ? etc.
- other

[DozyWannabe]

@roulis:

I think it would be fair to presume that the experiments would have been performed as part of the investigation. The context gives two points - when confronted by a stall in that scenario, 80% of the pilots who took part in the experiment reflexively pulled up. If so, then it was an adjunct to the investigation itself rather than a scientific study in its own right. I'd imagine the pilots were taken from a reasonably broad cross-section of those available.

As far as I'm concerned, quibbling over the parameters of the experiments would have been far less concerning at the time than the significant number of those tested who did indeed pull up! I also think that the lack of surprise at the figure from posters known to be experienced pilots is rather telling.

Going back to a previous reply of yours - the point I was making regarding other incidents in which ex-military captains were responsible for pulling up was simply to highlight that it would be unwise to "write off" the actions of the AF447 PF as being purely down to inexperience.

[roulishollandais]

@DozyWanabee
1. It has been said again and again that training was a major factor in AF447. I don't remember that inexperience has been pointed as such a point. Why don't Airlines maintain the level from skilled pilots like these Vétérans ?

2. You know that math was my first learning. In that immense matter, I used "some" time in stats ! Real stats. Not what we are used to read in magazines, because stats are not very pleasant to understand nor to read... And no aviation investigation wants to give you a pleasant reading ! or a complete demonstration.

Please watch, about Airliners stall, on one hand we are reading that test pilots don't stall airlines, on the other hand we should accept that airlines pilots (likeTarom) should have done an experimentation with 80% pilots pulling the stick at any startle factor... Where are these experimentations ? they don't exist !

[bubbers44]

When we were hired as new FO's on my first airline job not one of us needed training to instinctively release back pressure and lower the nose if we encountered a stall. We were way beyond that basic stuff at that time.

Yes, it was covered again in training for the 737 but it was just a review. Blaming airline training for this accident would only apply to inexperienced pilots that aren't ready for the job yet.

[DozyWannabe]

Blaming airline training for this accident would only apply to inexperienced pilots that aren't ready for the job yet.

You might be inclined to think so, but of 5 incidents I can think of involving airliners where the crew pulled up into a stall, 4 of them had the Captain as PF and at least 2 of those captains were ex-mil veterans.

The "inexperienced/magenta line" argument doesn't seem to hold with the historical record here.

[DozyWannabe]

@Winnerhofer - to be honest, for the most part I disagree.

In general, the article seems to be based around the assertion that the flight crew are being assigned primary responsibility for the accident - which is, as stated before, fiction. In fairness, it does at least seem to acknowledge that the BEA report enumerates the known contributing factors without assigning responsibility. But it seems to ignore the fact that the Judicial Experts' Reports are also just a preliminary phase in the ongoing legal process - and nothing has as yet been set in stone regarding responsibility.

Forgive Google Translate, it's the best I can do for now:

THALES - . Failure design Pitot probes
Failure of these sensors seems to be the root cause of the air crash, leading to the sequence of events (including errors of representation drivers) to unrecoverable stall the Airbus Air France.

While the icing of the pitot probes was undoubtedly the initiating factor in the accident, referring to it as a "root cause" is inaccurate. The article itself goes on to mention 30-odd other incidents where these probes iced over, yet in all those cases the aircraft was not lost.

EASA (European Aviation Safety Agency) - Lack of certification of the Pitot probes...

The Thales AA probes met certification requirements - not just for EASA but for all international regulatory bodies. The problem arose because aircraft on the line were encountering scenarios which exceeded the regulatory limits.

AIRBUS - Failure design of embedded & automation flight control software
- Lack of understanding of man / machine interface:
AIRBUS did not properly assess the criticality of the event of failure of the Pitot probes, nor the stall could s 'result. Consequently, it did not set the appropriate procedures for dealing with these degraded modes. It was not planned special training to recover from a stall because the system prohibits any such situation even disabling the PA...

This assertion doesn't make sense. If the crew of AF447 were seen to apply a known procedure in response to the loss of airspeed data, then the article might have a point. This would consist of the crew setting the pitch angle to 5 degrees nose up etc. If that had led to a crash then yes - the procedure would be at fault.

But the procedure was not followed, and the PF pulled the nose up to a pitch angle closer to 15 degrees before even taking time to assess the situation.

AF - The procedure "IAS questionable" (procedure for the blocking probes) - Failure to pilot training -. Lack of feedback
Given multiple flight incidents involving Pitot probes Thales brand before the accident, the company had indeed asked Airbus to replace these probes by BF Goodrich probes (deemed less susceptible to icing), but had not stopped the aircraft for this operation. The procedure called "IAS questionable", defined at the time for processing cases of failure of the Pitot probes was inappropriate (it has also been changed since). Finally, Air France would not properly trained its pilots to the case of failure or recovery stall that could ensue (in his defense stall was deemed impossible by the manufacturer).

The replacement of the Thales AA pitot tubes was ongoing, and in fact it was the airlines that requested the work be a service bulletin as opposed to an airworthiness directive. As discussed above, the existing UAS procedure was primarily aimed towards scenarios involving a lower altitude - but that procedure was not followed in the case of the accident. If it had been, even though it was not tailored for a cruise-level scenario, it is extremely unlikely that the aircraft would have been lost.

Furthermore, Airbus's documentation has *always* been clear on the point that the aircraft can be stalled if the flight control law has degraded from "Normal", so the last sentence is a complete fabrication.

DGCA & BEA - Failure to take into account events precursors :
These bodies have not given the feedback on Thales Pitot probes. 32 incidents of blocking Pitot probes, listed on the world fleet between 2003 and 2009, 28 involve Thales probes. They have not issued the necessary recommendations to AIRBUS, regarding essential to guarantee flight safety modifications on its devices. Moreover, after the disaster, Thales Pitot probes complained were changed urgently on all devices.

This statement seems to be worded to imply that the 32 other incidents must have been handled by the BEA (inferring F-registered aircraft) when this is not the case. The outcome of the worldwide case history regarding Thales AA probes did indeed result in an ongoing program to replace them, and supplementary information was supplied to airlines to handle the problem in the interim. 28 incidents were logged with a positive outcome, so the idea that the aircraft would likely be endangered on every occasion is something of an exaggeration.

Crew - pilot inappropriate Reactions :
Their responsibility rests only on the basis of arguments that seem very light. The pilots of the 447 are scapegoats (too) easy no longer here to defend himself.

Not true - there has been no definitive action as yet which determines that the crew bear primary responsibility.

[DozyWannabe]

AF and DGAC knowingly knew that for the last 25-odd years that training was sub-par.
The warning signs were ignored despite victims being sacrificed at the altar of political expediency.
3 fatal crashes ignored: Habsheim, St Odile and Roissy and many non-fatal disasters...
The fast-tracking of F/As on to the RH-seat due Union pressure over more qualified crew is scandalous as well as unsackable incompetence.

Sorry, but with all due respect those conclusions are drawn too simplistically.

For one thing, the crashes you refer to were all flown by experienced (civil) veteran crews. Additionally, the Mt. St. Odile accident was an Air Inter flight, not AF.

For another, I believe that the only member of the flight crew on AF447 who had come up from being a former FA was F/O Robert - and based on the evidence we have I'm convinced that he was probably the most aware of the flight crew as to what was happening, though, tragically, he seems unaware that was the case, and did not assert himself accordingly.

To be fair, I think there's enough evidence doing the rounds to suggest that at the time of AF447, AF was not a "happy" airline and had not been for some time. Furthermore I make no secret of my opinion that the SNPL union is in many ways - and to put it mildly - misguided.

That said, I think that drawing an inference - as you seem to be - that these events mean that the DGAC is somehow deliberately turning a blind eye is not supported by the evidence. At the very least, the DGAC are by no means the only offenders when it comes to not noticing airlines pushing the boundaries of regulations - the US FAA and their regional airlines' working practices are another infamous example.

[jcjeant]

At the very least, the DGAC are by no means the only offenders when it comes to not noticing airlines pushing the boundaries of regulations - the US FAA and their regional airlines' working practices are another infamous example.

We must never excuse the bad practices of one by taking as exemple the bad practices of another
It goes back to both apologize and in fact approving bad practices !

[jcjeant]

For another, I believe that the only member of the flight crew on AF447 who had come up from being a former FA was F/O Robert

The best that Google can do :)

Recruitment of Drivers with Air France: Officially described today, three streams feeding pilot hiring in Co.
Drivers Cadets, ENAC, Drivers Air Force and Naval Aviation, Business Drivers
Drivers Cadets: These are men and women recruited Contest (Bac +2) and not strictly have no aviation background. They are intended to complete training at Air France, under the educational and cultural responsibility Instruction Air France. First flight on light aircraft and private pilot license (flying club) they evolve to the Professional Driver license accompanied by the qualification of flight instrument now called CPL / IR for Commercial Pilot License / Instrument Rules.
If successful this cycle, and after completing flight simulator (Airbus A300) a general adaptation training flight on Jet, including capacity building in terms of "basic skills" (keeping speed with the use of thrust in manual control with only classical instruments ie artificial horizon, airspeed indicator, altimeter, vertical speed indicator, "needle and ball" they are offered for a qualification on Airbus A320, which marks their entry into the Co. .
During this adaptation Jet (conventional aircraft: Airbus A300 Simulator) stall is studied and shown in various configurations.
Contrary to the destroyers Airbus from this so-called "generic aircraft" phase, the stall is studied, taught, and practiced the most universal manner, which "requires" priority to the reduction of incidence, and prudence in setting thrust ...
It is also clear in the Instruction formal document that this practice output approaching the stall is valid for all types of aircraft, including aircraft FBW (Fly By Wire "as the Airbus A320/330 / 340 and B777.
Pilot Pierre-Cedric Bonin and Frederic Naud (crash Toronto for the latter) have never been recruiting from "Cadet" said yet
"Ab Initio". Never! For the simple reason that they have both joined Air France as Steward, and enjoyed enormous benefits of Enterprise Committee of Air France to perform at the flying club their first Air France flight hours privately.AIR FRANCE : Sélection des Pilotes et recrutement interne (http://blogs.mediapart.fr/blog/herve-labarthe/070614/air-france-selection-des-pilotes-et-recrutement-interne)

[DozyWannabe]

We must never excuse the bad practices of one by taking as exemple the bad practices of another

Agreed, and that's not what I'm saying. What I'm saying is that the conclusion Winnerhofer is drawing - namely that the DGAC knew of issues at AF and wilfully ignored them - is not supported by the evidence.

Regarding former FAs on the flight deck, I'll confess I was incorrect and Robert was never a FA. However, according to the Final Report neither was Bonin - the only flight crew member noted as having converted from CC was in fact Capt. Dubois - and the process of conversion lasted from 1979 to 1982 - hardly a recent event!

[roulishollandais]

DGAC knew of issues at AF and wilfully ignored themAir France pilots are working as experts toward the DGAC threw the official OCV and the official Jury des Examens du Personnel Navigant Professionnel.
Air France has his own official Medical Center too.
The Air France autority above the supposed independant BEA is better hidden, but appears occasionaly. I.E. in the Ste Odile crash the AIR INTER pilots used AIR FRANCE approach charts (Melting of Air Inter/ Air France had already started) without "FAF" !!!!!Take time to reread the report, you find no recommandation to add the FAF position missing on ...ALL the AF's approach charts!!!! But AF modified very quickly ALL his approach charts (ATLAS/AIR FRANCE) adding the FAFs' positions.
In the Ste Odile crash missing FAF allowed descent at the 15% (ground) rate from 3660 Ft - D9 Nm to STR until the STR VOR altitude 1340 Ft.... threw the BLOSS , with CFIT at 2620 Ft reported by the BEA without that analysis).
The official chart had the FAF position (7NM to STR) : AF drawed their own charts, not applying the ICAO rules (known as PROMIN in the French law.
Dozy, Do you need other examples of the DGAC dependance toward Air France?

[DozyWannabe]

Did any of those action break regulations though?

I don't see how any of them are illustrative of "dependence", just insufficiently rigorous practice at the time, which was presumably changed.

More to the point, all this was long before AF447, so I don't see the connection!

[DozyWannabe]

Dubois started off as an F/A many moons ago.
Reluctantly became a Captain at an advanced age as he wasn't ambitious at IT.

Really? The report states that he obtained his PPL in 1974, then joined AF as cabin crew from 1976 to 1982, during which time he was clearly engaged in a career path towards flight crew as he obtained his qualifications during the same period. His career with the airlines began flying Caravelles for Air Inter - a type (and airline, for that matter) not known for being automation-heavy. Reading between the lines it looks to me like Dubois always intended to be a pilot, and joined AF as cabin crew to assist his career potential.

I'd like to know the source of your info there, because it doesn't tally with what I'm reading.

Bonin was fast-tracked from F/A on to the RH-seat as well as other 30 F/As in the Summer of 2008.
This is why Dubois pertinently asked: "T'as le PL, toi?"

That's a bit of an assumption - again, I'd be interested in your source, because dear old Google is failing me, and the report doesn't mention Bonin ever being CC.

Remember the AF346 crew at YYZ?
Both were ex-F/As who have since been happily promoted on the A388's flightdeck.

That may well be the case, but again I put to you that it's a bit of a stretch to claim a correlation. For one thing it was a technically difficult approach due to the weather (not to mention that the crew were fatigued, and the charts for YYZ did not include landing distances), and also I can think of several similar incidents off the top of my head (AA1420, QF1, SWA1248) in which the crews were not former FAs.

[angelorange]

Training is the foundation but experience is the walls and roof.

The FO and SO on AF447 were sponsored fast track JAR "integrated" students
Who had minimal time on hand flown machines then straight intoFBW automated Airbus 320s before burning thousands of hours on autopilot in the a330/340.

Even the big JAR/EASA "integrated" and MPL schools admit 80% of these students are scared of flying in light aircraft, scared of stalling and more interested in a lifestyle than aeronautics.

At the time of AF447 disaster I met one cadet on a six month flexi crew co tract with a uk airline. They did not understand why they shouldn't climb too early at high weights nor what Mach buffet was.

Add in the stupid stall recovery taught for min height loss instead of angle of attack reduction BEFORE adding power on FAR25/EASA25 machines and very poor simulator stall replication plus Airbus myth about TOGA and angle of attack protection and you have such a sad waste of life.

[DozyWannabe]

@Winnerhofer:

Admittedly the OCR/translation tools at my disposal are crude, but I can't find a reference in that letter to either Dubois or Bonin being former cabin crew.

Furthermore, as far as I can tell the source seems to be something of an inveterate writer of letters on various subjects - all the others I've found seeming to be unrelated to aviation.

The FO and SO on AF447 were sponsored fast track JAR "integrated" students Who had minimal time on hand flown machines then straight intoFBW automated Airbus 320s before burning thousands of hours on autopilot in the a330/340.

First point - I don't know of F/O Robert's history, but I do know that F/O Bonin was an accomplished sailplane (glider on this side of the pond) pilot. You can't push buttons to fly one of those, and to say the least to fly gliders well requires a very thorough knowledge of aspects of flight, including energy management and stall avoidance.

Second point - With due respect it's a bad idea to get FBW and automation confused or conjoined. They are two very distinct concepts with very different roles.

Even the big JAR/EASA "integrated" and MPL schools admit 80% of these students are scared of flying in light aircraft, scared of stalling and more interested in a lifestyle than aeronautics.

Bonin was not one of these - see above re: gliders.

Add in the stupid stall recovery taught for min height loss instead of angle of attack reduction BEFORE adding power on FAR25/EASA25 machines and very poor simulator stall replication plus Airbus myth about TOGA and angle of attack protection and you have such a sad waste of life.

As the original thread discussed, what you are describing is not a stall *recovery* procedure but a stall *avoidance* procedure. The industry as a whole shifted focus in recurrent airline training to avoidance rather than recovery - meaning that there were pilots whose last stall recovery procedure was flown as part of their PPL exam.

In the wake of AF447, both Boeing and Airbus worked together to develop new procedures and training materials to bring recovery back into the picture.

I'm a little unsure what you mean by "Airbus myth about TOGA and angle of attack protection". Could you elaborate?

[Lonewolf_50]

Add in the stupid stall recovery taught for min height loss instead of angle of attack reduction BEFORE adding power on FAR25/EASA25 machines and very poor simulator stall replication plus Airbus myth about TOGA and angle of attack protection and you have such a sad waste of life.
Teach process, and results speak for themselves. A much underappreciated point. Tip of the cap for you raising it.

[DozyWannabe]

Teach process, and results speak for themselves.

Hmm... Do you not think that process has its place? I agree that it shouldn't be the be-all and end-all, but I've heard far too many pilots interviewed after successful recovery from an incident saying words to the effect of "things went south really fast... and then the training kicked in" to dismiss it entirely. Going back to procedures when the situation threatens to overwhelm your cognitive functions can be a very useful thing, and when applied correctly can seem to be a lifesaver.

In the case of AF447, it seems likely that no procedure was ever followed from AP disconnect onwards, and the unfortunate PF remained overwhelmed from start to finish.

The media have focused on the PF being the least experienced flight crew member in terms of hours, and that seems to have led to an assumption in some quarters that he went straight into the RHS of an Airbus and did practically nothing but program the automatics and fly the occasional take off and approach. This is not true - while the lack of high-altitude manual handling training definitely didn't help, the PF - as I said above - was a sailplane pilot, and apparently qualified to a high degree in that regard. There is no "Otto" or "George" in a sailplane, and if you stall the wing in one you'd better get the nose down, because there is no TOGA setting to power out of it.

I'm still rather concerned that the "inexperienced PF" angle is getting more play than the "startle effect" one.

[jcjeant]

the PF - as I said above - was a sailplane pilot, and apparently qualified to a high degree in that regard. There is no "Otto" or "George" in a sailplane, and if you stall the wing in one you'd better get the nose down, because there is no TOGA setting to power out of it.I think that whatever experience Bonin had with flying gliders .. does nothing when a qualification and experience of flying an Airbus ... or any other jumbo
Between a glider and Airbus .. this is the day and night .. and certainly when it comes to maneuvering as to avoid a stall or worse .. get out
How many "laws" have a glider ?

[DozyWannabe]

One, and it's "get the nose down".

[safetypee]

A thought on training; but not related to any operator, crew, or individual.
I sense that some First Officers might not be sufficiently exposed to critical aspects during training, either due to insufficient instructor emphasis, or not really taking a keen interest in these aspects because of the belief that they will not be exposed to such situations in their current role.
The underlying theme is that critical and targeted refresher training is predominantly for Captains only – they are there to command and take control. Thus First Officers are only required to jump through the hoop - an operator’s perspective, or - this doesn’t concern me as a ‘less than fully engaged’ individual (lacking motivation).

If this is so, an accident investigation could interpreted this as poor or insufficient training, without the basic standard of training being found unacceptable. Also, a First Officer, if ‘in command’ at the time, might find an unexpected critical situation much more surprising (startle) than might be assumed, due to the lack embedded knowledge from training weakness / attitude.

[jcjeant]

One, and it's "get the nose down".

We should expect the worst when a constructor will build a FBW glider :bored:

[roulishollandais]

Did you read anywhere which was the experience of Bonin as sailorplane pilot and recent experience ? Had he the time and opportunity to maintain his skills ?

Do often sailorplane pilots stall without visibility with PFD, unfamiliar alt2B jumping in the third's man seat and oscillating the plane on roll axis and autotrim working without observability in silence ?

Aerobatics gesture culture loss replaced by SOPs culture rejected wise definition of "basics" and was cutting some physical degrees of freedom usable to judgement, decision and piloting.

I remember that sad year -1979- in France when DGAC started to stop and sell their Zlins and bought the C310 to allow Mr. Debiesse responsible of " Formation" to visit the instruction centers with the NEW METHOD and find... fresh meat... he said he needed some times a day... A insurance specialist traveled often with him for her business.
True and incredible : training instructors learned to build paper planes instead to fly in all positions...
I was not alone to see that starting corruption of the whole aviation french civilian system, and I have been sometimes asked to close my eyes and to accept to work with people of that system ( I always refused and I had to pay the price of that refusal)

One year later the ATPL theoric exams traffic started and stayed unpunished forever M.Arondel president of exams Board and later Moureaux, Gourguechon, etc. Ten years later the "A320 not stalling" mantra was accepted like a dogm of the "Dereglementation" religion. Entering in an airliner cockpit you lost outside all your knowledge (aerodynamics, aerobatics, maths, experience) and you were requested to forget any question. These who refused were called dynosaurs and to extend that in a New age french aviation culture they started the "cadets'" system using the prestigious name but not quality of the US Cadets where the older french pilots learnt to fly after WWII. Airbus was requested to build new concepts for these fresh meat pilots. The only improvement I have seen in that system change was the decreasing number of drunk pilots in airline cockpits...

[noske]

There is no "Otto" or "George" in a sailplane, and if you stall the wing in one you'd better get the nose down, because there is no TOGA setting to power out of it.
Problem is, how can you be sure that your A330 is about to stall, when the speed tape is gone? The aircraft had very convincing evidence for the approaching stall (increasing AoA), but had no means to convey it to the pilots in an equally convincing manner.

[DozyWannabe]

@noske:

I'd say the rattling "cricket" noise and the voice blaring "STALL-STALL" should have been a clue...

[blind pew]

Roulanhollandias
Like your post but france wouldn't be the only lot who had a similar arrogant outlook.
Was on the first course that forsaked the chipmunk and aerobatics for a PA 28.
The odd hours that I flew one was a waste as my instructor was too frightened to fly aeros.
Shame to think that AF pilots aren't allowed a glass of plonk with their crew meal though ;)

[roulishollandais]

Problem with alcohol is that some persons are quickly addict after drinking only a bit wine, and get unable to chose the apropriate moment, quantity and quality to taste wine or stronger alchool things (never in flight or time before flight, of course, as ruled by airline and health discipine).

[Lonewolf_50]

Hmm... Do you not think that process has its place?
Dozy, will you please read my post again. You utterly missed my point.

"Teach process" was a direct follow on to the post I replied to, and is shorthahd for training, which is what you rely on when you need it.

You seem to forget that I spent some time as a flight instructor, and at a higher level later on in my career working on pilot training, training methods, and traning systems. Sorry to use brevity there, it seems to have gone over your head.

:ugh:

[noske]

@Dozy: The fact remains that the pilots either didn't believe the stall warning or didn't even perceive it at all. Which caused BEA to recommend (4.2.2)...
... that EASA and the FAA evaluate the relevance of requiring the presence of an angle of attack indicator directly accessible to pilots on board
aeroplanes.And I'd say that some kind of instrument for PNF to point at and say "tu vas décrocher, tu vois? il faut descendre" would have been a great help.

[jcjeant]

@Dozy: The fact remains that the pilots either didn't believe the stall warning or didn't even perceive it at all. Which caused BEA to recommend

Indeed in the CVR ... it's only a synthetic voice for the word "stall"
Never one of the 3 pilots will pronounce the word "stall"
Is this alarm is often a false alarm on this type of aircraft?
Is that during their careers .. these pilots have had to make the experience of several false alarms?
The phenomenon of "tunneling" may be excluded ... for 3 with the same phenomenon at the same time for the same event is difficult to understand
Mystery stand ......

[DozyWannabe]

Dozy, will you please read my post again. You utterly missed my point.

"Teach process" was a direct follow on to the post I replied to, and is shorthahd for training, which is what you rely on when you need it.
I didn't forget, sir - and I don't want to argue with you. Maybe it was my bad for misunderstanding, but the previous post to which you replied referred to "the stupid stall recovery [being] taught", which you actually underlined in your quote. Therefore it appeared to me that you were saying that "teach[ing] process" was a *bad* thing. Apologies if I got it wrong.

@noske - The mega-thread went on a lot about AoA indicators and mechanical stick shakers in the same way - but how does that help the other 5 "pulling up into stall" accidents when they all had shakers?

Also, I don't think the PF was pulling up because he consciously thought it was the right thing to do - I think he was flailing around because he'd become spooked (which I also believe was the case for several of the other incidents). The gauges present definitely seem to have told the PNF that something was up, but he didn't seem to have confidence enough to take charge.

[angelorange]

DozyWB - you make some good points and I agree both Airbus and Boeing have gone some way to educate the flying public on correct AoA reduction techniques. Flight testing FAR/JAR25 demands AoA reduction then 20% above stall speed before adding power.

Low alt, approach to stall min height loss recovery was stressed by FAA and CAA examiners for PPL and Commercial pilots - it instilled the wrong message at the foundational stage of flight training. In aircraft with underslung engines or tractor propellors adding thrust adds to the pitch up moment (not so much at high altitude grant you). Slowing down also activates aft pitch trim (AF447 A330 had maximum aft tailplane trim) which makes recovery even more difficult as the Thomsonfly Bournemouth stall episode revealed: Air Accidents Investigation: 3/2009 G-THOF (http://www.aaib.gov.uk/publications/formal_reports/3_2009_g_thof.cfm)

The Airbus get out of jail free option (Windshear, Terrain, Woop Woop pull up, etc) was regularly emphasized for LST/Initial Type Rating training - essentially (in normal/non degraded mode) it allows you to get to the light buffet (Cl max) with maximum thrust and no stall. It requires Full Aft stick and TOGA. What did Bonin consistently do in the confusion? The BEA have a video of the flight recorders that has not been on general release - it shows the side stick positions on both sides - the FO also applied aft inputs (his seat was found wound aft at the sea bed).

Bonin was spooked long before the fatal events - read his reaction to the smell of ozone. But his techniques and both pilot's ignoring a stall warner speak of poor training and poor understanding of the situation their reactions had created.

Have you discovered how much gliding Bonin had done and how long it had been since he stalled a glider? The BEA AF447 investigator at a recent RAeS Upset recovery lecture did not consider his glider training to have been very frequent or recent to events.

Apparently the junior crew had practiced unreliable airspeed some time before AF447 and the SIM route was from Rio with drifting ADIRUs.

[DozyWannabe]

DozyWB - you make some good points and I agree both Airbus and Boeing have gone some way to educate the flying public on correct AoA reduction techniques.

Cheers! :ok:

The Airbus get out of jail free option (Windshear, Terrain, Woop Woop pull up, etc) was regularly emphasized for LST/Initial Type Rating training - essentially (in normal/non degraded mode) it allows you to get to the light buffet (Cl max) with maximum thrust and no stall. It requires Full Aft stick and TOGA. What did Bonin consistently do in the confusion?

OK, but was this "option" ever trained at high altitude? It not only looks inappropriate for high-altitude ops, but also seems to be at odds with what the manual states in that situation (i.e. 5 degrees nose up, thrust lock)...

It also doesn't explain Bonin's apparent (and inappropriate) concern about overspeed which followed shortly after, causing him to attempt to deploy speedbrakes. I agree that his reverting to the procedure you describe is a possibility, but the rest of it looks to me like he was throwing almost random elements into the mix (likely due to panic). Nor does it explain why he pulled up so soon after AP disconnect.

Bonin was spooked long before the fatal events - read his reaction to the smell of ozone. But his techniques and both pilot's ignoring a stall warner speak of poor training and poor understanding of the situation their reactions had created.

True, but as I said, 5 other pilots (most of them captains and some of them military veterans) have in the past become similarly spooked and made exactly the same mistake. I refer back to the tests done by the BEA in which 80% of the pilots they studied immediately pulled up in response to an unexpected stall warning.

Have you discovered how much gliding Bonin had done and how long it had been since he stalled a glider?

I think I have something with the qualifications and when he did them kicking around somewhere, but the point I was trying to make was that while training was certainly deficient - it doesn't necessarily follow that Bonin "didn't know how to fly", as the media seem to have suggested.

[jcjeant]

it doesn't necessarily follow that Bonin "didn't know how to fly", as the media seem to have suggested.

Caricature or the future ???
In one month .. start from nothing ... too
https://www.youtube.com/watch?v=OcrpR1YI1qc

[Machinbird]

Seems like perhaps only 0.0001% of airline pilots have ever experienced any form of PIO and most do not understand the implications of the AF447 roll PIO encounter right after the autopilot dropped out.

All that wing rocking that Bonin did had the effect of destroying his trust in the reliability of his aircraft's control system so that later when the pitch control system did not behave as he expected (upon stall encounter), he assumed that that had failed too.

Folks have been minimizing the roll oscillation. Statements such as,"it wasn't that bad", "the roll rates were not that high", "he recovered roll control within 30 seconds" seem to predominate. I maintain that those with that view simply do not understand the nature of the PIO beast.

From my very limited exposure to a roll PIO in an older simulator, two PIO oscillation cycles is sufficient to grab your complete attention, and 30 seconds of fighting a PIO oscillation is a lifetime. The rest of you are going to have to take this on faith unless you also have had some sort of a PIO encounter. (And if you do have such experience, lets hear from you.)

Bonin's roll PIO was started by his initial excessively large roll input. The roll PIO was continued by an incorrect control strategy (Trying to get ahead of the roll oscillation). The reason he fell into this trap starts with lack of training in a simulator in roll direct at altitude (ALT2B mode). The other ~ 35 aircraft that successfully survived loss of airspeeds apparently did not encounter a roll PIO.

That Bonin used to fly gliders has very little bearing on the AF447 outcome. When the chips were down, he could not transition smoothly to manual control under night instrument conditions. If he had been gentle with the controls and had just kept on truckin, this would have been a non-event.

As Gums would say, "That's my story and I'm sticking to it.":)

[RetiredF4]

Machinbird
As Gums would say, "That's my story and I'm sticking to it."

I'm with both of you on that one.

PIO is a very surprising event, and the problem lies in recognising it from the beginning. If not recognized the trained corrective action (to counter the unintended roll) agrevates the problem.

The same applies for the stall situation. Without recognizing an imminent stall situation prior stall warning by analyzing the energy situation of the aircraft (climb- gaining altitude - loosing speed) the stall warning might have been judged as invalid and caused by the failing speed indication. We all had faulty warning lights before, and first thing we do when one shows up or "Betty Bitch" is shouting is validating most of those warnings before acting. Excluding the stall from the equation it comes down to the basic trained behaviour: The aircraft goes down, therefore increase pitch to make it go up again.
That's what they did, and what others with stick shakers did.

[DozyWannabe]

@Machinbird, RetiredF4:

You're right - however if I recall correctly from the mega-thread and the report's DFDR graphs, the PIO was on its way to being stabilised, and was almost there at the point the aircraft stalled (apex of the zoom climb) - suggesting that the PF was at least getting a feel for the roll aspect. Unfortunately the consistent backpressure (intentional or not) while doing so meant that stabilising the roll became something of a moot point as the aircraft went into a full stall.

[Lonewolf_50]

I didn't forget, sir - and I don't want to argue with you. Maybe it was my bad for misunderstanding, but the previous post to which you replied referred to "the stupid stall recovery [being] taught", which you actually underlined in your quote. Therefore it appeared to me that you were saying that "teach[ing] process" was a *bad* thing. Apologies if I got it wrong.
No, my point was to agree with him about teaching the correct process. His point on "min alt loss stall teaching" can have some unintended outcomes in terms of what the pilot has as his objective and actions during stall recovery. The key is to teach the correct stall recovery technique, which will take care of losing altitude (minimize it) by unstalling the aircraft and returning (and maintaining) a flying AoA. IT is in how you teach stall prevention and recovery that the lesson is correctly or incorrectly learned. Teach the correct process.

As to "lower the nose" there's a more technically correct idea behind that regarding "reducing the AoA' though in most stalls reducing pitch attitude will help with the AoA problem one is dealing with.

Sorry to bite at you there, I could have been less terse.

@ Machinbird:
From my very limited exposure to a roll PIO in an older simulator, two PIO oscillation cycles is sufficient to grab your complete attention, and 30 seconds of fighting a PIO oscillation is a lifetime.
Amen, Deacon.

[gums]

Be careful taking advantage of an old dinosaur that can't take any of you up and demonstrate some rather severe aerodynamic conditions, and then how to avoid them or recover.

BTW, Roulli had a great discussion on the USAF tanker crash due to "dutch roll". It seems to have a fair amount of PIO present once the yaw and roll got out of phase.

Retired has one great point about being aware of your energy state, and then your response to an abnormal event. Being low and slow requires a different technique than when you have a warning or loss of a flight parameter ( think airspeed) being high and fast. I can guarantee all that on approach with all the drag devices out and the plane not handling as crisply as when at 400 knots and clean, that my initial reaction for a stall indication was relax back pressure or even push forward a bit. For roll excursions I would relax pressure on the stick and watch for a second or two.

'bird had a great video on the other thread about PIO, and that sucker lost it in about 2 seconds due to his very high "q".

In all fairness to Doze, his idea of the "startle factor" seems to have a basis. But sheesh. We were trained to not get hyper-startled and do things until we figured out what was going wrong.

later from the peanut gallery...

[DozyWannabe]

BTW, Roulli had a great discussion on the USAF tanker crash due to "dutch roll". It seems to have a fair amount of PIO present once the yaw and roll got out of phase.

Aye, but let's not forget that the A330 is a much more modern design and its more advanced aerofoil and yaw damper designs make it much more forgiving.

In all fairness to Doze, his idea of the "startle factor" seems to have a basis. But sheesh. We were trained to not get hyper-startled and do things until we figured out what was going wrong.

Of course, but what I've been trying to get at is that the training as it stands might not be enough. Specifically I'm concerned about the "inexperience" or "magenta line" narrative overshadowing the fact that we've had several accidents now where even very experienced pilots have been spooked by a sudden abnormality and proceeded to respond in such a way that their aircraft was lost. Startle effect isn't a new phenomenon, but it is nevertheless somewhat poorly-understood on the line. To be frank, I'd be inclined to consider it a type of incapacitation that needs to not only be trained against on an individual level, but also trained in terms of recognition in one's colleagues and consequent assumption of control until the colleague calms down.

[roulishollandais]

Aye, but let's not forget that the A330 is a much more modern design and its more advanced aerofoil and yaw damper designs make it much more forgiving.Reading the KC-135 mishap report shows that nothing happened in that Dutch Roll PIO that can't be done with a new A330, any modern or new plane. Dutch roll is the most basic PIO (Pilot induced oscillation). The loss of rudder in flight followed by the total destruction of the plane in three parts and explosion in flight followed by CFIT and fire shows the potentiel danger of any oscillation. The modern data recorder and conversation showed exactly that any modern and new plane cannot resist better to resonance developing very quickly threw the pilot's pedals and feet out of the flight envelop.:ugh:
(Figure 6 page 11/54, figure 9 page 14/54 , Conclusion of Brigadier General Steven J. Arquiette page 48/54 of the 1534 pages report)

[DozyWannabe]

Interesting development, but that journo wants a quiet word had, because this bit:

The autopilot, unaware of the error, lowered the nose of the airplane in an attempt to increase airspeed. Unable to maintain altitude, the autopilot disengaged, at which point three human pilots were unable to correct for the error.

is unsubstantiated nonsense. The autopilot disconnected because of the discrepancy in airspeed, that much is true, but I don't think it lowered the nose. As I recall the aircraft ended up slightly nose-down at disconnect because of a bump of turbulence.

[gums]

Yeah, Doze, et al, whoever wrote the article doesn't seem to understand aero, flight control systems, autopilot implementation, and the beat goes on.

Sheesh. After so many years, one would have a better idea of how the plane worked and basic aero, ya think?

- All of us here have a decent understanding of the basic and reversion control laws for the jet. However, I can't find details on the AP implementation.

I raise this issue due to my Viper experience( early years) when we lost a troop who was on AP and slowly descended into the Salt Lake. Unknown to us at the time, the AP had an AOA limit that was basically half the "normal" limit - think 13 degrees versus 27 degrees. So with a mission abort at heavy weight, the troop turned back and was BZ changing channels, IFF and such while slowly descending in a gray sky with low ceiling and over a lake that was smooth as glass that day. We single seat folks used everything we could, contrary to popular depictions of us.

- With an AP disconnect and a reversion to the next lower law, the "startle factor" is in play, as some here have opined. And then maybe not realizing the system was in a reversion law with less "protection", hence the "pull back" syndrome. After all, "you can't stall this jet, huh?"

- Maybe the AP control laws depended more upon airspeed than AoA? But my understanding is Otto disconnected immediately.

Good grief, this accident will be the poster child of system design, human factors and sensor faults.

[Machinbird]

Folks have been minimizing the roll oscillation. Statements such as,"it wasn't that bad", "the roll rates were not that high", "he recovered roll control within 30 seconds" seem to predominate. I maintain that those with that view simply do not understand the nature of the PIO beast.
You're right - however if I recall correctly from the mega-thread and the report's DFDR graphs, the PIO was on its way to being stabilised, and was almost there at the point the aircraft stalled (apex of the zoom climb) - suggesting that the PF was at least getting a feel for the roll aspect. Unfortunately the consistent backpressure (intentional or not) while doing so meant that stabilising the roll became something of a moot point as the aircraft went into a full stall.
Dozy, have you considered that the one size fits all roll direct control gain became more appropriate as the aircraft decelerated?

As for startlement effects, the initial strong control input that started the roll PIO could have been from startlement, or possibly from annoyance at having to take control. In any case, it was an unfortunate response to a situation that merely required minimal control inputs.

[gums]

I can't find the use of "standby gains" in the pubs I have recieved from you guys. Only the "direct" mode resembles what we used to fly with pure mechanical connections ( no hydraulics).

Seems the "alt" laws still use rate commands, and I can see this if the rate sensors are still active, and no reason to think they would be influenced by pitot-static problems, ya think. We had a Viper fly for about 10 minutes or so after a large pelican smashed the radome and the AoA sensors - no airspeed and no AoA, only inertial inputs, absolute pressure and "standby gains". The damage apparently got to the flight control computers, which eventually failed. The pilot was flying on instruments the whole time, as the blood covered the forward part of the canopy.

So I go with Doze that the roll PIO was pretty much dealt with by the time the jet ran outta energy and defeated the AoA protections ( same as Viper deep stall entry).

I also go with 'bird that the "startle factor" should not have been the primary cause of later control inputs. There was even a call about "alternate" law early on, wasn't there?

Finally, seems to me that the jet's control surfaces would have been trimmed pretty well when the pitots froze and AP disconnected. In short, let the jet go where it is trimmed before doing anything rash and getting into the roll PIO we are theorizing. BTW, I can't seem to find when the pitot system came back on line. If it did, did the input to the FLCS have to be enabled by the crew?

[Turbine D]

One of the things I have often wondered about was the sidestick control, left hand verses right hand. I would think normally the Captain or the pilot in control would be seated in the left seat and using his left hand on the sidestick. However, in this instance, the pilot in control was seated in the right seat and would be using his right hand on the sidestick. Considering the abrupt A/P disconnect and reversion to alternate law, plus the startle factor, might this seating arrangement have played a part in first the roll control situation and then the subsequent continual pitch up problem, e.g., lack of sidestick control sensitivity because of not using the usual (dominate) control hand and sidestick? Would it have an influence or make a difference? Just asking…

[Machinbird]

Dinosaur sir,
You will need to re-read how Alt 1 and Alt 2 differ.
Your forgetter is working too well.:}

Hi Turbine D, Assuming Bonin was right-handed, then he would have been using his stronger arm to fly the aircraft. This made it easier for him to jerk the aircraft around initially.
A number of Airbus pilots have remarked in the past that it would have taken a lot of work to make the lateral control inputs that were made due to the viscous damper in the lateral channel. I suspect that his arm was burning with fatigue after the first 30 seconds and that his ability to make small corrections was then compromised as a result.

[jcjeant]

However, in this instance, the pilot in control was seated in the right seat and would be using his right hand on the sidestick. Considering the abrupt A/P disconnect and reversion to alternate law, plus the startle factor, might this seating arrangement have played a part in first the roll control situation and then the subsequent continual pitch up problem, e.g., lack of sidestick control sensitivity because of not using the usual (dominate) control hand and sidestick? Would it have an influence or make a difference? Just asking…

As Bonin was copilot .. he was used to control the plane from the right seat (so right hand) .. his usal place
Robert had taken the seat (left) of Dubois (captain) ....
So .. no influence there .... AFAIK

[DozyWannabe]

Dozy, have you considered that the one size fits all roll direct control gain became more appropriate as the aircraft decelerated?

It's possible, but given the situation I'm inclined to give the PF the benefit of the doubt and think that he was indeed bringing the roll under control.

As for startlement effects, the initial strong control input that started the roll PIO could have been from startlement ... it was an unfortunate response to a situation that merely required minimal control inputs.

Or no control inputs at all! The A330 is a very stable platform - and whatever one may think of Learmount, I'm inclined to agree with his opinion that with no further inputs the aircraft would have simply ridden out the turbulence as best it could, and after 30 or 40 seconds the ice would have melted from the pitot tubes and the speed indicators come back online.

I'm basing my "startle effect" call on previous similar incidents where pilots made an erroneous initial call on the problem (in some cases because the warning systems were giving misleading signals). Those incidents are Birgenair 301, ColganAir, NWA6231 and West Caribbean 708. In the Birgenair case, the Captain as PF seemed to fixate on the first warning he received, which was an erroneous overspeed. In the case of West Caribbean, the Captain thought he was dealing with a dual engine flameout. In both of those cases, the F/Os correctly diagnosed a stall and inappropriate attitude, but the Captain did not respond.

The other reason I suspect the AF447 pitch input to have been inadvertent is because the two F/Os had been discussing not being able to exceed their present altitude for safety reasons only a few minutes before. At AP disconnect they had well over 30,000ft to play with and they knew that to climb would increase risk. To initiate a climb would therefore be completely illogical, and I suspect this is (at least in part) why the PNF was initially so incredulous as to what seemed to be happening.

I also go with 'bird that the "startle factor" should not have been the primary cause of later control inputs. There was even a call about "alternate" law early on, wasn't there?

There was an "Alternate Law" call from the PNF to which the PF did not respond - we therefore don't even know if he heard it (which - if he didn't - to my mind supports the "startle" theory)

BTW, I can't seem to find when the pitot system came back on line. If it did, did the input to the FLCS have to be enabled by the crew?

You can see the speeds coming back online in the DFDR traces at about 02:10:35 - at that point the aircraft is established in the climb at around 37,000ft.

No, there was no need for the crew to perform an action to bring them back online.

A number of Airbus pilots have remarked in the past that it would have taken a lot of work to make the lateral control inputs that were made due to the viscous damper in the lateral channel.

Did they? Must confess I don't remember so well. As far as I know the primary damping mechanism in the sidestick is actually spring-driven, and the simulator version I had a chance to get to grips with was actually very responsive and not too difficult to deflect once you had it going. The springs do centre the SS, and there is a small degree of 'breakout' force, but once deflected it offers enough resistance to let you know it's deflected, but not enough to cause physical issues.

[roulishollandais]

Origin of that text ???

URA
Unreliable Airspeed

Historical and recent accidents and incidents have highlighted the risk associated with unreliable airspeed (URA) events. These events are normally transient in nature and can cause multiple, seemingly unrelated warnings and failures. The following philosophy and guidelines are provided to assist in reducing the risks associated with URA events.

URA Philosophy
The keys to successfully dealing with a URA event are recognition, procedures, and training
The aircrew’s recognition of and initial reaction to a URA event are critical
Manufacturers should attempt to ensure unreliable airspeed events are clearly identifiable to aircrews
The most important function of the aircrew during an in-flight URA event is to maintain control over the aircraft’s flight trajectory and energy situation by selection of attitude and power settings so that the aircrafts flight parameters remain within normal limits
Crews should be aware of the instruments and critical systems that are not affected by a URA event (e.g. Attitude displays, engines)
Procedures and training for URA events should include the effect of a URA event on other aircraft systems, and potential alerts/warnings and indication system inaccuracies that could be expected
Crew coordination and communication are important elements in successfully addressing a URA event
URA Guidelines
URA procedures should provide information on attitude and power settings that enable crews to maintain the aircrafts flight parameters within normal limits during in-flight unreliable airspeed events for all phases of flight
URA procedures should address the availability and use of independent alternate sources of airspeed information (e.g. GPS, inertial, angle of attack, etc.)
URA procedures should include memory items for critical immediate action steps
Training programs addressing URA should exist at beginning (ab initio/MPL), initial, and recurrent levels
URA training should include both simulator and academic phases

[DozyWannabe]

I suspect it's a Winnerhofer "original". The usual contraction for unreliable airspeed is UAS as far as I know!

That said, the points are fair...

[roulishollandais]

@Dozy
I don't think it is a Winnerhofer original.
Use of "URA" is from somebody who didn't read the BEA report
I don't agree with that complicated "philosophy". Pilots don't fly philosophy, not enough time to "do nothing":*

[gums]

Salute!

O.K., 'bird. I thot the jet was in Alt 1. So Alt 2 is a different beast WRT roll commands and aircraft reactions.

It still bugs me that I have to figure out exactly what law I am operating with.

Seems to me that "stby gains" ( gear up or gear down values) and basic gee commands/protections and AoA inputs should have saved the day. Then there are all the inertial/rate sensors that don't need a single atmospheric input.

When I talk about the various modes, I am talking about limits on max bank angle, max pitch, max gee, ,max AoA, etc. Then there are the control surface rates that depend upon "Q" - the "gains".

Oh well, the AF447 tragedy shall remain the "poster child" concerning airmanship and aircraft software implementaion for at least a few more years.

[DozyWannabe]

O.K., 'bird. I thot the jet was in Alt 1.

This surprises me, because you've certainly been active enough on the thread of doom to know otherwise!

So Alt 2 is a different beast WRT roll commands and aircraft reactions.

It still bugs me that I have to figure out exactly what law I am operating with.

The difference is fairly academic really. I think it boils down mainly to the aircraft being slightly more sensitive in roll - other than that it's fairly transparent.

Seems to me that "stby gains" ( gear up or gear down values) and basic gee commands/protections and AoA inputs should have saved the day. Then there are all the inertial/rate sensors that don't need a single atmospheric input.

We covered this in the mega-thread though. The "soft" protections would have stabilised the aircraft until well into the sequence *had the PF just let go of the sidestick*.

The assumption in the EFCS design is that if there has been a failure sufficient to degrade from Normal Law, then the human pilots are given priority over the systems on the grounds that they are likely to know more than the systems do about the status of the aircraft. Such priority is exercised by being able to override the soft protections via control inputs.

@Winnerhofer - OK, we know AF has had a few issues in recent times, but I'm struggling to understand what you're trying to say by providing us that link.

[roulishollandais]

@Winnerhofer
I was seeing that you replaced the unknown "URA"s by the "UAS"s (i.e. BEA and AF SOP). Much better !

But that text is not usable by pilots in flight and if you teach pilots on ground with that text about UAS they will start to write a book waiting 30seconds (Eternity) until the pitots ice is melted (perhaps never in case of failure) and systems fit again. You have to pilot your bird with pitch and power, that is "doing nothing" but as Machinbird said it "without keeping your hands in your pockets". Gums suggested the good delay for observation, appropriate decision, and starting correction without precipitation : 1 or 2 seconds...

That delay of 30 seconds appeared with A320 in some office. I was amazed since February 1988 that Pierre Baud accepted it.

SOP must be simple, but understanding the SOP during the time you do it must be simple too, as often a succession of factors and results happen in an emergency.

After some months gums pointed alt1 instead alt2b and came back to the C* definition, with limitation and rate limitations from fondamental pilot controlled parameters - pitch, bank, gee, power and their variations with help of reliable information like intertial data. More ordinary pilots cannot do more complicated than gums or Machinbird. Accurate pedagogy is a condition of survival in flight.

[DozyWannabe]

But that text is not usable by pilots in flight and if you teach pilots on ground with that text...

I don't think it was intended for that, I think it was an attempt at a general summary.

... waiting 30seconds (Eternity) until the pitots ice is melted (perhaps never in case of failure) and systems fit again. You have to pilot your bird with pitch and power, that is "doing nothing" but as Machinbird said it "without keeping your hands in your pockets". Gums suggested the good delay for observation, appropriate decision, and starting correction without precipitation : 1 or 2 seconds...

Right, I don't think anyone's suggesting anything different. I think what does need to be pointed out, though, is that outside of a significant mechanical failure or sudden change in the weather conditions being transited, the pitch and power at the point of AP disconnect will usually be more-or-less correct for the conditions, and one should only change it immediately if a significant problem is developing.

That delay of 30 seconds appeared with A320 in some office. I was amazed since February 1988 that Pierre Baud accepted it.

Sorry, need some more detail on this - what are you referring to?

More ordinary pilots cannot do more complicated than gums or Machinbird. Accurate pedagogy is a condition of survival in flight.

As a rule, you don't really need to worry about systems functions at that level. The aircraft will still go where you point it.

[roulishollandais]

That delay of 30 seconds appeared with A320 in some office. I was amazed since February 1988 that Pierre Baud accepted it.

Sorry, need some more detail on this - what are you referring to? Perhaps you can help me to find again that document in a ICAO magazine from january or february 1988, where Pierre Beaud was describing the strange innovations of the A320 : Push the red button 30s after the systems decide you have to learn piloting again, addition of both inputs, A320 doesn't stall. Etc. I no more remember the tittle and exact reference, and since ICAO does no more sell their documentation in Neuily/Seine I found it too difficult to find anything. The aircraft will still go where you point it. where you point your HUD ! Free falling I learned "Body goes where eyes are looking"

[Machinbird]

The difference is fairly academic really. I think it boils down mainly to the aircraft being slightly more sensitive in roll - other than that it's fairly transparent.Dozy, you continue to astound me with your blithe statements on subjects you have little practical knowledge of. That "academic" difference just might have been the difference between AF447 making in into the barn that day and taking that big swim. That sensitivity difference permitted initiation of a roll PIO from what I can see.

[gums]

I am gonna go with 'bird and gang up on the Doze! Heh heh.

There is one helluva difference between the "direct" roll commands in Alt 2 and the roll implementation in Alt 1 ( thanks, 'bird..... I forgot the mode -- exxxxcuuuuseee me!)). My documents show something that looks like "stby gains" for Alt 2 according to configuration, but also states the control surface deflection is directly related to stick delection - full stick gives you full deflection and the "gains" move the surfaces at an appropriate rate ( just like the Viper did over ten years before, except our roll was still a body rate command and not an actual control surface deflection).

So @ Doze: Easier to get into a PIO in Alt 2 than Alt 1 or "normal". Doesn't excuse the "startle" factor we have discussed, if that's what happened, but going from a rate command with all the protections and such to a "direct" mode is not trivial. Feedback to the pilot is basically "seat of the pants" and your inner ear gyros. Not sure what the pounds per degree of stick deflection are, but the Viper was basically 16 - 17 pounds full pressure/rate command for roll ( my leading edge flap failure had me holding about 15 - 16 pounds for the 15 minutes I was airborne just to get zero roll rate in actuality).

Still appreciate your inputs, Doze, and wish I coulda been there withya in the sim and trying to recover the jet. I thot someone else tried a "recovery" from the "top" of the climb and entry to a deeply salled condition.

[Owain Glyndwr]

Just got back home after driving through WW1 battle areas, so I am going to stick my head above the parapet and duck back quickly!

I'm not at all convinced that it is fair to describe the lateral oscillations immediately following the AP drop out as being a PIO, although I can see why people should describe them as such. PIOs, technically speaking, have control inputs out of phase with the necessary corrective actions and the bank angle excursions should be increasing, not falling.

I think the point being missed in the discussions of 'sensitivity' and 'startle' is that there was a fundamental change in the piloting dynamics when the FCS reverted to direct law. IIRC in normal and Alt laws a sidestick movement commands a roll rate, but in direct law sidestick commands roll acceleration as in most aircraft.

Now I am not a pilot, but what I learned in studies of several aircraft is that to get stability the necessary control techniques are very different in the two cases.

What I see in AF447 is a pilot struggling to come to terms with an unfamiliar control dynamic; OK, it is one he had seen before throughout his early career and training, but not one which he had used recently. The (damped) oscillations result from his re-learning process and personally, I think he made a pretty good fist of it. I can't see them as a fault on his part, which describing the motion as a PIO somehow implies.

[gums]

Sounds like a trip thru memory lane, OG

I don't think the "direct" roll implementaion is an "acceleration" command of the control surfaces, but actual control surface position. The "rate" of movement seems to be dependent upon the "gains" that the FCS uses according to aircraft configuration. This was same for the primitive FBW law we had in the Viper - "x" dynamic pressure according to gear up or gear down.

The "direct" command of aileron position is vastly different than commanding a roll rate or whatever. So at stick being neutral, the ailerons should move to whatever position the "neutral" position of the stick is using according to last trim condition.

Our force on the Viper stick was pretty simple, and just relaxing on the stick with zero force resulted in the jet rolling according to the last trimmed roll rate ( usually zero). You can see this on the Thunderbird solo pilots that do rolls to inverted passing in front of the crowd. The sucker flat stops rolling and no overshoot.

Just my experience and observations, but the 'bus FCS seems to implement the Viper laws except for the max bank angle.

[Owain Glyndwr]

Hi gums,

Guess I should have been a little more precise. Direct law does produce aileron movement proportional to stick movement as you say; but aileron movement produces a roll acceleration, which is why I wrote that stick movement commands a roll acceleration. That develops eventually into a roll rate which depends on aileron deflection, airspeed and the natural roll damping derivative. That means the characteristics are speed dependent whereas in the other laws you get the same roll rate for a given stick movement at any airspeed.

Putting the stick back to neutral in direct law will kill the roll rate not leave it at a commanded value as it does in normal/alternate. That is same as non-FBW aircraft and differs from your description of the Viper operations.

[DozyWannabe]

I think the point being missed in the discussions of 'sensitivity' and 'startle' is that there was a fundamental change in the piloting dynamics when the FCS reverted to direct law. IIRC in normal and Alt laws a sidestick movement commands a roll rate, but in direct law sidestick commands roll acceleration as in most aircraft.

You remember right, however in this case the aircraft did not degrade to Direct Law, but to Alternate 2 (the equivalent of Alternate [no speed stability] on the A320 IIRC). In Alternate 1, roll is still rate-commanded, but in Alternate 2 the roll commands become direct. In Alt 2 the pitch commands are still rate-commanded, unlike Direct Law.

While I agree the dynamics definitely change in Alt 2 versus Normal Law, there are two caveats - namely that there was no immediate need to make significant roll inputs upon AP disconnect (and thus risk potential PIO), and that as the PF had no training in high-altitude manual handling at all it is conceivable that he may still have initially overcontrolled even if the roll aspect was still rate-driven.

EDIT : Though, as pointed out, I am not an aviation professional, I do however submit that this should at least be considered a matter of common sense - namely that if a malfunction (which will initially be of an unknown nature) has occurred, then it would be advisable to treat the flight controls very gingerly at first, because you don't know what works and what doesn't. I believe the phrase used in the mega-thread to describe the inputs made by the PF was "stirring the mayonnaise" - and this is something to be avoided absolutely unless there's an obvious and life-threatening reason to do so.

Indeed, most of the incidents and accidents I can think of in which the outcome was at least relatively successful have involved the crews concerned doing just that - "feeling out" the aircraft to see how it responds, what works and what doesn't. Examples include UA232, QF72, BA009 and NWA85 - not to mention the other 30-odd incidents of Thales AA-related UAS problems!

[Owain Glyndwr]

Originally posted by DozyWannabee

You remember right, however in this case the aircraft did not degrade to Direct Law, but to Alternate 2 (the equivalent of Alternate [no speed stability] on the A320 IIRC). In Alternate 1, roll is still rate-commanded, but in Alternate 2 the roll commands become direct. In Alt 2 the pitch commands are still rate-commanded, unlike Direct Law.

Yeah I knew that Dozy, but talking of a lateral oscillation the pitch mode is irrelevant and for all practical purposes my statement that the roll degraded to a direct law is correct even if you label it Alt2

[DozyWannabe]

Of course - I was just being irritatingly pedantic (as usual) for the benefit of thread-watchers who were new to the discussion. :ok:

Generally speaking, I think it's important not to get too hung up on the technical aspects of control laws, as some people's eyes tend to glaze over at the mention of them - while the specifics are definitely of interest to a technical audience, I think the best way of explaining them is in terms of more traditional setups.

Specifically, in real terms, all the control laws and their underlying mechanisms actually do is provide maximum controllability in the event of systems or mechanical failures - the technology means that this re-configuration is automatic, but ultimately it's no more than the equivalent of what a flight engineer would do in the event of a e.g. a dicky hydraulic pump or a stuck control cable on an older type.

The common thread remains, however, that the presence of a malfunction requires a gentle touch with the aircraft until the consequences of the malfunction on the aircraft's handling are understood and compensated for by the crew.

[Machinbird]

What I see in AF447 is a pilot struggling to come to terms with an unfamiliar control dynamic; OK, it is one he had seen before throughout his early career and training, but not one which he had used recently. The (damped) oscillations result from his re-learning process and personally, I think he made a pretty good fist of it. I can't see them as a fault on his part, which describing the motion as a PIO somehow implies.

Welcome back from the fronts Owain.
The definitions of PIO have evolved over time and encompass a broader spectrum of oscillations.
The modern definition of PIO is Pilot Involved Oscillation and gets away from blame and fault concepts. Without the pilot in the control loop, the oscillation does not occur.

You can bet your money that Bonin was not rocking the wings for the fun of it. From his control inputs, I can conclude that he desperately wanted it to stop. Unfortunately, he chose a bad strategy to stop the oscillation and thus exacerbated his problem. If you look at the oscillation cycles, you will be able to see that there were a number of low points in the oscillation amplitudes followed by an increase in amplitude in the opposite phase to the immediately prior oscillation. To me, this is an indication that he attempted to get ahead of the cycle of oscillation.

To him, it must have seemed that he was a little too late with his control input, so he accelerated his control inputs, i.e. went faster. I think that you can see this pattern in aircraft behavior and in control behavior if you look at the timing on a cycle to cycle basis.

Too bad he didn't have prior experience in flying in Alt2 Law. He would have learned that all he had to do was stop making control inputs.

The development and implementation of Bonin's control strategy must have heavily dominated his thinking and almost certainly explains a lot of the otherwise inexplicably bad flying he demonstrated.

As pilots we learn to put our aircraft under accurate control. When we have an aircraft that is not behaving as we command, your whole attention is drawn to the problem, and it is difficult to leave sufficient attention for other important requirements of flying. The one very short roll PIO I experienced in a simulator was traumatic enough to leave a lasting impression. It compared to the feeling you get when you trip and begin to fall, and you are looking desperately for a hand hold. In my case, I was desperately looking around for a visual attitude reference that did not have a time lag in its display. I am relaying this so that the reader can get some idea of how compelling a PIO problem can become.

[Owain Glyndwr]

Originally posted by Machinbird

The definitions of PIO have evolved over time and encompass a broader spectrum of oscillations.
The modern definition of PIO is Pilot Involved Oscillation and gets away from blame and fault concepts. Without the pilot in the control loop, the oscillation does not occur.

Which confirms my fear that I am thoroughly out of date on some things!

To him, it must have seemed that he was a little too late with his control input, so he accelerated his control inputs, i.e. went faster. I think that you can see this pattern in aircraft behavior and in control behavior if you look at the timing on a cycle to cycle basis.

That is my point really. Control of the oscillations is all about getting the phasing of the control inputs right. Roll rate is 90 deg out of phase with roll acceleration, so if he was accustomed to a roll rate response to stick he could have been very confused by an aircraft that took a little longer to develop the response he was anticipating. That would be entirely consistent with your remarks

[Machinbird]

Control of the oscillations is all about getting the phasing of the control inputs rightSometimes getting control of the oscillations just requires the pilot to get out of the control loop, but this is not a one size fits all solution.

I can think of at least one PIO event where this course of action had immediate fatal results.(Sageburner).

[roulishollandais]

Henri Poincaré feared to say that the solar system was not exactly periodic and could be unstable (in the traditional use of "PIO" divergence or non convergent oscillation).We know that periodic dynamic is governed both by phase and frequency, but traditionally lack of math tools focused on the only phase control which does not involve energy use at the contrary of frequence modification.
Another well known oscillation in airliners is passengers' hyperventilation. Frequense of breath is increased by different factors disturbing the CO2 and O2 regulation. Trying to correct it with phase has no chance of success.

Sometimes periodic movements are not more or less sinusoidal oscillations, I.e. chalk squeaking on the blackboard when pushed and doing rapid successions of jumps.

Progressively theory of chaos taught us that difficult art of controlling oscillations.
Multi variable problems are more difficult to describe in short words.

"Pilot" in PIO may be Autopilot too, as we see it in the KC-135R dutch roll report when the captain tried to stop it with A/P. The notion of "fault" is of no use in science. We are concerned by cause.

[Machinbird]

"Pilot" in PIO may be Autopilot too, as we see it in the KC-135R dutch roll report when the captain tried to stop it with A/P. The notion of "fault" is of no use in science. We are concerned by cause. The human is a variable gain device when it comes to aircraft control systems.
For some type of input, you can get either a large or a small output and that output can have further modification as to phase angle or even anticipation of a signal.

The autopilot is a machine that is constrained by its construction and design to create a certain type of output for a particular input. Normally an oscillation involving an autopilot is not considered to be a PIO. As I understand the KC-135R accident however, the presence of human feet on the rudder pedals caused additional inputs to the system that resulted in an increasing Dutch Roll oscillation. If my understanding is correct, then that would be a PIO under the newer PIO definitions.

[xcitation]

@Mac / Chris

IMHO the most perplexing of all the holes in the swiss cheese is the total absence of discussion given to the stall warnings by all 3 pilots. Was it a Titanic belief in the un-stallable nature of the airbus that the warning must be a glitch not even worthy of discussion?
Mac - if the patients heart stops during surgery and you hear an alarm I would hope that it gets someones attention.

[Turbine D]

Gums,

Both Dozy and PJ2 (a former A-330 pilot) did recovery exercises in the SIM. Going back to the original AAF447 Thread #9, this is what PJ2 had to say about one of his recovery attempts:
Post 168 AF447 Thread #9
In the sim exercises, for recovery the SS was held full nose-down from the beginning of the stall warning at about FL360 until the wing was unstalled at about FL250, about 40 seconds total time, with a maximum achievable ND pitch of about -12 deg with an average of -10deg. The thrust levers were in the CLB detent and the THS was initially at 13.6deg and was returning to the normal cruise setting.
With the FPV symbol available, the FPA could be observed just above initially at -40deg, (pitch -10deg).

It began to move, initially very slowly up, about 15 seconds after full ND SS;

- at 29 seconds after full ND SS, the FPA had moved from -40deg, (pitch at -11) to -25deg, (same pitch);

- in the next 5 seconds it moved from -25 to -15, (FL257);

- at 38 seconds after full ND SS the FPA was -9deg, (pitch -5deg) with the wing unstalled and the CAS at 255kts.


One other thing that I think is important from a AF447 historical perspective that PJ2 pointed out discusses "Startled" in a collection of posts:

"Startled" is an invented, psychobabble notion created by non-pilots/non-aviation people in an industry that has been dealing with transport emergencies and abnormals and improving on checklist design, system design and crew performance for same, for over fifty years. Why suddenly does the notion of being "startled" in an airliner cockpit have the currency that it does instead of being examined for what it is actually saying?
Is the trend towards relatively low cockpit experience with commensurate reducing skill standards in combination with highly-automated aircraft technologies where a pilot can now be overwhelmed by anything just beyond training and experience, finding new expressions in terms like "startled"?
If "startled" is the new metric when examining human factors in aircraft accidents then there are some serious questions to be asked of those processes upstream from putting crews into transport cockpits who can handle the profession and the job.

And finally,

I am unconvinced of "startle" - everyone is 'startled' to begin with - I have experienced a massive hydraulic failure on the same equipment and yes, it was initially startling but one reverts to training and deals with the ECAM accordingly. I have no idea why it came apart so swiftly and we'll never know. All we can do is re-emphasize what would have saved this airplane, this crew and these passengers, because this was not an emergency and there was no requirement to do anything other than ensure the airplane was stable while the ECAM drill was done according to Airbus SOPs.

I like PJ2's thoughts here, in effect, everyone is startled when something unexpected happens, it's what you do or don't do after being startled that determines the outcome.

A last point: There is a difference between stall prevention, given the warnings and what is done to recover from an actual stall. This Airbus presentation discusses these differences on pages 11 & 12:

http://fucampagne2008.u.f.f.unblog.fr/files/2011/08/updatedstallprocedure.pdf

Cheers!

[xcitation]

Bonin was convinced he needed to pull the stick back all the time.
So convinced he ignored the nose up attitude, decaying airspeed, stall warnings, alarms, incursion into other FL and ignored Robert repeatedly telling him to descend. Bonin clearly verbalizes that he was stick back all along which tells us that it was a conscious decision. Not only was Bonin behind his airplane he was ignoring every fact being given to him. Startled is an over simplification of Bonin's mental state and warrants further consideration along with all the other failings. I leave it to the pysch experts to explain his fixation with stick back e.g. man with hammer syndrome, confirmation bias.

02:13:40 (Robert) Remonte... remonte... remonte... remonte...
Climb... climb... climb... climb...

02:13:40 (Bonin) Mais je suis à fond à cabrer depuis tout à l'heure!
But I've had the stick back the whole time!

At last, Bonin tells the others the crucial fact whose import he has so grievously failed to understand himself.

02:13:42 (Captain) Non, non, non... Ne remonte pas... non, non.
No, no, no... Don't climb... no, no.

02:13:43 (Robert) Alors descends... Alors, donne-moi les commandes... À moi les commandes!
Descend, then... Give me the controls... Give me the controls!

[john_tullamarine]

Chaps,

Tech Log seeks to discuss and debate technical issues - which, obviously, includes the human aspects of technical subjects.

Sometimes, some of us have very strong views on this and that.

However, we don't need to venture into personal commentary of an adverse nature where that is not materially pertinent to the underlying discussion - where this might be permitted, it will need to be justified objectively as being pertinent.

As always, the desired aim is to play the ball, not the players.

[DozyWannabe]

Was it a Titanic belief in the un-stallable nature of the airbus that the warning must be a glitch not even worthy of discussion?

A slight possibility exists, but I very much doubt it - for one thing, the fact that the aircraft can stall when in a degraded flight law is down in black and white in both training and ops materials that I know of. Also, the crews in the other similar incidents I mentioned earlier weren't flying FBW Airbus types, and the PF in those cases disregarded not only the Stall Warning and stick-shaker, but also their crewmates telling them they were in a stall!

@Turbine D:

I have a lot of respect for PJ2, and agree with the vast majority of what he writes. However what bothers me about writing off the consequences of what has recently been termed "startle response" as a
psychobabble notion created by non-pilots/non-aviation people
is that while the industry has - as he said - been dealing with scenarios such as this for a very long time, the fact remains that there is always room for improvement.

I was enjoying one of my periodic re-reads of "Fate Is The Hunter" the other week, and there was an embryonic version of the subject even then. Gann refers to it using the concepts of "fright" and "fear":

Fear and fright are two different things, the emotion of true fear requiring time for culture and preferably a period of helpless inactivity. Then fear breeds upon itself because it is a hermaphrodite capable of endless reproduction. Fear is a contagious disease, spreading from its first victim to others in the vicinity until it is powerful enough to take charge of a group, in which event it becomes panic.
Fear is the afterbirth of reason and calculation. It takes time to recuperate from fear.

Fright is only the percussion of fear. It snaps rather than rumbles and its explosion is instantaneous. Likewise, fright is self-destructive, being more of an instinctive physical reaction than it is an emotion. It hits, explodes, and may be gone as quickly, if it does not have time to ignite the keg of fear

(Emphasis mine)

If no less a legend of aviation than Gann had a handle on it many decades ago, then I'd venture to suggest not just that there may well be something in it, but that there may be some mileage in studying the effect properly.

What bugs me about how a lot of the hearsay around this case has gone down is that there's been a worrying groundswell of dismissive opinions from some quarters along the lines of: "Well, he was low-hours/automation-dependent/a 'magenta child', so he didn't really know how to fly". Which raises the worrying assumption on the part of people making such comments that they're dead certain that it would never happen to them. Part of the reason I've been banging on about the other incidents where captains with in excess of ten thousand hours and/or with a successful military career behind them have ended up doing more-or-less exactly the same thing is because people making those assumptions, in the face of these contrary facts, frankly scare the bejeezus out of me!

[roulishollandais]

@Machinbird,
Pardon. " As we know, the transcription of the acronym "PIO" has been modified and is still unfixed so long the solutions to avoid and recover from a variety of "oscillations" are still to fix and understand better. My propositions are leading too far of common definitions of theory of systems. I don't want to contest them (instability, gain, human operator transfer function). I have to write that clearer.:{

[gums]

Well, JT, I think we need to let this thead go on. Maybe re-label it and start over with existing posts, and that's your call.

There are a lot of techniques and personal war stories and lessons-learned and such for folks to learn from, huh?

We have had a diverse group of pilots and engineers here for almost 5 years. As a "light" pilot with an engineering degree, I was accepted by this current group to offer my lessons from an early FBW jet and to comment about other aspects of the aviation mistress we all served.

Seems all of us want/desire to help prevent accidents if all crews knew the data from the previous episodes to include crew techniques/actions, past problems of mechanical or electronic nature, and the beat goes on.

I vote to keep the thread going, but maybe re-label it and move to another forum if we have to.

On the road now to high country, owe some decent responses to some posts and will try to keep up with my morse code telegraph line from cabin to 'net connection. Carrier pigeons won't stay here, and chipmunks are unreliable.

[Machinbird]

Xcitation makes a telling observation about the progression of events in the AF447 cockpit.
IMHO the most perplexing of all the holes in the swiss cheese is the total absence of discussion given to the stall warnings by all 3 pilots. Was it a Titanic belief in the un-stallable nature of the airbus that the warning must be a glitch not even worthy of discussion? Have you ever had a wasp in your vehicle as you were driving? Darned distracting, wasn't it? In fact, this type hazard is so distracting that drivers experience a very high frequency of traffic accidents during these events because they cannot properly prioritize hazards and give their full attention to driving.

I have a personal theory (that is only a theory) that all 3 pilots were rapidly sent past their maximum sensory processing thresholds and thus they were filtering out all background noises. The development of this process in all 3 crewmembers seems to have followed a triggering sequence.

Bonin started the sequence by encountering roll PIO which dominated his full attention in a manner similar to the wasp phenomena that I mentioned at the beginning. His control of the aircraft was clearly deficient.

Bonin's flying greatly concerned Robert but since he felt constrained by the Captain's briefing, he did not give relief to his concerns by assuming control, but instead monitored the gent (big wasp) in the other seat who was effectively trying to kill him at the moment and concentrated on calling the Captain.

By the time Captain Dubois arrived on the flight deck, the situation had progressed to the point that the aircraft was not properly following the controls. Both the copilots loudly made exclamations that the aircraft was not under control. In effect, he had walked into a cockpit full of wasps. Apparently nothing in his background had prepared him for unraveling such a mess.

I know that things are never supposed to get this far out of hand in an airline cockpit, but it happened in real life. A triggering event followed by a triggered sequence is one way to explain how something like AF447 happened.

They never mentally heard the stall warning because there was no relief from the mental pressure of the event. The hazard kept increasing as the altitude unwound. There was no clear AHA moment.

[john_tullamarine]

gums,

The thread is far too interesting not to let it run its course ....

[alexd10]

By the time Captain Dubois arrived on the flight deck, the situation had progressed to the point that the aircraft was not properly following the controls. Both the copilots loudly made exclamations that the aircraft was not under control. In effect, he had walked into a cockpit full of wasps. Apparently nothing in his background had prepared him for unraveling such a mess.



And there is no certainty that even the SW was still on at the moment of his instrument scan.
And of course nobody want even to try to establish if at that time a determined (or yes, desperately) maneuver would allow recovery (no, not only full fwd stick , but rather a forced direct law + manual trim full ND at structural limit, even if that would made things to fly in the cabin, followed by a recovery at the g limit again).
After all many "impossible" situations were saved by pilots performing unstandard and untrained maneuvers. But yes - in a good situational awareness, which was not the case of AF447 - this plane set trap after trap to his crew, and of course they are only to be blamed for falling in ...

[Machinbird]

Did the Cpt Dubois experienced the SW or "inverted SW" only ?
The answer of course is that he only heard the inverted Stall Warning.The stall warningstopped as he entered the cockpit because the airspeed was too low for it to make sense (NCD).

Even if he heard it, it didn't make good sense to him either. It went into the too hard to understand right now category.

[PJ2]

Dozy, re:

However what bothers me about writing off the consequences of what has recently been termed "startle response" as a
Quote:
Originally Posted by PJ2
psychobabble notion created by non-pilots/non-aviation people

is that while the industry has - as he said - been dealing with scenarios such as this for a very long time, the fact remains that there is always room for improvement.I was well aware of fear/fright factors from the day one of my private licence and have felt such fright as all pilots do, a number of memorable times hence, from the early years right up to the year of my retirement. Such things are visceral and not subject to "improvement", (thank goodness). But physiological and psychological human responses which sublimate rational responses may be mitigated, as I went to some trouble to define, by thorough training, an abiding mentality of cockpit discipline when the going gets interesting, and recent developments borne of the results of such cockpit chaos and rapid loss of SA as we see in the AF447 cockpit; these developments are known as CRM and SOPs.

To me, the cockpit is where the buck stops; it is those hands and minds that govern everyone's lives on board. But that does not excuse or turn focus away from organizational circumstances which "planted the garden" for this failure.

But truthfully, really, there is some hindsight bias at work in this. In terms of this organization and the larger industry, was UAS on anyone's radar as a top training priority? No, it was not, even bearing in mind that much had changed since the two initiating accidents which brought the loss of airspeed information into the industry's 'consciousness' from which it created the UAS cockpit responses. AF had addressed the issue as early as 2006, providing training as to when and how to apply the UAS drill. As with other professions with similar responsibilities and authorities, the standard is constant learning and engagement over and well above the formal recurrent training schedule and requirements. I don't think that's too tough a standard at all but, again similar to other professions, some do "just come to work"...

We all know that thirty-one other crews experienced this event and for all of them it was a log-book entry, just as it should have been. I'm sure each one would verify an initial fright - in fact one would wonder about a pilot who did not exhibit that initial reaction. To be sure, there was "startle", (if that's the way some want to put it), in every one of these events - I can tell you that there was such during a subtle failure of airspeed info (blocked pitot - airspeed acting as altimeter) on a B767 over the Rockies one dirty night!). But that's what training, SOPs and CRM are for - to replace fear quickly and provide the road map forward which sublimates initial fright to engender disciplined action. It works - thousands of minor incidents like this occur in airliners every day and they are non-events.

Gann would also have known and intuitively appreciated that 230T of mass does not lose energy in a few seconds to the point of falling out of the sky; - there is a "pilot's (sixth) sense" regarding the airplane involved here which seems to have been missing in the crew combination of AF447. A number of things come to mind: - the lack of clear command-and-control structure left by the captain and engendered by the airline, (ie, the F/O in the left seat should have taken control but out of deference to structure, did not), the possibility that sublimation of the airplane's situation, (ie, "not-serious-but-requiring-attention"), a desire to "do something" which led to the instantaneous, (2-second) reaction by the PF to remembered-drills for UAS done right after takeoff in the sim instead of doing 'nothing' for the moment, (as I had suggested in June, 2009).

Stall warning or no, there is nothing unclear about buffet, an unwinding altimeter that is going through FL's once every three seconds and the inability to arrest a 10,000fpm rate of descent.

I think OG has nailed the PIO matter. I've tried it in the sim, (not just the UAS sim session). The reducing oscillations are to me a successful response to the very sensitive roll that the airplane has in roll-direct; the PF got it under control. The sustained and increasing pitch is significant enough to be separately-intentional and not a result of inadvertent input while getting the roll under control.

[BOAC]

Stall warning or no, there is nothing unclear about buffet, an unwinding altimeter that is going through FL's once every three seconds and the inability to arrest a 10,000fpm rate of descent. - this is the crux of the matter. We can talk about 'startle'/'fright'/PIOs/FBW/UAS training/QRHs etc etc until the cows come home, but as PJ characteristically has pointed out, there was a big 'hole' in comprehension throughout the cockpit, and I recall beating my gums (sorry Sir...:) ) over and over again about 'symptoms of the stall' in days of yore, and a low (or in the AB case, NCD) IAS, high nose attitude and ginormous rate of descent SHOULD have switched on the light. Surely it is not unreasonable to expect that at least one of the three would have noticed?

[DozyWannabe]

But physiological and psychological human responses which sublimate rational responses may be mitigated, as I went to some trouble to define, by thorough training, an abiding mentality of cockpit discipline when the going gets interesting, and recent developments borne of the results of such cockpit chaos and rapid loss of SA as we see in the AF447 cockpit; these developments are known as CRM and SOPs.

And that is *exactly* what I meant by "improvement", so please accept my apologies if that wasn't clear.

But that's what training, SOPs and CRM are for - to replace fear quickly and provide the road map forward which sublimates initial fright to engender disciplined action. It works - thousands of minor incidents like this occur in airliners every day and they are non-events.

Absolutely - and all I was saying was that there may be some possible solutions to plug the gaps where the situation still goes pear-shaped in spite of those things.

The sustained and increasing pitch is significant enough to be separately-intentional and not a result of inadvertent input while getting the roll under control.

I certainly agree that the pitch input was separate from the roll inputs, and always have. What I do question is whether the intention was conscious or sub-conscious.

[xcitation]

@DW
I certainly agree that the pitch input was separate from the roll inputs, and always have. What I do question is whether the intention was conscious or sub-conscious.
How do you reconcile the PF saying that he had been "stick back all the while" with a subconscious action. Surely his words explicitly state that PF intentionally stick backed as soon as he took control initiating the zoom climb.
IMHO one can question why he chose to stick back as a response to UAS however it is without doubt that it was intentional. I think an earlier poster suggested that his arm must have been aching with that continual pull pressure on the side stick. Maybe thats why he eased off momentarily a couple of times.

[DozyWannabe]

Fair point, but there's an important distinction between "all the while", as you put it, and the actual English translation which is:

But I’ve been at maxi nose-up for a while

(Final report Annexe 1 - p31)

"All the while" would imply that he's been pulling full stick back since the onset of AP disconnect, which does not tally with the DFDR trace. "For a while" implies that he has been consciously doing it for a period of time, but gives no clue as to when that period of time began.

Towards the end of the sequence, as the aircraft was descending in a mushy stall, it's fairly straightforward to reason why he may have decided to pull up. But at the beginning of the sequence, when the aircraft was still flying and the two F/Os had just discussed why they could not safely climb higher, it becomes a much more problematic issue to fathom out.

[Mr Optimistic]

Mental perception: clever sophisticated machines can fail in sophisticated ways . Crew convinced themselves that they were faced by something complicated and nothing should be taken at face value, including rushing noise, speed readings, altitude. Inverted stall warning treated accordingly.

[PJ2]

From the SSFDR traces, regarding the PF's sidestick position from initiation of the climb to impact:

http://www.smugmug.com/photos/i-GRhjsb6/0/XL/i-GRhjsb6-XL.jpg

[DozyWannabe]

Right, but to give it a bit more context:

http://i1088.photobucket.com/albums/i331/turricaned/fdr-munge.png

The descent begins around 02:11:17, shortly followed by the PF's emphatic back-stick to the stop after 02:11:30 (which has the unfortunate consequence of completing the THS's drive to the full nose-up position, fouling the pitot tubes and consequently rendering the Stall Warning intermittent). Though it was completely the wrong thing to do, I can understand the instinct to pull the nose up when the altimeter begins to wind down.

What I have more trouble understanding is the motivation behind pulling the nose up past half-stick deflection around 02:10:09 (i.e. at AP disconnect), when the PF has just been explaining to the PNF why they are unable to safely climb to a higher flight level.

[PJ2]

Dozy;

(which has the unfortunate consequence of completing the THS's drive to the full nose-up position, fouling the pitot tubes and consequently rendering the Stall Warning intermittent)The elevator had sufficient authority to get the nose down - it was never stalled, (discussed at length in The Threads). Had the stick been held forward the aircraft would have recovered, while the THS was returning to it's cruise position, (that's the behaviour we saw in the sim).
Though it was completely the wrong thing to do, I can understand the instinct to pull the nose up when the altimeter begins to wind down.Yes, it is instinctual and must be, to the extent possible, "trained out". Difficult though - better to avoid such a requirement altogether as such instinct has killed at least two other crews, (DC8 - test flight, B727 - placement flight) that we know of. It may have been a factor in the Trans-Canada-Airlines DC8 crash at St. Therese in the mid-60's.
What I have more trouble understanding is the motivation behind pulling the nose up past half-stick deflection around 02:10:09 (i.e. at AP disconnect), when the PF has just been explaining to the PNF why they are unable to safely climb to a higher flight level.
It isn't productive to wonder because, although we may imagine all kinds, I doubt if there is a specific reason. By this time the PF was lost/confused but unwilling to yield control to the more experienced man, who never pressed the take-over button for 15" or whatever it takes to lock the other sidestick out.

[DozyWannabe]

The elevator had sufficient authority to get the nose down - it was never stalled ... Had the stick been held forward the aircraft would have recovered, while the THS was returning to it's cruise position, (that's the behaviour we saw in the sim).

Right, and it's what we saw in the sim as well (my summary on the megathread is linked here):
http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-85.html#post6793521

The caveat was that it took between 5 to 8 seconds of constant full nose-down on the sidestick for the THS to return to a "normal" position. Release to pitch-neutral too early and you run the risk of the THS causing the aircraft to pitch up again. Of course, if you're certain of what you're doing that's no problem - but if the environment is as disjointed as the AF447 flight deck seems to have been, I'd argue it'd take quite a bit of nerve to follow through.

Yes, it is instinctual and must be, to the extent possible, "trained out".

Right again - I guess the angle I'm coming from is asking whether there may be more consistently effective methods of training it out than those we have now. And while it may not be productive to merely wonder, as you say, the idea that 80% of a random sampling of pilots instinctively pulled up when startled by a Stall Warning - i.e. the effect was such that it completely negated their training - worries me greatly. It also can't help but make me think we're missing something.

[jcjeant]

The warning "Stall" seems to invite some pilots to put the stick on their stomach ... So replace this "Stall" warning by another like "Noze down"
Maybe more pilots will better understand ...... if any
Simple problem .. simple solution :)

[roulishollandais]

Some basic definitions and references about control theory, stability, oscillation, gain and PID,etc.

Oscillation - Wikipedia, the free encyclopedia (http://en.m.wikipedia.org/wiki/Oscillation)

Control theory - Wikipedia, the free encyclopedia (http://en.m.wikipedia.org/wiki/Control_theory)

PID controller - Wikipedia, the free encyclopedia (http://en.m.wikipedia.org/wiki/PID_controller)

[noske]

What I have more trouble understanding is the motivation behind pulling the nose up past half-stick deflection around 02:10:09 (i.e. at AP disconnect), when the PF has just been explaining to the PNF why they are unable to safely climb to a higher flight level.

You seem so sure that the PF would have had no reason to climb intentionally. I'm not so sure.

At 01:52:23, when he pointed out to the Captain: "You see the REC MAX it’s changed to three seventy five", the Captain's only reaction was to start making preparations for his rest break. Later, when he said to the PNF in the briefing at 02:00:33 "So what we have is some REC MAX a little too low to get to three seven", I can imagine him thinking "...and this doesn't seem to bother our stubborn old man at all."

From the report (2.1.1.2):
...the PF wanted to change flight level and fly above the cloud cover, while recognising that it was not possible for the moment to climb two levels. He made several allusions or suggestions on the flight levels and the temperature from 1 h 35 min 20 onwards. He even considered requesting a non-standard level 360. His various interventions in the minutes that preceded the autopilot disconnection showed a real preoccupation, beyond the simple awareness of an operational risk. Some anxiety was noticeable in his insistence.

[PJ2]

Hi Dozy;
Re,And while it may not be productive to merely wonder, as you say, the idea that 80% of a random sampling of pilots instinctively pulled up when startled by a Stall WarningSorry, I may be gradually losing it but where do I say, "...the idea that 80% of a random sampling...", etc? I don't believe I'd say such a thing because I don't believe the statement to be true in the first place! ;-)

[DozyWannabe]

Sorry - ambiguous wording. "as you say" refers to your assertion that "It isn't productive to wonder".

You may not believe the 80% figure, but the stat and its source are very real and discussed earlier in the thread (Tarom A300 over Paris Orly).

[roulishollandais]

I agree with you
PJ2 and don't believe to the existence of such an experiment.@DozyWanabee
1. It has been said again and again that training was a major factor in AF447. I don't remember that inexperience has been pointed as such a point. Why don't Airlines maintain the level from skilled pilots like these Vétérans ?

2. You know that math was my first learning. In that immense matter, I used "some" time in stats ! Real stats. Not what we are used to read in magazines, because stats are not very pleasant to understand nor to read... And no aviation investigation wants to give you a pleasant reading ! or a complete demonstration.

Please watch, about Airliners stall, on one hand we are reading that test pilots don't stall airlines, on the other hand we should accept that airlines pilots (likeTarom) should have done an experimentation with 80% pilots pulling the stick at any startle factor... Where are these experimentations ? they don't exist !

[Machinbird]

Well from an informal sampling of USN carrier pilots, 99.999% will reduce angle of attack when receiving a stall warning and the ones that don't are generally facing an imminent collision with something solid and are trying to at least get the cockpit above the solid object before impact.:}

[PJ2]

Ah, understand thanks. I am indeed losing it or over-interpreting...!

I read the posts earlier in the thread earlier, (and again, now) - I was looking at the "80%" figure more broadly and not in the rare specific cases cited. It's not a matter of belief, the stats are indeed there, (I was thinking training scenarios, etc).

While the sample rate is to small (Tarom, Colgan, Thomson, Turkish...are there others?) to take this statistically-seriously, I could understand the notion that it, (pulling up and in some cases not adding power), at first warning of a stall, should never occur in such a high-risk event does take us beyond statistics into a mandate to do something.

In this then, I don't think it is possible to over-train.

I believe in Gladwell's notions, (Outliers). I play an instrument which is both a cognitive and muscle-memory activity and the only way to play accurately and fast is to practise, practise, practise.

Both cognitive response time and muscle memory improve dramatically and, (if one is performing in public, which I certainly do not!), reduces performance anxiety, and startle tremendously regardless of whether it is an airplane, typing on a keyboard, playing the piano or reciting/speaking text from memory. The mind-and-muscles "go to the right place", to loosely describe it.

I know you and many here know this already - it isn't new, though Gladwell has put a refreshing interpretation on it. Here, not only was there not a correct response, (or a response to incorrectly-perceived cues) but no concept of what was about to rapidly happen to the aircraft's energy in a sustained climb. There seemed no concept or awareness of an airplane's physical state or environment. It should not be possible to get into the cockpit of a transport aircraft absent these basics.

In the light of AF447 especially, but also in view of the "80%" perspective, I wonder what our regulators consider "stall practice" these days?

I know that in Canada, once one has been initially certified for the airplane, there is no requirement whatsoever to demonstrate approach-to-the-stall or stall recovery in fly-by-wire aircraft. I have no idea what the justification is for this because it seems to imbue FBW technology with some form of magic when it's just another way of moving the flight controls. I suppose they're thinking of the Airbus protections but we all know now that a more sophisticated approach to such training needs to be done. What do the JARS have to say?

[DozyWannabe]

and don't believe to the existence of such an experiment.

@galaxy flier:

That figure came from this report on YR-LCA - an A300 on approach to Orly airport in 1994:

YR-LCA (http://www.bea.aero/docspa/1994/yr-a940924a/htm/yr-a940924a.htm)

(Use your browser's "Find" to look for the relevant section with '80%')

Also, PDF version in English: http://www.bea.aero/docspa/1994/yr-a940924a/pdf/yr-a940924a.pdf (Page 30, Para. 5)

and French : http://www.bea.aero/docspa/1994/yr-a940924/pdf/yr-a940924.pdf (Page 29, Para. 7)

The document exists, and if you believe there was no experiment to glean those statistics, then you're effectively accusing the BEA of making the figure up - a serious allegation!

[EDIT : NB. My above comment is directed only at roulis. Cheers for the clarification, PJ2!]

[xcitation]

@Noske

Thank you for setting the context prior to AP disconnect of PF anxiety and a desire to climb above the weather. So apparently the PF was already biased to climb before AP disconnect. In stress such bias can be amplified.
That said why would he not verbalize his action to increase flight level to his colleague when he initiated the zoom climb. My own view is that it was a conscious action and a failure to verbalize/communicate to PNF rather than a subconscious.

[PJ2]

xcitation;

Re,
My own view is that it was a conscious action and a failure to verbalize/communicate to PNF rather than a subconscious.
Yes, I think so. This is consistent with all cockpit behaviour noted by the BEA - absence of SOPs and CRM at critical junctures where it counted and likely would have made a difference in the outcome.

Anyway, there is little to re-argue/re-hash that isn't in The Threads, so returning to lurking while awaiting something new and interesting.

[DozyWannabe]

That said why would he not verbalize his action to increase flight level to his colleague when he initiated the zoom climb. My own view is that it was a conscious action and a failure to verbalize/communicate to PNF rather than a subconscious.
I'm not denying it's a possibility - but on the other hand, if the control input was an entirely conscious move to get to a higher FL, why did he not level out at a sensible point and instead continue to drag the aircraft up towards "coffin corner"?

[jcjeant]

Paradoxically .... unconscious can do things consciously !

[xcitation]

@DW
why did he not level out at a sensible point and instead continue to drag the aircraft up towards "coffin corner"?
Excellent point. I think this is where bias comes in. When all you have in your hand is a hammer everything looks like a nail. To him he had pre-occupied his mind with getting higher to fix the problem. Then after AP disconnect he got confirmation bias coupled with an endorphin rush. I think this is the gremlin that we referred to as startled. As a pilot it is critical to understand that the brains perception can become biased during stress. This is effect amplified by modern highly automated cockpits.

[DozyWannabe]

While I certainly wouldn't disregard the possibility noske brought up, I had a quick look back at the report because I was sure I was forgetting something - which turned out to be this:

The relief crew did in fact inherit some decisions to make. From 2 h 01, the PF mentioned the subject of the ITCZ, turbulence and the choice of flight level in his briefing to the co-pilot who joined him as relief for the Captain. From 2 h 04 to 2 h 08, after the Captain’s departure, the two co-pilots discussed the ITCZ again. The PF repeated his idea of climbing to level 360, without doing so. Acknowledging this non-solution, he warned the cabin personnel of imminent turbulence. After changing the gain on the weather radar from “calibrated” to “max”, the PNF then suggested as of 2 h 08 min 03 a route alteration, which the PF willingly executed.

Therefore there exists the possibility that the "problem" as you describe it - namely the weather/turbulence situation and how to avoid it, may have been considered as solved in the mind of the PF with the PNF's lateral course change.

[Machinbird]

Therefore there exists the possibility that the "problem" as you describe it - namely the weather/turbulence situation and how to avoid it, may have been considered as solved in the mind of the PF with the PNF's lateral course change. Solved? I don't think I'd give that interpretation a very high probability.

Crews usually consult on the best route through weather. The process has enough variability that you would never consider a weather problem solved until it is behind you. Best you can hope for is to achieve the least hazardous route.

[alexd10]

Solved? I don't think I'd give that interpretation a very high probability.

For Gods'sake Sir, I think it's possible that the "overpedantic " gentlemen had a slip of mind with "solved" and would better used "dealed by..' or "treated by..."

[Machinbird]

NOT semantics. This relates to the mind state of the person flying. While picking your way through weather, if the person flying consideres that an instantaneous choosing of the apparent best heading has completely taken care of his weather problem and he can relax and think about other things, then he probably doesn't even belong at the controls.:mad:

[alexd10]

We can therefore consider in addition to other possible causes for the persistence of pulling (and the uncommon pitch of 12-15° followed), the initial intention to avoid the storm by climbing, pursued simply omitting to move the throttles and to let the other guy know what he intended...

[DozyWannabe]

@M'bird:

Where do I say that "instantaneous choosing of the apparent best heading has completely taken care of his weather problem and he can relax and think about other things", or words to that effect?

Maybe it's because I've been reading Dr. Al Diehl's book on human factors recently, but I'm talking more from a psychological perspective than a practical/piloting one. Of course a minor course correction isn't going to completely solve the weather problem - and I doubt the PF thought so, but generally I find that people tend to get their stress levels elevated more when they perceive that there's a problem and nothing is being done about it, and while it doesn't exactly go away, it does tend to subside somewhat when they recognise that attention is at least being paid to solving the problem.

Incidentally, I completely recognise what you're saying about USN carrier pilots, but I think sending every trainee airline pilot to go shoot carrier landings before giving them their ATPL is probably overkill... :}

[jcjeant]

Since this discussion seems to be moving in all directions and more about .. we can add .. some of which appear to be an unimportant detail ... but ..
In its final report, the BEA said he has told Airbus to make a simulation to reproduce the flight controls during the accident to compare with the FDR data
This is to forget something important from the standpoint justice
Airbus is one of the accused in the trial and was already when the simulation was requested
This is called "be judge and jury" and it is not allowed under French law
This simulation should have been made ​​by an independent body
To follow at the trial !

[DozyWannabe]

But the report is not part of the judicial process, merely a finding of fact. Given that EADS has the best tools for providing the simulation requested, it's simply common sense to ask them to produce the simulation, and it's a very simple matter to compare the control inputs of the simulation to ensure that they match the actual DFDR data.

Non-issue as far as I'm concerned.

[jcjeant]

Non-issue as far as I'm concernedFor me .. the same ..as I'm not concerned .. :)
I think .. it will be a issue ... for those concerned
it's simply common sense to ask them to produce the simulation
It's a big gap between common sens and laws
To verify in some years

[DozyWannabe]

I think .. it will be a issue ... for those concerned

It's a big gap between common sens and laws
To verify in some years

OK, let's get this straight. The BEA report is not a legal document, and the accident investigation is completely outside of the legal process. EADS (Airbus) are in possession of the simulator which can fulfil the request - no other entity has tools which are anything like as accurate. The simulation would be run with BEA people present in order to verify the accuracy of the inputs to the simulation, as well as to study the simulated responses. There is nothing untoward about this, and I'm fairly certain this process is pretty much identical in the US with Boeing. The manufacturers have to be the ones to run the simulation because they are the only entities in possession of simulation tools with the required accuracy.

If the SNPL legal team want to argue the point, then they'll have to take it up during the court case(s) when the BEA report is entered into evidence - but they'd have to have a very strong case of presumed malfeasance first. Of course, they could also send their own guys up to the EADS labs to verify the simulation for themselves...

[roulishollandais]

The BEA report is not a legal documentICAO, Annex 13, BEA reports are not "legal" documents ???? What is legality for you ?:mad: Only A docs ????

[DozyWannabe]

I mean that the report is not part of the criminal justice process in and of itself (though the report will be entered into evidence in any court cases related to the accident).

And what are "A docs"?

[jcjeant]

The BEA report is a legal document
Without worrying about international law and taking into account only the French laws we can say that:
The French state has requested (through the Minister of Transport) to the BEA to conduct the accident investigation
BEA is an agency of the Ministry of Transport
This report will be produced at trial (how could it be otherwise, since this report accurately describes the accident and provide related documents)
This is a common thing (see last trial dated .. the Concorde)
This process is also an opportunity to examine whether the BEA has followed the law to conduct its investigation .. because the state is obliged to respect the laws
As I write before ... wait some years for the trial ...

[roulishollandais]

A Judge is absolutely independant. He is not allowed to interfer in the investigations, both of BEA and experts and counter-experts. The BEA is a public document according the Annex 13. Experts and counter-experts are requested by some parts or Justice (Prosecutor) but decided by Justice. The Court uses ALL these informations.

[roulishollandais]

ICAO clearly stipulates that aviation accident reports shall not be used for legal proceedingsICAO never asked to victims, judges, aso to be idiot and unable to read or -worse- to think that Agencies lie and create fantasy with debris, logic and evidence. And if they do that they are guilty. We are speaking of civil aviation and general aviation.

The law is not math or pure logic applying silogisms. Complexity of real life is concerned. Something that most people forget with law is the absolute necessity of GOOD FAITH. That is true in national and international law.

And they are always limits in every thing. The limit in ICAO rules are there to protect souverainty of States, and protection of property, not to hide the facts and proofs.

How do you imagine the two trials in Colmar (Habsheim and Sainte-Odile) could exist applying strictly the sentence you were quoting out of context ? The first day of the trial the Army of Lawyers should have requested to stop the trial. But they did not that.
In military life where state safety is concerned, mostly the choice of Army is not to protect their failures not to deny reports.

We may have regrets but time of secrets is gone. (Secrets still exist during a short time, sometimes very short time, not more).Judge read the BEA reports and are always allowed to ask the answered question during the trial and to experts who read the BEA report, etc.

[jcjeant]

Concorde trial (minutes)
Sorry it's in french .. of course :)
mars « 2010 « Procès du crash du CONCORDE (http://procesconcorde.fenvac.org/?m=201003)
BEA report is examined
BEA chairman is interrogated about some details of the BEA report

[roulishollandais]

Thank you jcjeant. Good example of what is called "Droit positif" (don't know the English word)

[DozyWannabe]

But that doesn't stop the reports from being entered into evidence *as* an independent assessment. Which is fair and right.

Personally I don't think criminal courts have any place in this type of proceeding (unless something is obviously untoward), but what do I know?

[roulishollandais]

The Court knows. So a Trial is the best thing to do if people died or/and the plane is destroyed or disappeared and/or damage on ground to examine if criminal negligence or fault was the cause of these facts.

[DozyWannabe]

To be perfectly honest, it seems that the only thing a significant number of the French court cases have done is allow the SNPL to make slanderous accusations in the press against Airbus and the BEA. Generally, I think bringing the legal system into it without clear evidence of criminal wrongdoing seems to make things worse rather than better - though there are exceptions (the Royal Commission into the crash of TE901 into Mt. Erebus being a good example).

[Turbine D]

Dozy,

I think you have to accept the fact "Droit positif" or Substantive law is the major legal method used throughout the world, the exception being, former English colonies where Common Law (Procedural law) is used. Even in the United States, it is a mixed bag in some States (Louisiana and other Southwestern States) that were not so influenced by the English colonization, some Common Law and some Substantive law are used to this day in those States. In either law, the objective is the same, only the methodology to reach the objective differs, the objective being justice. If you look at Continental Europe, Substantive law rules, although regulations vary from one country to the next.

I believe in France, Substantive law is used to determine whether a crime or tort (negligence for example) has been committed and to define what charges may apply and decide whether the evidence supports the charges. In other words, specific facts need to be proven true in order to convict someone or an organization of a crime or a tort. In some ways, it is like what a grand jury is charged to determine in the United States, except in France a judge is selected to make the determination.

So it would seem reasonable that all evidence gathered either by the French Court or by independent sources (BEA and the BEA report) would be examined and those persons or organizations connected to the evidence interviewed to clarify the written word.

At this point in time, I am not sure it has been decided what charges apply in the AF447 legal proceedings. I do know that a United States Court determined that the families of two US citizens who perished in the accident could not sue in the US Court system for damages, instead the Court decided the French legal system was perfectly adequate to make this determination on their behalf.

[DozyWannabe]

Absolutely TD, and I'm in complete agreement with you. I just think that based on historical events, the point at which accident investigation and the legal system intersects must be navigated extremely carefully, is all. :ok:

[DozyWannabe]

@roulis:

The press pretty much anywhere write what they want - the only issue is that their agenda is to maximise sales of their paper/ads on their TV channel/hits on their site and will print whatever sounds the most "controversial" in order to do so. This tends to mean that accidents are frequently misunderstood in the public mind long after the dust has settled.

[jcjeant]

@Winnerhofer
Thank you ...

[roulishollandais]

ICAO clearly stipulates that aviation accident reports shall not be used for legal proceedings! It is a fundamental point that the accident report such as this can not be used in court under any circumstances because of the chill that would have on the fact-finding process!
see above post 199 in french
We see in that long document in French from the French Justice Ministery that coordination, cooperation, sharing all informations is perfect and rapid between BEA, Justice and experts. So the ICAO ad is clearly not conform to reality, or perhaps we misunderstand the world "used" in that sentence ;) !

[roulishollandais]

@roulis:

The press pretty much anywhere write what they want - the only issue is that their agenda is to maximise sales of their paper/ads on their TV channel/hitson their site and will print whatever sounds the most "controversial" in order to do so. This tends to mean that accidents are frequently misunderstood in the public mind long after the dust has settled.You are probably the only who trusts in the french newspapers. People like to imagine the world to increase their fears. Perhaps they are a little suicidal too today : often when we had to delay one or two minutes the take-off due to big storm reaching the runway before us, the cabin crew went to inform us that some paxes where angry to be late, despite information was given on the Public-adress... :O

[DozyWannabe]

Roulis, my friend, I trust absolutely *no* newspapers in the world at all! :ok:

[DozyWannabe]

@Winnerhofer:

Your link is to the front page of the blog rather than the specific post. I think this is what you're after:
AF 447 : avant le non-lieu : Les dossiers noirs du transport aérien (http://henrimarnetcornus.20minutes-blogs.fr/archive/2014/06/25/af-447-avant-le-non-lieu-901150.html)

M. Marnet-Cornus does not specify where this information is coming from as far as I can see. And while I agree with his point that the role played by the apparent slowness in replacing the AA pitot tubes should not be ignored, I can also see why making a strong case against Airbus would be difficult in that regard. Because while the manner of their mandate to replace the pitot tubes left the specifics regarding timing up to the airlines concerned, the fact remains that they did mandate the change and provided materials to the airlines which constituted a workaround for the problem in the interim.

However, this still potentially leaves AF open to answer questions, as it was their timeline for applying the Service Bulletin that meant that particular aircraft did not have the fix applied when it encountered the conditions which blocked the pitot tubes and ultimately crashed.

[jcjeant]

M. Marnet-Cornus does not specify where this information is coming from as far as I can see
Maybe he do as journalists:
Source protection

[llagonne66]

Well, that's not what is written in the final report pages 142-143.
EASA (not Airbus, not DGAC) has decided in March 2009 that: QUOTE
at this stage the situation did not mean that a change of Pitot probes on the A 330/340 fleet had to be made mandatory.
UNQUOTE
It means that the status of the SB stayed at the "recommended" level.
That may be a good reason for the Investigative Magistrate not to pursue Airbus.

[DozyWannabe]

Right, but manufacturers can themselves enforce compliance without needing to involve authorities by including the SB in revised maintenance manuals or instructions for continued airworthiness (ICA). Not sure what the precise status was in this case, but it's fairly clear that Airbus wanted the work done.

[llagonne66]

That's why the SB was "recommended".
That was the farthest the manufacturer could have gone in this situation.
Next level is "mandatory" but then the SB is covered by an AD and it's clearly outside the manufacturer's scope.

[roulishollandais]

Are experts and lawyers managing a trial decision like "Everyone is culprit, so nobody is culprit" (comment of Albert Ducrocq after the Ariane 501 launch crash report) ?

[DozyWannabe]

Not really, I think it's just that any lawyer (for plaintiff, prosecution or defence) will usually only want to argue the strongest possible case - and in this event the case against Airbus isn't as strong as the case against the airline and regulator.

[roulishollandais]

Not sure of that scenario. Other possibilities exist.
Wait and see.

[DozyWannabe]

@Winnerhofer:

Any chance of a summary in English for those of us who are, lamentably, not Francophone? :ok:

[DozyWannabe]

On point 6, the reporter must be unaware that the BEA are compelled to be "neutral" by their own remit. Like other investigative agencies, they can recommend remedies but cannot enforce. And as with other "civil service" agencies like the UK AAIB (but unlike the US NTSB), their remit forbids them from apportioning specific responsibility.

[alexd10]

Maybe they should , but sure the increase is offset by the volume discount, so probably they pay less than smaller and "safer" operators....:(

[jcjeant]

Will AF be alone in the dock?

Catastrophe Rio-Paris: fin de l'enquête (http://www.lefigaro.fr/flash-actu/2014/07/02/97001-20140702FILWWW00221-catastrophe-rio-paris-fin-de-l-enquete.php)

Les juges d'instruction "nous ont très fortement laissé entendre qu'Air France et Airbus", mis en examen pour homicides involontaires, "seront renvoyés en correctionnelle, à tel point que c'est pour nous une certitude", a affirmé aux journalistes Me Alain Jakubowicz, l'un des avocats de l'association Entraide et solidarité AF447

The judges have strongly suggested that Air France and Airbus,will be indicted for manslaughter, it is a certainty for us," he told reporters Alain Jakubowicz, a lawyer for the Mutual Aid Association and solidarity AF447

[DozyWannabe]

Seeing as a significant chunk of the issues raised by the accident in terms of aviation safety are already being addressed (e.g. stall recovery training), I doubt any delay in the legal process will make a great deal of difference.

I'd also be very wary of making assumptions based on how the legal representatives of the various parties are briefing the media - because they're always going to be somewhat biased in favour of the preferred outcome for those they are representing.

[jcjeant]

Seeing as a significant chunk of the issues raised by the accident in terms of aviation safety are already being addressed (e.g. stall recovery training), I doubt any delay in the legal process will make a great deal of difference.The trial will be highlighting the issues of security the time of the accident .. and not those present and the trial will try to determine the responsibilities of each and others on the lack of security .. if any
That's the duty of the trial
Aviation safety is the job of the regulators

[xcitation]

Is evidence in the trial made available to the public or is it all confidentail?
For example if the CVR is admitted as evidence would they release the recording to the public or if they went into the background of the 3 pilots then it would be made public.

[jcjeant]

Is evidence in the trial made available to the public or is it all confidentail?Nothing confidential in this kind of trial .. until the judge estimate that something must be examined behind closed doors (most unlikely) at the request of any partie
CVR (transcript) can be requested and produced in the trial
Actual CVR recording (voice) will be not requested unless it's a VERY good reason (full argumented) by the judge ( one case already in a trial in Canada concerning ATC recording if my memory don't fail :) )

[DozyWannabe]

Again, M. Marnet-Cornus is not exactly an unbiased source. I'm still bewildered as to how he expects the BEA to have forced a move from the DGAC when it is impossible for them to do so (their remit only allows them to make recommendations - they cannot force changes).

[roulishollandais]

"France is an old country of Law". She remained cautious to accept
1. The offense of endangering the lives of others
2. Criminal liability of legal persons
3. Crimes committed by the government, Justice, regulators or Elected
4. Crimes recognized by international law
5. Reparation at level of actual damage.
6. Technical negligence to do the best possible at the moment to avoid fatal "errors" and massive deaths, injuries, losses

Consequently, even these points entering the codes in the last decades, the French Judges fear for their careers if they apply the sanctions provided by Law.

At the time of the communication and win-win principles, combinazione with the powerful outweighs the notions of good and evil, to the detriment of victims.

The appeal of Ste Odile showed that DGAC and military air controller lawyers have effectively relied more administrative pathes. It seems to me that the current choice anticipate such a defense, rather than the funds and aviation safety.

[roulishollandais]

Is the lawyer Daniel Soulez-Larivière?

[Clandestino]

I'm still bewildered as to how he expects the BEA to have forced a move from the DGACThe same way the AF447 thread got into its 12th incarnation - by liberal application of wishful thinking.

[DozyWannabe]

If there's one bone bigger than the other to pick is just who the hell kept on approving Thales' Pitots??

Because, in a regulatory sense, the Thales AA pitot tube was still technically fit for purpose. Have a look at this article from 2009:

Airbus backs overhaul of pitot icing certification standards - 12/13/2009 - Flight Global (http://www.flightglobal.com/news/articles/airbus-backs-overhaul-of-pitot-icing-certification-standards-336220/)

[EASA] opened a consultation in August on revising ETSO C16 - which was based on decades-old criteria - to align it with the US Federal Aviation Administration's more modern standard TSO C16a.

But Airbus ... has expressed "significant concerns" about the adoption of the updated requirements.

It claims that the icing conditions laid out in the USA standard are "not sufficiently conservative" and that icing test requirements are lower than the airframer's own.

Airbus says the [FAA TSO C16a] standard does not require probes to be tested in ice-crystal or mixed-phase icing, despite their sensitivity to these conditions.

So while EASA's certification criteria were less up-to-date than the FAA's, it would appear that even the later FAA standard does not take this form of icing into account, and consequently the Thales AA pitot probe would have passed certification in the US too.

Weren't 40+ incidents enough?

Closer to 30, and not all of them involved the Thales probes, the Goodrich models could still have issues if the conditions were severe enough. Avoiding bad weather in an aircraft is not just for the sake of not wanting a bumpy ride!

Ultimately, prior to this accident the aviation industry did not consider temporary loss of airspeed indication to be a significant threat - just set pitch and power if necessary and the aircraft will take care of itself until the blockage clears.

In a purely technical sense, this aircraft did not crash because of the blocked pitot probes, it crashed because the instinctive reaction of the pilot flying was inappropriate - and this was not caught and corrected by the rest of the flight crew.

PS: Winnerhofer, you seem to have an intense personal animosity towards the French authorities - how come?

[john_tullamarine]

Folks, I appreciate that feelings can run strong and that this topic, in particular, is of great interest to us all.

However, it is not our place here to have discussion extending to an aggressive and, potentially, legally risky level.

Please consider posts carefully lest I be forced to wield a sword.

[DozyWannabe]

It'd be nice to have a bit of a summary in English, I must say.

Correct me if I'm wrong, but as far as I can make out, the author of the slide set seems to be arguing that prior incidents warranted more action from the DGAC earlier, that the BEA should have made a public report on the issue and that AF and Airbus should have forced the pitot tube replacement earlier.

All these things are definitely worthy of consideration with the benefit of 20/20 hindsight, but it doesn't take into account the point I repeated earlier, namely:

...the aviation industry did not consider temporary loss of airspeed indication to be a significant threat - just set pitch and power ... and the aircraft will take care of itself until the blockage clears

The slide set itself quotes the FSF as saying there were 300 accidents and incidents involving flight instrumentation issues from 1989-1999. The Thales AA probes were only offered as an optional fit to the A330/340 from 1999 onwards I believe, so the author is misrepresenting a more general statement as something specific to this case - i.e. none of those 300-odd incidents involved the Thales AA probe.

[DozyWannabe]

(you know the references they were already posted many time)

Actually I don't remember the specifics. Could you dig the references up for me?

What I'm pretty sure of is that this is the only commercial accident in the last 25 years involving loss of/faulty instrument indications where airspeed was the only thing lost. Others involved additional factors such as false overspeed warnings (and consequent AP pitch-up), or faulty altimeter readings.

So it's to know who is in charge of the regulation of air safety ... the aviation industry or the regulators ?

The regulators are *part of* the industry.

[EDIT : Winnerhofer:

First, I'd recommend that you don't post links directly to MS Office documents (such as PowerPoint files), as they have been known to contain malware - see if you can find a web-enabled link in future if you can.

I did upload it to my Google Drive and had a look, and as far as I can tell it's yet more SNPL nonsense. The author of the PowerPoint is basically arguing that the crew were handed what he calls "latent conditions" specifically by Airbus, AF and the French authorities. He links an unrelated 2002 piece in which the aircraft is expected to leave the flight envelope to the AF447 conditions in which it was not. It left the flight envelope because of the actions of the pilot flying.

He also infers that:
- The BEA should have investigated earlier incidents because the AF crew called a Mayday in one of them. As far as I'm aware a Mayday call does not automatically trigger an investigation by any investigation agency I know of.
- The BFU and NTSB recommendations applied to the Thales AA pitot probes alone, when they did not.
- The ETSO C16 standard was expected to be replaced with one which included mixed conditions and ice crystals, which it was not (see my post #232)

[DozyWannabe]

Le décrochage "revenir aux incidences de vol" - Ministère du Développement durable (http://www.developpement-durable.gouv.fr/Le-decrochage-revenir-aux.html)

It's a bit hard to follow you if you just post links without commentary of your own. I'm wondering why you've stopped using your own words.

The "approach to stall" focus as opposed to "stall recovery" prior to AF447 was a global issue, not just one restricted to France.

[jcjeant]

...the aviation industry did not consider temporary loss of airspeed indication to be a significant threat
Actually I don't remember the specifics. Could you dig the references up for me?
January 1999: The BFU recommends changing certification standards Pitot probes
(Annex 13).
December 2002: The FAA mandates the replacement of the Rosemount probe probes
Goodrich and Thales AA indicating the possibility of leaving the flight domain and that is the answer to an "unsafe condition" (Annex 39)
January 2005: Thales launches the project "ADELINE" (Appendix 5). Actual air data equipment is Composed of a wide number of individual probes and pressure sensors. This equipment Delivers vital parameters
for the safety of the aircraft's flight:
such as air speed, angle of attack and altitude. The loss of these
data can cause aircraft crashes Especially in case of probe icing.

[DozyWannabe]

As far as I can tell, project ADELINE was actually a joint commercial/academic research programme to find possible *successors* to the existing pitot-static/vane technology. The fact that the online references to the project seem to have disappeared over the last few years seems to indicate that they couldn't find one that was practical at this stage.

[jcjeant]

research programme to find possible *successors* to the existing pitot-static/vane technology

Yes indeed but the important point in regard of this:
...the aviation industry did not consider temporary loss of airspeed indication to be a significant threat
is this (bold)
January 2005: Thales launches the project "ADELINE" (Appendix 5). Actual air data equipment is Composed of a wide number of individual probes and pressure sensors. This equipment Delivers vital parameters
for the safety of the aircraft's flight:
such as air speed, angle of attack and altitude. The loss of these
data can cause aircraft crashes Especially in case of probe icing.
And
December 2002: The FAA mandates the replacement of the Rosemount probe probes
Goodrich and Thales FAA indicating the possibility of leaving the flight domain and that is the answer to an "unsafe condition" (Annex 39)
So in fact the aviation industry (and regulators .. part of it) considered the temporary loss of airspeed like a threat IMHO

[DozyWannabe]

@jcj:

I think the qualifying words are "The loss of *these* data" - meaning more than one of them [EDIT : and as if789 correctly points out below - permanently], an example of which was the Aeroperu 603 accident. Or a situation where loss of one has knock-on effects (like Birgenair 301). As long as you're (relatively) straight and level, temporary loss of airspeed data can be easily overcome by using pitch-and-power, which is the reason smaller aircraft which don't have any redundancy in the pitot-static system can still pass airworthiness requirements.

In short - the temporary loss of airspeed indication *alone* was not considered a threat because there were long tried-and-tested workarounds.

Regarding the FAA's point on replacing the Rosemount units, I'd like to see the original document if anyone has a link handy. They may have been thinking along the lines of Birgenair, where a blocked pitot tube on one side caused the automation to pitch the aircraft up to the AP pitch/AoA limit due to a false overspeed condition. Even in that case the aircraft only departed controlled flight when the PF (Captain) pulled the throttles back to further reduce speed and immediately put the AoA into the stall regime.

The Airbus systems automatically disengage autoflight if the data from the three pitot sensors disagree, so a similar situation would not happen there.

[infrequentflyer789]

{ been away for while, come back and found there is still a 447 thread -
but, unexpectedly, with interesting and new information }


Yes indeed but the important point in regard of this:
...the aviation industry did not consider temporary loss of airspeed indication to be a significant threat

is this (bold)

The loss of these
data can cause aircraft crashes Especially in case of probe icing.

There is a key difference in the statements: "temporary loss" and "loss" (not temporary).

Taped-over static ports, wasp nests in pitot tubes, and in fact probe icing due to inadequate or failed heating (for example) are not temporary - and had caused crashes prior to AF447.

Incidents where working pitot heaters were overwhelmed for a few seconds, 447 and similar previous, were clearly temporary and could legitimately have been regarded very differently in terms of risk/threat.



And

So in fact the aviation industry (and regulators .. part of it) considered the temporary loss of airspeed like a threat IMHO

Except in 2008/2009 EASA responded to DGAC that there was not an unsafe condition that warranted mandatory probe replacement. See the slides linked to further up the thread, Présentation "Accident AF 447 228 victimes Comment fut traité le. RETOUR DEXPERIENCE. par : 1AF447-REX." (http://slideplayer.fr/slide/1165935/) - slide 42, for one reference. Note: strictly, they did not say there was not an unsafe condition, only that there was not one that was significant enough to warrant mandatory action.

Since EASA is part of the industry, clearly the industry was at least not-unanimous on whether or not temporary loss of airspeed was a threat.

[Turbine D]

Dozy,
Regarding the FAA's point on replacing the Rosemount units, I'd like to see the original document if anyone has a link handy.
Here is a link:

AIRBUS INDUSTRIE Model A300 Series Airplanes (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAD.nsf/0/A19C98E36091A2998625695A00433D6B?OpenDocument)

The AD didn't mandate replacement of the Rosemount pitot tubes, just modification of the pitot probe heater within 1800 flight hours. This applied to the A-300 aircraft.

[DozyWannabe]

Thanks TD, but this seems to be a different case - jcj was taking about A330/340 aircraft in 2002 rather than A300s in 1983.

Cheers for looking that up though - it's interesting nonetheless!

[Turbine D]

Dozy,
I went through all 2002 FAA Airworthiness Directives (AD's) on the FAA site and there were none regarding Rosemount pitot tubes and/or replacements on A-330s, A-340s or any other Airbus aircraft.

Sorry about the first search, I did it by appliance, not year, and that was the only one that came up…

[DozyWannabe]

Right - I think there are definitely some crossed wires going on somewhere...

Cheers again for having a look!

[roulishollandais]

This left the plane in the hands of the two co-pilots, David Robert, 37 and Pierre-Cédric Bonin, 32. Bonin, the least experienced of the three, took Dubois’ seat, which put him in control of the flight.Misunderstanding of the report, of PF vs PM, of position of pilots vs seats, of Crew hierarchy vs seats, of seats pictures in the report. Perhaps Hospital has more to learn from normal aviation uses than from controversary crash CVR.
But exchanging and taking time for reflexion is always difficult but positive.

[DozyWannabe]

Yeah, that write-up gets quite a few things wrong - and says other things which are at best debatable. Safety processes used in aviation making their way into healthcare is nothing new, mind.

[PerAsperaAdAstra]

This may be a dumb query, I fly small stuff for my daily crust, but, 447 and I think it was Condor Air accident Blocked (static ports) interest me. I can understand at alt airspeed in terms of Mach No is important, due to overspeed with Mach crit causing buffet etc. However why does the computer air data program attach quite so much importance to pitot static airspeed? If you have an AOA reading, it just seems to me if the system was programmed to follow the age old Golden Rule of Power+ Attitude=Performance, surely both of those accidents may not have occurred? Again power setting coupled to an AOA readout, would that not be a pretty reliable system as a backup?

I know in 447's case it was complicated by the flight mode it defaulted to, trimming the stab fully nose up, best chance for recovery was at incipient stage, just release back pressure, if only they had known, once in a fully developed deep stall, it would have taken some radical pitch attitudes to recover, at night IMC, not understanding what was happening, that would be a big ask of any crew.

[DozyWannabe]

I know in 447's case it was complicated by the flight mode it defaulted to, trimming the stab fully nose up...

Well, to be fair the trim was only increased to full nose-up because that's what the pilot was demanding of it through the sidestick.

I was wondering if you could clarify a bit what you meant by "...why does the computer air data program attach quite so much importance to pitot static airspeed?".

If you're talking about in terms of the autopilot, it makes sense to automatically disengage it in the event of UAS condition because bad data can cause the AP to pitch the aircraft inappropriately (as in the case of Birgenair 301).

If you're talking about the FBW systems, the only thing they really lose in terms of protection is the hard protections - this is because the pilots should have full authority - introducing bad data to the systems could have unintended negative consequences.

[DozyWannabe]

"Another AF447"? Not even slightly.

In that case the aircraft pitched up as a result of the turbulence itself - the crew correctly tried to counter the pitch with nose down and control the airspeed (the indications remaining OK in this case). The temporary "loss of control" was due to external factors, unlike AF447 where the pilot flying stalled the aircraft and subsequently lost control.

[PerAsperaAdAstra]

I was wondering if you could clarify a bit what you meant by "...why does the computer air data program attach quite so much importance to pitot static airspeed?".

What I meant here was as I recall when the airspeed data corrupted, the aircraft went into alternate law mode, which seems to have added to the crew confusion, yes you are right about the stab trimming nose up due to the sidestick input, but I understood this trimming happened automatically under the "alternate law", recovering from a stall with full up stab trim would vastly confuse things.

This is what I meant by "so much importance to IAS", to me it seems there should be more parameters measured, before he system reverts to alternate law? For example shock stall and crit alpha stall cause the same symptoms as such (buffet), and with a falty IAS reading in IMC, the only sure way to tell the difference is AoA? If the crew had had this, would they have realised they were at low speed, not overspeed?

This may have been discussed earlier, but this was a very interesting accident (very tragic too), as it touches on the clash between classic stick and rudder skills, and modern aircraft AP systems.

(By the way, how do you do a quote on a forum post? I looked in FAQ but no luck? I am anashamedly a very pre computer ager, when I joined the air force, the most odern piece of kit on the Sqn was a hand cranked copier!)

[DozyWannabe]

This has all been covered in the mega-threads, so I'll go over this once only for the sake of my sanity... :ok:

What I meant here was as I recall when the airspeed data corrupted, the aircraft went into alternate law mode, which seems to have added to the crew confusion...

Going by the report, the only reference made on the flight deck was the PNF making the callout from the ECAM. The PF never acknowledged the callout.

Alternate Law should be neither confusing nor a big deal - in a pinch all you need to remember is that the "hard" protections are no longer there - i.e. it's possible to stall or spiral dive the aircraft if you overcontrol (just like a conventional aircraft), and that depending on the mode you're in, the aircraft will be slightly more sensitive in roll. In short, all it means is fly normally but be careful with the controls.

you are right about the stab trimming nose up due to the sidestick input, but I understood this trimming happened automatically under the "alternate law", recovering from a stall with full up stab trim would vastly confuse things.

Autotrim is active in Normal Law as well. I was lucky enough to be able to perform some experiments with a friend in an A320 sim, and what we discovered was that it was possible to roll the trim forward again with sidestick on its own as long as it was caught early enough (link to summary below).

http://www.pprune.org/tech-log/460625-af-447-thread-no-6-a-85.html#post6793521

This is what I meant by "so much importance to IAS", to me it seems there should be more parameters measured, before he system reverts to alternate law?

The drop to Alternate Law had nothing to do with the buffet or any other stall-related phenomena. As I said above, Alternate Law takes away the hard protections (i.e. limits) because the design rightly assumes that the pilots should have the final say if the data being fed to the computers stops the system from working effectively. The control laws are really just the equivalent of what the Flight Engineer used to do in the event of a technical problem - i.e. reconfigure the aircraft's systems in a way that provides the greatest degree of controllability and safety.

it touches on the clash between classic stick and rudder skills, and modern aircraft AP systems.

AP wasn't really involved here, as it disconnected right at the start of the sequence. FBW is *not* automation in that sense.

(By the way, how do you do a quote on a forum post?)

Check your PMs.

[PerAsperaAdAstra]

Thanks Dozy, you seem anything but! Interesting stuff the 447 case. One last question, the sidestick, is it programmed to give a stick force feel, (I think it is?), and will it show sloppiness at low speed, tightening up at high speed as such? Why the need to autotrim the stab with sidestick input? It seems to me a better option to let the FP choose the option surely?

[DozyWannabe]

Thanks Dozy, you seem anything but!

Hahahaha - quite a few folks on here would say otherwise!

One last question, the sidestick, is it programmed to give a stick force feel, (I think it is?), and will it show sloppiness at low speed, tightening up at high speed as such?

No - it's passive spring feel. Breakout from centre position and you know you're doing it, it's a chunky piece of kit! Very well balanced though - check out the summary

Why the need to autotrim the stab with sidestick input?

Easier for the PF, bearing in mind there's no force-feedback. The autotrim system works just fine, though it means that the Airbus FBW series is a little different from a conventional setup there. Interestingly in the A320 sim we found that the trim would stop at a certain point, and had to wind it back manually to simulate AF447's condition - this is apparently different from the A330 which will autotrim all the way if the pilot appears to be demanding it.

[Oakape]

"Another AF447"? Not even slightly

This one was similar -

West Caribbean Airways Flight 708 - Wikipedia, the free encyclopedia (http://en.wikipedia.org/wiki/West_Caribbean_Airways_Flight_708)

Captain flying this time.

[DozyWannabe]

@Oakape: Yup - we covered that on the megathread. What's interesting there is that WCA708 provides an instance of rebuttal to the "connected controls" argument, as that aircraft (an MD-80) had connected yokes, and the PNF still didn't see (or respond to the evidence) that his Captain was in fact pulling harder into the stall. Also that the MD-80's automation was not sophisticated enough to detect that it could not maintain the requested altitude with the engine thrust reduced by the anti-ice system.

[DozyWannabe]

The issue is that we're not given any context as to what that sim session was about. That series was broadcast in 1996.

In general, Black Box was an excellent series, and I still have it kicking around on VHS somewhere - however in this episode it does make the mistake of assuming the technology of the time was a first step in removing the pilot, which was never true.

[Lonewolf_50]

@Oakape: Yup - we covered that on the megathread. What's interesting there is that WCA708 provides an instance of rebuttal to the "connected controls" argument, as that aircraft (an MD-80) had connected yokes, and the PNF still didn't see (or respond to the evidence) that his Captain was in fact pulling harder into the stall. Also that the MD-80's automation was not sophisticated enough to detect that it could not maintain the requested altitude with the engine thrust reduced by the anti-ice system. Incidents like the one cited argue for better training on stall, incipient stall, stall recognition, and recovery regardless of make and model.

Not a technical point, this being Tech Log, other than the matter of technical training associated with operating complex machines.

[Gysbreght]

Winnerhofer:

Stall warning is set to occur before natural (aerodynamic) buffet starts. The stall warning threshold is approximately 1 deg less than the buffet onset AoA. At 7 - 8 degrees the airplane would be well into buffet:


http://i.imgur.com/Qe96igD.jpg?1
P.S.
Although the EICAS is for system failures rather than pilot errors, perhaps a message like: "STALL: RELEASE STICK OR PUSH" would help a disoriented pilot?

[DozyWannabe]

Is the SW programmed to kick in @ 5.8° AOA too early?

Where are you getting this info from? Unless you have a triple ADR failure, Stall Warning is calculated differently depending on the current Mach value. Are you thinking of the FL250 limit with the BUSS due to fixed SW value (not relevant to AF447)?

Incidents like the one cited argue for better training on stall, incipient stall, stall recognition, and recovery regardless of make and model.

Not a technical point, this being Tech Log, other than the matter of technical training associated with operating complex machines.

Hullo sir - as far as the latter point goes, I think it's fairly wide-ranging. I agree totally with your first point, however I also find that incidents like WCA708 and Birgen301 provide a useful counterpoint to those who reflexively claimed that AF447 would not have happened on a Boeing/MD with linked yokes. To be frank, I'd rather such commentary didn't come up - as it is a distraction from the matter at hand - but alas it has done fairly frequently.

[Cool Guys]

incidents like WCA708 and Birgen301 provide a useful counterpoint to those who reflexively claimed that AF447 would not have happened on a Boeing/MD with linked yokes

3 accidents with many other contributory factors is too smaller sample base to draw any definate conclusions

No one is seriously saying AF447 would not have happened in a Boeing. However, many experienced pilots here have explained how a yoke may have helped the pilots achieve a better outcome. Let them have their opinion – jeez

[Pali]

Sorry for a non-pilot making a statement here. The father in law of a good friend of mine was an airline pilot with 25+ years of experience. He started originally on Tu-154 then transferred to B-737 for many years. Then he was supposed to be retrained to Airbus due to changes in the fleet of the carrier he worked for.

He expressed many times his disappointment with FBW environment with sidestick without feedback from control surfaces and said that this is not old school flying anymore and the joy of flying is gone.

Making the long story short the pilot ended his life by suicide. It would be very inappropriate to claim that the old guy decided to leave the world just because of necessity to change to new type of a/c with SS but as the family says he was very bitter with the fact. It is known that suicide cases have (like accidents) more contributing factors. Also this is not an attempt to make a flame war regarding Boeing and Airbus proponents.

What I can say as a consultant which is partly involved with safety in various industries - if the operator on any machine or vehicle doesn't like the controls of it then he is more prone to accidents.

Now back to pro pilots :O

[DozyWannabe]

No one is seriously saying AF447 would not have happened in a Boeing.

You say that, but in the "dark" days of the old AF447 mega-thread, I remember seeing that opinion advanced - usually in complete seriousness - at least once every two or three pages.

However, many experienced pilots here have explained how a yoke may have helped the pilots achieve a better outcome. Let them have their opinion – jeez

I'm not stopping anyone from having an opinion! Though I would question how many of the experienced pilots advancing that opinion have actually flown a FBW Airbus. As you state, three or four incidents aren't really enough to draw a scientifically significant conclusion from. What is noteworthy in an anecdotal sense is that in the time since the Airbus FBW types were introduced and became widespread, there have been more LOC accidents of this type on airliners with yokes than those with sidesticks.

In theory, the connected yokes should provide an extra cue in the visual and tactile channels, but in practice it doesn't seem to make a great deal of difference.

What this means is that no matter what anyone's personal feelings are on the matter, both designs are - as near as we can tell - pretty damned safe, and that the various pros and cons of each are immaterial in real terms.

[Cool Guys]

yeah, Ive read the "mega" thread. There are many interesting and valid opinions from some smart and experienced people.

Because the sample base is very small, a comparison based on statistical evidence has minimal value.

[DozyWannabe]

@Cool Guys - Right - and I remember your posts on the subject and others. If I recall correctly, you're an engineer with an interest, like me.

Experience and intelligence are definitely good things - however the best kind of experience also comes with a continued desire to learn and evaluate changing circumstances. An experienced person who reflexively dismisses a different paradigm as inferior without properly evaluating it is as potentially dangerous as a less experienced person who blindly accepts each change as inherently better.

@Winnerhofer - The MD-80's pitot-static system does not automatically cross-check for data validity in the same way as the FBW Airbus system does. I don't think the author of your linked article is aware of that fact.

[PerAsperaAdAstra]

I haven't got all the facts at my fingertips as I sit here now, will go over the info I have when I get the chance but 447 seems to tie in with the A320 LOC when carrying out an acceptance test flight for the return of the aircraft to service with Air to New Zealand. As I recall, an unplanned approach to the stall was carried out, as IAS was reduced, the aircaft systems trimmed the tailplane full nose up, just before the stall, the engines were powered up, but due to the up trim and the nose up pitch caused by the engine thrust lines on pod engines, the aircraft did not respond to recovery nose down side stick input as was expected. This caused confusion resulting in a relaxing of the nose down input. The aircraft subsequenty stalled and crashed into the ocean.

It seems to me the synthetic feel of the sidestick was an issue, can't help but feel a good old Boeing style yolk would have removed all doubt of what control input and to what extent, was being made? Would like to have a go at a sidestick if I got the chance, as I do regard them with some suspicion...along the lines of, it's all good as long as things are ops normal :hmm:...but when things are going wrong...:uhoh:

[Cool Guys]

Hi Dozy,
In industries that produce equipment that can kill people if it goes wrong, those who are careful about adopting new non validated technologies pose far fewer risks than those who accept new technologies without proper evaluation.

[DozyWannabe]

@Cool Guys - Correct, but I'd say a decade of development and testing (from the Concorde "minimanche" experiments in the mid-'70s onwards) constitutes a very rigorous evaluation process, even by aviation standards.

26 years since the A320 went into service and the number of hull-losses attributable to the FBW system and the flight deck design on all Airbus FBW types remains at zero. The Airbus FBW types have a safety record that compares very respectably with other types and thousands of the things fly daily.

So I'd say that the worst fears of the more reactionary "experienced" pilots back when the A320 was launched haven't come to pass, and on this occasion they were wrong about a lot of things.

[Linktrained]

PerAAA #275


" aircraft trimmed nose up..."
" thrust lines on pod engines..."


How often does one include a visual check of the current state of the trim whilst in normal flight, when it is all done automatically for you ?


How often do you have the opportunity to alter the power from cruising power to flight idle and then back to climb power - whilst in level flight, to see what happens ?


One of the many performance graphs for AF447 appeared to show that power was reduced to Flight Idle - and the nose dropped for a few seconds (as it must). Then TOGA was restored. IIRC this was a few second prior to the final stall. ( I think that nothing was said at the time on the CVR by PF or PNF. The Captain was called at about this time.)

[roulishollandais]

safety recordWe could hope much better records than AF447 and such wonderful flights.

[DozyWannabe]

How often does one include a visual check of the current state of the trim whilst in normal flight, when it is all done automatically for you ?

Sure, but the trim will roll forwards again with sufficient and sustained application of nose-down sidestick (as one would do with a stall recovery).

One of the many performance graphs for AF447 appeared to show that power was reduced to Flight Idle - and the nose dropped for a few seconds (as it must). Then TOGA was restored. IIRC this was a few second prior to the final stall. ( I think that nothing was said at the time on the CVR by PF or PNF. The Captain was called at about this time.)

Power setting was reduced to MCT at 02:11:43 at the point the Captain entered the flight deck. It was then reduced further to IDLE at 02:11:47 and increased to CLB at 02:12:10.

The stall was well established before any of this, and the Captain was present throughout. The CVR transcript shows the crew in a confused state between the reduction to IDLE and return to CLB - in particular the PF's (incorrect, as it turned out) assertion of "crazy" (over) speed and his attempt to deploy the speedbrakes, which was emphatically opposed by the PNF.

@roulis - I was talking only about statistics, meaning that the Airbus FBW types have a record about as good as other types (Boeing/MD etc.) of the same age.

[A33Zab]

A Statistical Analysis (http://www.airbus.com/company/aircraft-manufacture/quality-and-safety-first/?eID=dam_frontend_push&docID=39258)

[DozyWannabe]

A33Zab - Nice summary. Thanks! :ok:

[roulishollandais]

@roulis - I was talking only about statistics, meaning that the Airbus FBW types have a record about as good as other types (Boeing/MD etc.) of the same age...and I was talking about performance of compared statistics as the first tool to accept or not accept the state of design of systems where life is concerned.
"Peut mieux faire" has always been a mean level synonym of mediocrity. "Excellence" must be the aim.:)

[roulishollandais]

Thank you A33Zab.
What I'm seeing at first glance in these statistics :
P.9/20 shows that flight law limited aircrafts needed one decade 1988-1998 to get their stable level : enough testing was missing
P10/20 shows that progressively, regularly, the safety level of pilots not helped by systems was dramatically decreasing threw the whole period 1958-2013 (x3! ). That fact applies to the last generation too despite it is not directly measured in these stats.

Pure curiosity : which are the numbers of fatal events of the DC3 ?
Edit : see my post #285 same page

[DozyWannabe]

P.9/20 shows that flight law limited aircrafts needed one decade 1988-1998 to get their stable level : enough testing was missing

No, read the article. The dotted line indicates that a million flights per year have yet to be reached and that therefore the baseline for statistical significance has not yet been met (hence the dotted line).

P10/20 shows that progressively, regularly, the safety level of pilots not helped by systems was dramatically decreasing threw the whole period 1958-2013 (x3! ).

The graphs on P.10 only begin at the year 1994.

Pure curiosity : which are the numbers of fatal events of the DC3 ?

Difficult to say given the reliability of stats from that period, but if you read "Fate Is The Hunter", it becomes apparent by the end of the book that around half the pilots he trained with in the first chapter are dead.

[A33Zab]

which are the numbers of fatal events of the DC3


source: Aviation Safety Network (http://aviation-safety.net/database/types/Douglas-DC-3/statistics)

Hull loss accidents 2767 with a total of 11744 fatalities.

[roulishollandais]

@A33Zab
Wonderful documentation :ok:
Many of these DC-3 events seem to be military flights or in war zone?
@DozyWanabee
I do agree that starting with Habsheim fatal accident needed many hours of flight to let appear the statistic great number law :}

[DozyWannabe]

Right, but ASN includes former C-47s in their stats, which makes the ratio of hull losses versus number built difficult to determine.

I do agree that starting with Habsheim fatal accident needed many hours of flight to let appear the statistic great number law :}
That accident was caused by poor preparation by the airline and very poor decision making by the Captain, not a technological fault. Don't forget Boeing lost a B707 within a year of its entry into service because the acceptance flight crew exceeded the limits of what they were supposed to be doing : http://aviation-safety.net/database/record.php?id=19591019-0 .

[roulishollandais]

@DozyWanabee
Point for you, I missed the 1994 page 10/20!
It is still worse if the factor 3 of hull losses applies from 1994 to 2013 (20 years) with the new generation of pilots!