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AF 447 Thread No. 7

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AF 447 Thread No. 7

Old 18th Mar 2012, 01:34
  #881 (permalink)  
PJ2
 
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Hello Machinbird;

Re your post #869

"Is it proven that the Quick Access Recorder data cannot be resurrected from its time in the depths? I don't remember the answer anymore."

The QAR box etc is located on the main radio rack known as "800VU". It was brought to the surface. There is no information directly stating that the QAR has been found or what condition it may be in. It was stated that the two FMGC memory modules would be examined, (to my recollection the first time that was done was the AA965 at Bogota).

Though not crash-protected, the QAR on this aircraft is almost certainly solid state (vice optical etc) as well and if it survived the initial impact and subsequent water pressure it could be readable.

It's my experience that data frames for QARs is generally far more detailed and sometimes has higher sampling frequencies for some parameters. Let's hope all this comes to pass.

HN39;

Re, " I must admit that my understanding of FD commands is very limited, and I'm just assuming it 'mirrors' the commands that would have been given by an active autopilot."

Yes, that's the way the FDs work - they display the orders that the AFS is issuing, either to the AP or to the pilot flying.
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Old 18th Mar 2012, 01:53
  #882 (permalink)  
 
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Overspeed flying (not recognizing the stall)?

Hi,

mm43,

Is it possible (after stall) their thinking was just of being flying at high speed (and high ROD) just requiring to reduce (the speed) with NU? The inputs they received during the descent could "match" this modeling? Or this is too simple to be considered? (below a K.I.S.S. "safe" threshold). As we understand it seems they never acknowledged a stall. So...

Is it possible?

PS

Like as if the plane "entered" an state they never realized as something plausible. And without enough confidence in the available (considered not reliable, stable and erratic) resources to ascertain "what was happening"

PS2

Again, this is a risky exercise without more factual info. I know.

Last edited by RR_NDB; 18th Mar 2012 at 22:28. Reason: Text impvmt
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Old 18th Mar 2012, 03:44
  #883 (permalink)  
 
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This wreck started with duff speeds, and continued with duff speeds, and duff speeds killed them.

They HAD "crazy speed". The problem is that too much of it was vertical. No STALL recovery was discussed or attempted. It is as you say, and clear as day, they thought they had an overspeed, and whether they sussed their PITCH accurately or NOT, they all signed on to pull, after much apparent confusion.

Too much has been made of how "simple" the soluton was. It was NOT. What does a heavy sound like at 15k fpm descent with an AoA in the roof?

Spinkleman, hear this: I have NOT accused BEA of manipulation of data. What they have done is release too little, and set the stage for a miscarriage of the TRUTH. "OFFENDER"? How so? I counsel doubt, and scepticism, which to me is far short of purposely slandering dead pilots. Make a list of what is MISSING in sounds, conversation,and discussion. Then drive your truck through it.

Assess the state of UAS, STALL training, and high altitude upset recovery. Read Post #66. Ignore what I say, consider only what is missing from a fair stage.

We'll have to see. Patience, there is no other way.
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Old 18th Mar 2012, 12:00
  #884 (permalink)  
 
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Lyman, you were claiming at one point that obviously the VS had fallen off, because Europeans don't understand glue (so far as I understood it).

I understand,and appreciate, your desire to get to the root cause of this crash. It happened in flight school :- when the PF wasn't told to go away.
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Old 18th Mar 2012, 19:06
  #885 (permalink)  
 
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Red face

I don´t know, whether you consider that as an authorative source.

'FAA seeks to raise Airline Pilot Standards'
Hi F4 and JCJeant,
I stand corrected, in French no less. (Wish I could understand WTH they're talking about!) Reading all of the threads, I mistakenly got the impression that most here feel that the stall could have been corrected, mostly from earlier posts. I confused that issue with a separate one: the stall should not have happened in the first place.

I hate to add more useless noise to the discussion by posting this, on the other hand, I feel it is important to acknowledge my mistakes. I only like to appear arrogant if I actually know what I'm talking about! (Happens occasionally.)

Carry on gentlemen.
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Old 18th Mar 2012, 20:09
  #886 (permalink)  
 
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Originally Posted by HN39
Quote:
Originally Posted by Machinbird
FD data became available just in time to be suspect as a cause for the second pull up

What are your reasons for suspecting that the FD causes the second pull up
Just that Airbus/EASA were concerned enough about that configuration to publish an AD about it. AD No.: 2010-0271
http://ad.easa.europa.eu/blob/easa_a...AD_2010-0271_1
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Old 18th Mar 2012, 20:13
  #887 (permalink)  
 
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Originally Posted by RR NDB
Is it possible?
For at least 15th time on AF447 related threads: yes, it is not just possible, it happened before. There was at least one other crew mistaking stall buffet for overmach:

ASN summary of Northwest Orient B727 N274US accident near Stony Point on DEC 01 1974 with link to NTSB report included.

Originally Posted by alanp
It happened in flight school :- when the PF wasn't told to go away.
Could be, but so far I see no proof to it as: a) three preliminary reports are quite elaborate on the technical matters while being pretty thin on HF side b) being competent pilot does not come granted after the training obstacle course has been negotiated. It is matter of keeping oneself fit to fly; there was many a pilot with five-digits total times who perished after making a beginner's mistake c) there's the additional issue of CM1 not recognizing that pulling 15° ANU at typical cruise level is very bad idea or what is the significance of computer shouting "STALL STALL STALL". It's all very well discussing cockpit authority gradient but we are looking at failure of CM1 to realize the gravity of the situation and that CM2 actions will turn out to be lethal pretty soon. Idea of having two pilots is the same one behind having doubled or tripled ADC, IRUs and NAVs - CRM and MCC does not mean we use each other as a crutch but rather that as long as both pilots independently arrive to same conclusion where the aeroplane is, where it is going and where it should be going there's good chance they're correct.

Originally Posted by Organfreak
I mistakenly got the impression that most here feel that the stall could have been corrected, mostly from earlier posts. I confused that issue with a separate one: the stall should not have happened in the first place.
Second notion is totally correct, first notion is correct up to the certain point in time which cannot be precisely determined as no other A330 has ever ventured into AoA achieved by AF447. Given the pitch-down of the A330 when the sticks were released, chances are aeroplane could be recovered successfully until there was no sufficient altitude available to recover from dive. While it is certain that A330 can be recovered from stall if recovery is initiated as soon as practicable after G-break, we don't know what was the latest time/level at which recovery from extreme AoA had to be initiated. It could be FL300 or FL200 or even FL100, perhaps there will be enough data for aerodynamists to say their verdict, perhaps we'll never know.
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Old 18th Mar 2012, 21:00
  #888 (permalink)  
 
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Thiells 727 (misleading) similarities

Hi,

Clandestino:


There was at least one other crew mistaking stall buffet for overmach:

Indeed there are similarities on this ferry flight with AF447 case. I commented this in an earlier post, IIRC on UAS and Pitot generating false (misleading) inputs to the crew.

Their (heater off) Pitot's "failure mechanism" generated false (increasing) speed misleading the crew during the climb.

I will locate my post and will be back with a comment on what i see common between both cases.

Anyway in both cases the stall buffet probably played an important role in their thinking, i agree with you. A dangerous one (the role).

In AF447 what is impressive is how (and why) they failed to even understand (timely) they simply (after stall) were not flying. Just performing a "free fall" trajectory (at near terminal speed).

The role of the man machine interface "performed similarly" to the (much simpler) one of the 727: Not helpful.

Will think and compare HF aspects in both before continuing.

Last edited by RR_NDB; 18th Mar 2012 at 23:21. Reason: Add link, text impvmt
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Old 18th Mar 2012, 22:34
  #889 (permalink)  
 
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Hiya RR NDB

I do not know if this is pertinent, but on 330, Stall buffet is encountered after the STALL WARNING, so buffet should not be confused with high Mach.

(In ALT and DIRECT LAW, obviously).

ciao paisan
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Old 18th Mar 2012, 22:44
  #890 (permalink)  
 
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Originally Posted by Clandestino
It could be FL300 or FL200 or even FL100
Once the airplane was deeply into the stall, I think a distinction has to be be made between whether the airplane was physically able to recover, and what psychologically the pilots could reasonably be expected to accomplish.

As I gather with my scanty understanding of the French language, AB Chief Test Pilot J. Rosay states in the video (post #863) that the airplane's physical capabilities at extreme AoA have not been determined in flight test and thus will remain somewhat speculative.

Apart from the question whether the simulator reflects the real airplane, the psychological aspect is amply illustrated in "post #66" of the other thread:
Originally Posted by NEDude
Recovery at high altitudes require significant nose low pitch, to be held for a very uncomfortably long time, and you have to accept a VERY high rate of descent (15,000fpm or higher).
For example, around 02:13:20 the airplane descended through FL120 with pitch attitude +10° and FPA -40°, i.e. AoA= +50° (assuming still air). To unstall and stop the stall warning, the airplane would need to be pitched down until the AoA was less than approximately 10°. Even if the airplane would respond to forward sidestick by pitching down, the lift and drag forces and hence FPA and airspeed would not change significantly until the airplane was unstalled, i.o.w. the airplane would have to pitch down to an attitude of -40 +10 = -30° to stop the stall warning. That attitude would then have to be maintained for some time until the airspeed had increased enough to permit a pull-up from the dive.

Last edited by HazelNuts39; 21st Mar 2012 at 14:29. Reason: Error in SW AoA corrected
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Old 18th Mar 2012, 23:00
  #891 (permalink)  
 
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Cool

Hi,

Nothing to do with AF447 A330 but this recovery of the Tarom A310 show how the pilot go in a steep dive to recovery ....
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Old 19th Mar 2012, 00:07
  #892 (permalink)  
 
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Phugoid Curves

The diagram is from NASA TM X- 73,229 which is about recovering hang gliders from dives, but has broader implications as well as a fair bit of aviation history behind it.

Do you see a connection with the TAROM Airbus over Paris, the Interflug A310 on approach to Moscow, and for that matter what the AF447 crew would have faced in recovering their aircraft to level flight if the trim did not run down quickly enough?
Just trading potential and kinetic energy.
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Old 19th Mar 2012, 03:03
  #893 (permalink)  
 
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Trading potential and kinetic energy

Hi,

Machinbird:

Tarom Airbus A310-325 24 SEP 1994

Interflug Airbus A310-304 11 FEB 1991

Feedback systems in action. And for Ho you need 3Ho

Question: What about air density change effect during the descent? Seems to me makes easier the recovery. Dampens, provides more lift, ground effect
(it comes to my mind Ekranoplan. You mentioned Interflug
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Old 19th Mar 2012, 13:48
  #894 (permalink)  
 
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Machinbird,

Thanks for an interesting reference.
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Old 19th Mar 2012, 20:22
  #895 (permalink)  
 
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Originally Posted by Machinbird
The man's scan was obviously broken at that point. He was not monitoring pitch! If I may ask as a non-pilot: If you're struggling with roll control and your scan has narrowed to the ADI, is it plausible that you miss pitch altogether?
Most likely not, but you may not focus on it as much, depending on a lot of things. It also depends on what scan you are using. While I cannot fathom a scan that does not depend upon primary reference to the Attitude Indicator (Artificial horizon) that takes a primary reference pitch and roll, and then crosschecks from there), even that scan basis, if rusty from disuse, can break down under stress.
Is it possible that he was aware of increasing pitch attitude, but didn't care because 15° was his target all along?
While I would hope not, it seems that IF he was paying attention to his pitch, THEN he had a target pitch in mind. 12 def? 15 deg? 10 deg? Hard to say. As was discussed some threads ago, an element of the scan breakdown may have been him used to "flying the bird" (FPV). If the bird wasn't behaving as usual, or had dropped out, etc, then getting his scan into operation using the pitch/roll, cross check all else, might have taken him a few cycles to realize needed doing. If he ever did.
Perhaps he only reluctantly and half-heartedly gave in to the PNF's urging "You're climbing, go down" until at 02:10:49 he changed his mind and went for 15° instead. Was there perhaps a similar mental process taking place at 02:11:32 when he admitted "I don't have control of the airplane anymore now (...) at all" and, after the PNF had taken control, abruptly took the controls back?
What he was seeing didn't match what he expected, that much seems to be true.
Nerves of steel? Ice water in the veins. I doubt it. "We are going to crash, this cannot be..." "Four spades? Double". Eh?
Heh, that made me laugh.
Retired F4 Thanks for this:
As for the AF447 accident: I am an instructor on the A320 and we are now doing high altitude stall demonstrations during recurrent training. When given similar circumstances as the AF447 guys, less than half of the pilots can successfully recover even when they know it is coming. It is not because the pilots do not know how to recover from a stall, it is because pilots at all levels have not been trained in the dynamics of high altitude stalls. High altitude stalls are very different animals. Recovery at high altitudes require significant nose low pitch, to be held for a very uncomfortably long time, and you have to accept a VERY high rate of descent (15,000fpm or higher).
AFTER that you have to have a very slow pitch up because a secondary is very easy to occur. Historically when training stalls pilots are taught to lower the nose to the horizon and add full power and to minimize altitude loss. You cannot recover from a high altitude stall using that procedure. If you read what happened, and know how to correctly recover from a high altitude stall, it becomes clear that the AF447 guys were caught off guard because the aircraft did not recover in a way they were accustomed to when training lower altitude stalls. I have a lot more sympathy for the actions of the AF447 guys having trained and demonstrated high altitude stalls in Airbus FBW aircraft.
Flying in a flight regime they weren't trained for. That has killed more than a few ...
alanp: I understand,and appreciate, your desire to get to the root cause of this crash. It happened in flight school :- when the PF wasn't told to go away.
Maybe, but I think it's fair to say that the training and qualification system at AF seems to have some play in this accident.

1. How well equipped was this crew for the UAS drill? CVR seems to show that the response didn't quite fit what was in the book at the time. Training issue?

2. How well grooved was the instrument scan of either pilot?

3. CRM question: how does the LH seat pilot's scan, or lack thereof, and his attempts to get RH seat pilot back into the game reflect on the currency and training at AF?

4. As asked with some frequency before, how much time hand flying at 37K did any of the AF pilots have?
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Old 19th Mar 2012, 22:07
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Cool

Hi,

4. As asked with some frequency before, how much time hand flying at 37K did any of the AF pilots have?
I think we could very quickly have a simple answer to this question if some Air France pilots (who certainly read this forum) would dare answer ...
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Old 19th Mar 2012, 23:36
  #897 (permalink)  
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All,

I have read all and I mean all the pages and grow dizzy with the content but, with no great confidence, do I recall correctly reference at some point by someone no doubt better informed than me, to AF SOPs (et al) specifically forbidding hand flying up there without a d*** good reason?
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Old 20th Mar 2012, 01:20
  #898 (permalink)  
 
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Cool

Hi,

specifically forbidding hand flying up there without a d*** good reason?
Why this interdiction ?? .. it's so dangerous .. ? .. so .. this can explain why AF447 had some ... troubles .....
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Old 20th Mar 2012, 02:07
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Why this interdiction ?? .. it's so dangerous .. ? .. so .. this can explain why AF447 had some ... troubles .....
You just have to be smooooooth to fly in cruise at altitude. Actually no big deal once you relax. Unfortunately, AF447's PF was anything but relaxed or smooth. The unexpected cavalry charge set his heart racing and it appears he never did begin to fly cooly and deliberately. He continued to beat snakes with the stick all the way down.

Unless you are in RVSM airspace, pilots should be grabbing a few minutes of stick time just to keep the feel of the aircraft. What kind of back up system can you be if you don't actually fly?

Sim time twice a year? Give me a break. Flying is one of those skills that needs more frequent refreshing. Sims are close, but not quite the real deal. On an 8 hour+ cruise, the extra fuel used because you are hand flying for 5 minutes can probably be measured easily with a cup, that is, if you are smooth.
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Old 20th Mar 2012, 02:22
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Machinbird

Yes, and no. My neighbor flew the baby bus for ---Lines for many years. He was out of NORMAL LAW, exactly: not once. I am not sure what manual stick (NORMAL) accomplishes up high. The sim cannot duplicate what these three inherited. I could argue that it is a negative, perhaps imparting a false security when LAW degrades for real (which is hardly ever).

BEA say the a/c rolled right to 8 degrees, they do not mention trend, and therefore people assume it stopped at 8 degrees, right? The a/c started a rapid and cyclic ROLL that you have eloquently described, and hand flying in NORMAL LAW is nothing like it. It is NORMAL Law itself that wants mayonnaise, and AL that wants smoothe; so practicing mayo up high is exactly wrong, and could be the source of the entire problem? DIRECT ROLL with mayonnaise is poison.

There is one salient point that is my take away, that BEA mentions very directly.

Pilots of this aircraft MUST have an AoA reference, PERIOD.

cheers sailor.

Last edited by Lyman; 20th Mar 2012 at 02:59.
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