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AF447 Thread No. 3

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AF447 Thread No. 3

Old 1st Jun 2011, 15:00
  #1001 (permalink)  
 
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@sensor validation
No, I was only challenging takata.
I am definitely with PJ2 and Lemurian. Only at one point

Lemurian wrote
"That means that the captain must be at his LHS for T/O and LDG. Which makes him take in 99% of the flights the middle slot."
he was mistaking, but this was corrected by PJ2 already.

We dont know for sure yet whether the captain took his seat again, but also for reasons explained earlier, I very much doubt.
This leaves me with:
LHS relief FO 4400 hrs on type
RHS FO 800hrs on type
3d occupant captain 1700hrs on type
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Old 1st Jun 2011, 15:02
  #1002 (permalink)  
 
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If it's too late to get out then you better assume you are not in!

Originally Posted by BOAC
Purely a ball park guess - if a correct attitude change had not been made by 20,000 ft it would be a done deal.
So , anyone else care to suggest a number, because it has a bearing on crew actions. Some people are saying "how come they did not catch on in over 3 mins", well perhaps they did, lets just say you are descending through 20'000 at 10'000fpm and have two options;
A- stall, pretty sure it is, but (according to BOAC's SWAG) it is too late.
B- A dive, pretty sure (now) that it isn't but it is NOW the only recoverable option so I better go with it.

Persisting with a bad choice is sometimes the only option you have no matter how slim. It may well be guys that you only get one shot at this. I think they were dealt a real bad hand.

Last edited by paull; 1st Jun 2011 at 15:20. Reason: Noted EDLB's 15,000 ft estimate.
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Old 1st Jun 2011, 15:02
  #1003 (permalink)  
 
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Cool

Hi,

Business Week : (another "official leak")

Air France Crew May Have Faced Baffling Data in 2009 Crash - Businessweek

"The data and cockpit voice recording suggest the pilots never realized that the plane had stalled, BEA Chief Investigator Alain Bouillard said in an interview.

“They hear the stall alarm but show no signs of having recognized it,” he said. “At no point is the word ‘stall’ ever mentioned.”
"
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Old 1st Jun 2011, 15:24
  #1004 (permalink)  
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Originally Posted by JD-EE #928
...is there a distinct display for the pilots when the plane is actually stalled rather than facing an imminent stall? If not, wouldn't that be a worthwhile addition to the software?
JD-EE;

Couple of points for discussion:

The "stall" isn't as demarcated a break-point as it may seem. A wing, especially complex designs such as the A330 (and most other transports) does not stall "all at once", (this is by design), nor does it necessarily stay in a stall. In fact I don't think this stall could be defined as a "deep" stall in the way that Davies meant it in his book, but that's another rabbit trail.

The PFD [Primary Flight Display...horizon, speeds, altitudes, heading, vertical speeds, autopilot modes, etc] speed scale provides very clear information on those speed regimes approaching the stall, (photo of a PFD "at alpha-max", not yet in the stall, below) and, if the speed is available, provides sufficient information for crews to keep themselves out of that regime.





Many here have advocated an AoA indication be provided among the standard displays, probably on the PFD. I have flown aircraft with AoA (B727) and like the idea and believe a sufficiently detailed discussion about the desirability, technical viability, reliability and certification of such indications is needed. The problem is made quite complex by broader factors and priorities such as the industry's approach to training and standards in re the use-and-abuse of automation, flying and problem-solving skills, etc. The broader question always is, Do we design more fences and interventions? Just because we can, should we?

Some very respectable observers have said in response to the question, "yes, we design more automation". I am not in disagreement with that view.

But it is not easily, nor simply discussed and settled. What is meant by "more"; how is it to be designed, certified, implemented, trained?

Already, the industry is discussing automated responses to TCAS and EGPWS events and tail-strike automation is already a reality on long-body aircraft. Clearly, those two interventions alone are extremely complex but not at all impossible to do.

An automated response to the stall? Again, not impossible - the question absolutely requires much discussion between many interested parties. I'm sure that discussion has been underway in some venues already. For basic starters, one has to define "stall", and when the intervention takes over and when it hands control back to the pilot.

The interesting comment has been made about resisting automation may actually "cause" more automation. I think that's okay. There is no resistance to automation in any of the comments that I've made. I've always advocated training (and getting into the books) to achieve a solid comprehension of one's airplane. (The balance between adhering to SOPs, and diverting from SOPs through one's 'understanding' of the airplane is a perrennial problem...not easily solved...how much "initiative" does the industry give pilots, how much do they stay away from trying things?...big questions, very relevant today).

My strong and consistent resistance is to the idea that we, (and our managements, the regulator, the safety people), can relax because of automation. THAT, to me is the problem.

The problem is driven by money, politics, convenience (of hiring/training) and the industry's spectacularly high level of safety, (which I believe is being taken for granted by newbie managers who have no idea of history and how the industry's safety record was achieved).

To your question, I'm not an aeronautical engineer so cannot explain the two questions you're asking: 1) What are the actual dynamics of the stall in a large transport aircraft?, and 2) How, in practical terms, might "the stall" be displayed to the pilots in such a way as to provide unequivocal guidance, in very bad circumstances, (weather, system failures, etc) for manual pilot recovery.

Perhaps HN39, or gums, Graybeard, Machinbird, Chris Scott and others can discuss the questions - HN39 and I had a great discussion about AoA on the second thread and I learned a LOT about the A330 and high-altitude stalls. Presenting the information swiftly, accurately and in a way that clearly shows trends either way, are fundamental requirements.

It has to be understood and accepted that the design and certification of such a system are monumental tasks, and that the questions are being asked within the context of other possible solutions to the problems outlined and discussed on this thread. Choices would need to be made as to which solution is best. Such decisions are by no means solely informed by the "flight safety" discourse and the moral question.
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Old 1st Jun 2011, 15:49
  #1005 (permalink)  
 
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Originally Posted by jcjeant
...BEA Chief Investigator Alain Bouillard said in an interview...
Where/when? We'd all like to read about everything he said!
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Old 1st Jun 2011, 15:55
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Cool

Hi,

Where/when? We'd all like to read about everything he said!
Those people have the answer to your question:
Mary Schlangenstein and Mary Jane Credeur

An automated response to the stall?
More simple a automated system for avoid stall condition ?
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Old 1st Jun 2011, 16:00
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EDLB

How much G would be available for the dive recovery, if they had broken th stall in ALTN LAW?
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Old 1st Jun 2011, 16:06
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PJ2

Interesting post.

An automated response to the stall? Again, not impossible - the question absolutely requires much discussion between many interested parties. I'm sure that discussion has been underway in some venues already. For basic starters, one has to define "stall", and when the intervention takes over and when it hands control back to the pilot.
Indeed...I wonder how any such proposed automated solution, if it is being postulated, would handle something like a stick shake at rotation due to LE's retracting (e.g. BA 747 at JNB not that long ago) ........
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Old 1st Jun 2011, 16:13
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Originally Posted by jcjeant
...BEA Chief Investigator Alain Bouillard said in an interview...
Where/when? We'd all like to read about everything he said!
jcjeant did provide a link, see his post.

This is the second BEA-attributed statement today, after the one in Flight. It seems BEA may have realized that their Friday report may not have had the effect of dampening speculation that they hoped it would.
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Old 1st Jun 2011, 16:19
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If there were a fatal flaw in any component, hdwe, sw, or training, it would not be revealed until the fix was ready. The last thing the world needs is grounding of 1,000 airplanes until a fix for a once-in-ten-year event is found, thoroughly tested and implemented.

Meanwhile, if the above were true, the pilots would have to take the heat.
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Old 1st Jun 2011, 16:33
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Hi Blujet,
Originally Posted by Blujet
This leaves me with:
LHS relief FO 4400 hrs on type
RHS FO 800hrs on type
3d occupant captain 1700hrs on type
As it seems that we are in agreement about where was seated the relief pilot, I would like to understand what makes you to believe that the RP was FO1 (4400 hrs)?

Edit: see PJ2 answer to Lemurian, they both agree to the opposite:
Originally Posted by PJ2
Originally Posted by Lemurian
- In all certainty, the operation of this flight was performed by a senior F/O seating on the RHS with command functions and a junior F/O seating on the LHS with basic radio-com and navigation duties, along with some minor engineering duties.
Agree.

Last edited by takata; 1st Jun 2011 at 16:46.
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Old 1st Jun 2011, 16:38
  #1012 (permalink)  
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Here's another hare to start running. From Der Spiegel, I believe:

"Just over a year ago, Hüttig recreated the Air France crash in a flight simulator. In the course of the exercise, Hüttig noticed a strange anomaly in the plane's reaction once it goes into a stall. The trimmable horizontal stabilizer, a flap instrumental in keeping the plane on an even keel, automatically adjusted to push the nose of the plane skyward. Hüttig, a former Airbus pilot himself, and other pilots present for the test were unable to push the nose of the airplane down and thereby escape the stall.
When the BEA released its preliminary report last Friday, Hüttig immediately zeroed in on data relating to the trimmable horizontal stabilizer. During the final minutes of flight AF 447 as it plunged toward the Atlantic, the flap moved from a 3 degree deflection to a 13 degree deflection, almost the maximum possible. "The phenomenon is startlingly similar," he told SPIEGEL.
A Quiet Reaction
Hüttig passed along his simulator findings to Airbus, the European Aviation Safety Agency (EASA) and to BEA. On Oct. 27, 2010, Hüttig received a response from EASA which said that Hüttig's theory was inconsistent with the "current state of knowledge." "We suspect that the anomaly you found originated with the simulator you used in the study rather than with the airplane model A330," the response read.
Hüttig and Jeinsen told SPIEGEL that the data recovered from the wreck of flight AF 447 would now seem to have corroborated the simulator findings. Furthermore, Airbus has quietly reacted to the safety loophole. In a communiqué to airlines, Airbus provided a new version of pilot instructions for dealing with a stall. Furthermore, in the January issue of its internal safety magazine, there is a mention of manually trimming the horizontal stabilizers.
In response to a SPIEGEL query, Airbus rejected Hüttig's theory."

Hey ho!
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Old 1st Jun 2011, 16:46
  #1013 (permalink)  
 
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Greybeard

If there were a fatal flaw in any component, hdwe, sw, or training, it would not be revealed until the fix was ready. The last thing the world needs is grounding of 1,000 airplanes until a fix for a once-in-ten-year event is found, thoroughly tested and implemented.

Meanwhile, if the above were true, the pilots would have to take the heat.

Agree ..... mostly

It's too late to make the aircraft fly itself. It can be flown safely if one knows how even with an unexpected disconnected AP. Now how should we address the problem?

me thinks the pilots should not be held responsible to solve this problem
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Old 1st Jun 2011, 16:58
  #1014 (permalink)  
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wiggy;
I wonder how any such proposed automated solution, if it is being postulated, would handle something like a stick shake at rotation due to LE's retracting (e.g. BA 747 at JNB not that long ago)
And all other combinations of such events...it is an exceedingly difficult problem with which to come to terms, and really, when we come to thinking hard about it, the "goal" is informed by "mistakes and avoiding them" in more complex, crowded systems, (transportation), and therefore is to supplant human perception and response under the heading of avoiding "human error" for the purposes of commerce. Training and experience go a long way but so do error-trapping habitual behaviours where it is assumed that at each "fork in the road" so to speak, one "will" make a mistake, and so a form of "recursive" behaviour (constant revisiting of decisions/actions - not "second-guessing" but quietly, constantly confirming/re-affirming "normal"). It works for error trapping but not for system faults and emergencies, where SOPs, training, memorization and simply knowing one's airplane are irreplaceable responses.

The discussion on automation interventions is first, philosophical, and that does not mean merely specifiying and quantifying techniques but examining cognitive processes and the assumptions underlying the philosophy of mind. This won't go over well here I know, because this is a Tech Forum, but all that can and has been done in the name of "technique" and "automation", rests upon such assumptions about perception, response and cognitive processes whether we choose to examine them or not. I think it is better to examine them and know upon which basis our choices are being made in terms of system design, but one person ain't going to change policy.

Graybeard;
...until a fix for a once-in-ten-year event is found, thoroughly tested and implemented.
Absolutely spot on.
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Old 1st Jun 2011, 17:04
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When looking into the aerodynamics corresponding to the 'TE plot' I posted earlier, it became apparent that the tentative trajectory demanded load factors that exceed the maximum lift capability after 2:11:10.

TEplot2 shows the revised trajectory and speeds.

TE_Angles shows the corresponding angles of attack and pitch.

(With all appropriate caveats)
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Old 1st Jun 2011, 17:11
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Originally Posted by Galaxy Flyer
How much G would be available for the dive recovery, if they had broken th stall in ALTN LAW?
Provided everything works as advertized, 2.5 G.
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Old 1st Jun 2011, 17:17
  #1017 (permalink)  
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Here's another hare to start running. From Der Spiegel, I believe:

"Just over a year ago, Hüttig recreated the Air France crash in a flight simulator. In the course of the exercise, Hüttig noticed a strange anomaly in the plane's reaction once it goes into a stall. The trimmable horizontal stabilizer, a flap instrumental in keeping the plane on an even keel, automatically adjusted to push the nose of the plane skyward. Hüttig, a former Airbus pilot himself, and other pilots present for the test were unable to push the nose of the airplane down and thereby escape the stall.
When the BEA released its preliminary report last Friday, Hüttig immediately zeroed in on data relating to the trimmable horizontal stabilizer. During the final minutes of flight AF 447 as it plunged toward the Atlantic, the flap moved from a 3 degree deflection to a 13 degree deflection, almost the maximum possible. "The phenomenon is startlingly similar," he told SPIEGEL.
A Quiet Reaction
Hüttig passed along his simulator findings to Airbus, the European Aviation Safety Agency (EASA) and to BEA. On Oct. 27, 2010, Hüttig received a response from EASA which said that Hüttig's theory was inconsistent with the "current state of knowledge." "We suspect that the anomaly you found originated with the simulator you used in the study rather than with the airplane model A330," the response read.
Hüttig and Jeinsen told SPIEGEL that the data recovered from the wreck of flight AF 447 would now seem to have corroborated the simulator findings. Furthermore, Airbus has quietly reacted to the safety loophole. In a communiqué to airlines, Airbus provided a new version of pilot instructions for dealing with a stall. Furthermore, in the January issue of its internal safety magazine, there is a mention of manually trimming the horizontal stabilizers.
In response to a SPIEGEL query, Airbus rejected Hüttig's theory."

Hey ho!
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Old 1st Jun 2011, 17:25
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HazelNuts39 .... it became apparent that the tentative trajectory demanded load factors that exceed the maximum lift capability after 2:11:10....
thats the pancake at 2:11:30 with 3 deg pitch and vz=-10000fpm
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Old 1st Jun 2011, 17:53
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jcjeant, it may be appropriate to define how you are using fault.

If the PF caused the crash it does not automatically follow that "He is at fault."

Why did he do what he did? If we isolate a training deficiency, a software deficiency, or some other deficiency then while the PF may have caused it he is not at fault for it.

several others, the PF was apparently the 38 year old co-pilot with over 4400 hours on type and a license allowing him to take over from the captain. The 32 year old co-pilot did not have a license to take over from the captain. He did have 807 hours on type. So my reading of this data from the June 2009 Interim Report suggests strongly that PF was the older co-pilot.

Of course, I'm not ready to "blame" either one of them, yet. It appears the cockpit crew may have reacted correctly per training and manuals and had an experience that contradicted that training.

I also note plaintive requests for experience flying ALT2 - I wonder how often A330/A340 aircraft fall into ALT2, how often they train for it, and, in only a semi-serious tone, is ALT2 survivable? It is apparently rare. (And, yes, some people appear to have survived it.)
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Old 1st Jun 2011, 18:11
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Some people here are missing a very fundamental point regarding the BEA release.

Its job was to give up just enough information, about a story of massive interest, to satisfy the general media - who will then go off and write about other stuff.

To suggest the BEA release contained every scrap of new information, and that it couldn't possibly give out any more to specialised aerospace journalists who know what they're talking about, is ludicrous.

And suggestions that professional journalists should shut up and just regurgitate press releases, instead of having the savvy to ask for those additional bit of information - the bits which the daily-rag press isn't interested in - is the sort of nonsense which doesn't belong in a sensible discussion.
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