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AF 447 Thread No. 6

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AF 447 Thread No. 6

Old 12th Oct 2011, 18:15
  #1221 (permalink)  
 
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HN39. "It would be interesting to imagine....." 200 knots? At 15,000fpm down, and 60 knots forward....... I am interested in what might be considered the type and level of the acoustic environment in the cockpit.

Chris:

I am less embarrassed by my apparent lack of Ae, than I would be to own your lack of imagination.
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Old 12th Oct 2011, 18:27
  #1222 (permalink)  
 
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Let's go for another round, shall we?

Originally Posted by Turbine D View Post
WRONG - Not my quote, you got your "hamsters" mixed up.
My apologies, sir, I indeed wrongly attributed the quote to you. Sorry. I'll do my best not to let it happen again.

Originally Posted by Turbine D View Post
I'll stand to be corrected when you show me evidence of AB's high altitude, high Mach cruise situations, such as UAS events, which are clear and simple.
Interim 3, page 59. Oh, wait a minute...

Originally Posted by Turbine D View Post
Not only does AF's procedures seem confusing, AB's procedures don't seem to me to be much clearer.
So you know about them!

I have some bad news for you, sir. If you think procedures are confusing as you sit comfortably in front of your computer screen, there is no chance in Detroit you'll be able to recognize the one to be applied at 0400 AM at FL 330 when hell breaks loose. You can't be an Airbus pilot unless you radically improve your airmanship. As Boeing procedures, despite indignant and unsubstantiated cries they're otherwise, are not radically different from AB's, you probably won't cut it right now as Boeing pilot either. Or Embraer pilot. Or Tupolev pilot. Or any airliner pilot.

Good news is: given solid & undamaged head mounted computer, clean bill of health, good hand to eye coordination, lots of effort and determination and considerable time, one can become a pilot.

Originally Posted by Infrequentflyer789
AFs procedures at least are clearly confusing since preople here can't agree what they mean even with plenty of time to read them.
Good thing they were designed with pilots in mind, not PPRuNers.

Originally Posted by rudderrudderrat
It seems to me that PF may have simply memorised 3 attitudes and power settings, and forgotten the "Below Thrust Reduction Alt" bit.
Once he had selected TOGA power, then he placed the aircraft at 15 degs pitch and waited.
Flying aeroplanes is tough job! One of the requirements thereof is to promptly tell the difference between "below acceleration altitude (tipically 1500 ft above ground level) and "above FL100". Not for easily confused.


Originally Posted by Gretchenfrage
That there exists a better solution to the problem and that it might just be a better idea to copy that than shout down those who bring up the problem.
Do you have a slightest idea what was the topic you brought on and we were discussing?

It was flight instruments (ATA 31) and autoflight (ATA 22), not FBW (ATA 27)!

Regarding EFIS/AP/FD there is not much difference between Airbus and the rest of the world. Heck, Piper Cheyenne has more FD buttons and not much less FD modes than FBW Airbi. I don't see that allegedly better solution applied anywhere!

Originally Posted by Lyman
Nose down is allowed when the bus is initially dealing with Overspeed
Not applicable as aeroplane was in ALTN law. No overspeed protection there.

Originally Posted by Lyman
I notice your discomfort with a connection twixt UAS and the STALL
There shouldn't be any connection. If it weren't for utterly paradoxical pilots' reaction, that is.

Originally Posted by infrequentflyer789
Does "safe conduct affected" just mean "if no danger of terrain impact" ?
No. It's a tough life in the cockpit, when one has to know all the time what is safe and what unsafe. This game is not for faint hearted. Or feeble minded.


Originally Posted by infrequentflyer789
If most of their crews crashed when faced with the scenario on the sim, then something systematic is wrong at AF and not (only) with the guys on the night. If we knew why they crashed in the tests, then we might be much clearer about why 447 climbed.
You might want to have a look at interim2, pages 100-103. 37 330/340 crews faced with the same problems as AF447's did. In real life, not sim. All survived. Surprise, surprise.

Originally Posted by CONF iture
how do you positively know ALT CRZ mode was engaged when the trace is nowhere to be seen ?
(...)
The FD/AP VERTICAL MODE is a critical parameter for the all event, after, but also before the AP disconnect.
BEA ... where is the trace ?
I have never used anything but ALT CRZ in cruise, never heard of anyone who didn't, interim 3 is pretty clear on it and anyway I don't think that "Superiority of using V/S mode in cruise instead of ALT CRZ on A330 series aroplanes" thesis is going to get anyone that coveted PhD, no matter how original the research will turn out to be.

It's critical... just how? As long as AP is engaged, it's straight and level. When it drops out, aeroplane behaviour is consistent with the sidestick input in ALT law. Do you dispute that?

Last edited by Clandestino; 12th Oct 2011 at 18:48. Reason: cerebral flatulence
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Old 12th Oct 2011, 19:35
  #1223 (permalink)  
 
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Clandestino. Can you school me on Overspeed, and A/P reaction? Also, what of a sudden loss of speed (Indicated) that would require a/p remediation? How does the autopilot control these deviations from "straight and level"?

If the computer senses and controls A/S with Pitch, it obviously stays in NORMAL LAW for the duration. "there is no Overspeed Protection in ALT LAW." If Overspeed prot had latched, and the IAS were lost, what would be the a/c's reaction? What does the a/c do with "Overlap".

IOW, with the a/p's manouvering limits, what occurs to the "gradual" diminution of Control LAW? Say the a/c was in a protection, and the a/p limited out, what then? If in NORMAL LAW in OVERSPEED protection, what does the a/c do with a conflict? How long would NORMAL LAW obtain, after UAS had tripped the a/p?
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Old 12th Oct 2011, 20:27
  #1224 (permalink)  
 
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Lyman,
Except where airspeeds are erroneous due to either blockage of pitots or due to extreme AoA causing large errors in the pitot and static pressures, they correlate closely with groundspeed derived from IRS and GPS. That correlation excludes sudden large loss or increase of airspeed with meteorological origin.

Last edited by HazelNuts39; 12th Oct 2011 at 20:43. Reason: large
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Old 12th Oct 2011, 20:48
  #1225 (permalink)  
 
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@Clandestino:
Originally Posted by Clandestino View Post
You might want to have a look at interim2, pages 100-103. 37 330/340 crews faced with the same problems as AF447's did. In real life, not sim. All survived. Surprise, surprise.
With respect, sir, you (and the BEA) do not know that those "37" other crews faced "the same" problems as AF447 (how many of the multiple elements of each situation are you comparing?). Of course those events listed in interim 2 appendix 7 are believed to be icing events of 2 or more pitot probes, but that is the only similarity which the BEA state. As the BEA explain in interim report 2, there is insufficient data gathered for most of the other events, for detailed examination. Only 13 events had enough information for such examination (see interim report 2, section 1.16.3, PDF page 51 onwards).

As I said to you on 31 Aug the behaviour of some other crews where such detail is known, is not without fault either - so the degree to which AF447 is an exception is far from black & white.

Of course AF447 are the only crew to crash, but that is a very superficial view, IMHO. Look deeper into section 1.16.3 which I mention above, and several similarities with (incorrect) crew behaviour are seen amongst other crews too.
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Old 12th Oct 2011, 21:02
  #1226 (permalink)  
 
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Originally Posted by Lyman View Post
Chris:
I am less embarrassed by my apparent lack of Ae, than I would be to own your lack of imagination.
Let's not get into a reciprocal slanging match (again?) but with more than 30 years in "Ae", I think I know the difference between unfounded imagination and knowledge better than you do, it seems.
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Old 12th Oct 2011, 21:05
  #1227 (permalink)  
 
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Clandestino

I accept your apology regarding the "hamster" mix up.

As to the rest of your remarks directed towards me, well, normally I would ask some questions regarding the small bits of technical input you mentioned. However, I don't think you are the right person to ask anything of, given your mental disposition.

I will say, your apparent suffering from cerebral flatulence that you mentioned, could be a problem, a charm school might help, but you should ask your doctor what's right for you.
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Old 12th Oct 2011, 21:08
  #1228 (permalink)  
 
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Hazelnuts. Hmmm. Groundspeed? GPS? Inertial? I am entertaining transient (brief) discreps. Only as little as 30 knots can cause an ADR problem? Here is what I mean by overlap. Are you saying then that the airspeeds were only erroneous, and can have no basis in reality if their effect was to cause error?

Big airplane, lag to velocity? Besides, if reversing, there is a possibility meteorological challenges can go under the "Radar"? (Discovery).

Chris: I most quickly grant you your observation re: "unfounded" imagination. Imagination, by its nature, is vulnerable to ignorance. If I am ignorant of the platform, I welcome your corrections, no slang intended.

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Old 12th Oct 2011, 23:56
  #1229 (permalink)  
 
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Bloomberg:

Air France Crash Book Shows Pilot Confusion

The first book investigating the Air France 447 crash...
Publishing what he says is the first full transcript of the pilots’ voice recordings, French aviation author Jean-Pierre Otelli describes a scene in the Airbus SAS cockpit that is dominated by confusion, a lack of coordination, and denial among the flight crew as the jet plunged through the night sky toward the ocean surface. Otelli, who specializes in aviation safety, publishes his book “Piloting Error, Volume 5” today.

Air France Crash Book Shows Pilot Confusion - Bloomberg
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Old 13th Oct 2011, 03:20
  #1230 (permalink)  
 
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Documentation

Flight Crew Training Manual Airbus Air France
AFR A330/A340 FLEET PIR-010. P 4/4
FCTM 09 JUL 08
PDF_F_FCTM_AFR_TF_F_EU__20090113_FCTM.pdf
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Old 13th Oct 2011, 10:30
  #1231 (permalink)  
 
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quote Rudderat:
Hi jcjeant,

"99.99% of the PF's manual flying experience will have been in Normal Law, where stick deflection controls a roll rate independent of air speed. When he was faced with ALT Law, he had direct control of the ailerons. You get full deflection of the ailerons with full side stick - independent of the airspeed. The roll rate at high Altitude is very rapid, I've never experienced this this for real - but I am reliably informed that it is "very twitchy".

PF seems to have been struggling to maintain wings level whilst he was over controlling. Whether he was flying fast or slow could not be part of his evaluation - because he probably had no previous experience of ALT Law at high FLs to base his judgement. "

Correct as far as alternate law is in play. In normal law, the roll efficiency starts to decrease above Va (250 knots in the A320 family) to protect the airframe and wing structure. That seems little known to pilots, but when you are under 10000 feet at 250 knots as mandatory, you have the best possible roll efficiency for traffic avoidance (relatively high speed with full aileron deflection).

I learnt recently that the autopilot in cruise "trims" the airplane for 0,9g, but of course maintains 1g through elevator position. When you loose the AP, the plane has a natural desire to climb...Not very useful, but sharing what I learn!
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Old 13th Oct 2011, 11:09
  #1232 (permalink)  
 
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Literal transcription of CVR

Jean-Pierre Otelli's book: "full transcript of the pilots’ voice recordings" acc to the Bloomberg/autor or " a part of a literal transcription of the Cockpit Voice Recorder" acc. to an inflamed BEA ?
http://www.bea.aero/en/enquetes/flig...ctober2011.pdf

Had anyone read it? And found some relevant for accident?
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Old 13th Oct 2011, 11:16
  #1233 (permalink)  
 
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Hi Narval,
When you loose the AP, the plane has a natural desire to climb...
The only aircraft I know which did that was the L1011 during an Auto Land Approach. (AL selected)
Every other aircraft I've flown, when the AP drops out, remains in trim and continues along the same trajectory. I can confidently report that's true for the A320 series in Normal Law. (If it does what it says on the tin - then it should be the same in ALT LAW also)
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Old 13th Oct 2011, 11:58
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Originally Posted by NARVAL View Post
I learnt recently that the autopilot in cruise "trims" the airplane for 0,9g, but of course maintains 1g through elevator position. When you loose the AP, the plane has a natural desire to climb...Not very useful, but sharing what I learn!
Hold up - I remember reading something like that about the A320 (which has a marginal tendency to climb), but also that the same situation is not the case on the A330/340, which hold their trajectory. Is this the same thing we're talking about here?
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Old 13th Oct 2011, 14:16
  #1235 (permalink)  
 
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alexd10, the book doesn't contain a "full" transcription.
=> BEA is right to describe it as "a part of a literal transcription of the Cockpit Voice Recorder".

The book is not a "revolution" in my opinion, but come with some indications. Note that the BEA is right when it wrote:
"This transcription mentions personal conversations between the crew members that have no bearing on the event, which shows a lack of respect for the memory of the late crew members."
Indeed, most of the "new" elements of the transcription in the book are more or less personal and/or not related to the flight.

But, in the same time, the BEA forgot (?) to publish (or delayed it until the final report?) some parts of the CVR which are, from what I understand, relevant to the flight. The most striking example:
02:11:45.5 (PF) On perd le contrôle de l'avion, là
02:11:46.7 (PNF) On a totalement perdu le contrôle de l'avion... On comprend rien... On a tout tenté...
[edit] translation to english, I just tried with google and it's not so good, so here we go for non-french readers:
(PF) We are loosing the control of the aircraft, here
(PNF) We have totally lost the control of the aircraft ... We understand nothing ... We tried everything
[/edit]
=> This is not present in the BEA's report.
=> This is what the two F/O said to their captain when he came back...


On the other hand, nothing appears in the transcription in the book from 02:10:15.9 to 02:10:27.
I.e. it's missing the "Alternalte law Protections (lost?)" from the PNF at 02:10:22, which is present in the report from the BEA.

I think Otelli had access to a different version of the transcription (a previous draft, perhaps?) while the BEA has total access, of course, but choose not to publish it in extenso (for the moment, at last).

Overall, the book shows two things:
- A crew may be more "relaxed" he ought to have been to fly in the ITCZ (prior problems)
- A crew that does "not understand" the situation, and whose actions are beyond logic or procedure ... This is best shown in the book that the report of the BEA.

That's after a quick (and uncomplete) reading.

Last edited by AlphaZuluRomeo; 14th Oct 2011 at 22:03. Reason: adding translation + typo + correcting confusion PF/PNF
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Old 13th Oct 2011, 15:44
  #1236 (permalink)  
 
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NARVAL. If the THS is trimmed to .1 g less than elevators command 1g at cruise in a/p, will it chase .9g if the a/c neglects to cancel that order after the loss of auto pilot? Is that perhaps why it stopped at less than full UP at the STALL? It hadn't zeroed at the start of its uninterrupted migration to 13.9 degrees NU? Without that cue at the start of UP toward the STALL, was it flying anything other than g? Not following the manual input?

AZR. fwiw, "je ne comprends riens..." was part of a leak, early on. It was not claimed by BEA, but BEA did in general rue the release of unapproved data in a memo. No source could be identified for it, but it was discussed here. So technically it is not "new", only re-released, and still not disavowed by BEA......

If it is accurate, it is a bold condemnation of the aircraft and its pilots.

Yes, and the aircraft. For those who disagree, I can only point out the public side of the behaviour and docs exhibited by the BEA. Review them, and take note how the interface among the principals has been a design/build from the outset, and it is yet to reach QA. It is not a report so much as it will be a creation.

One guess as to the goals of the "ARTISTES"

Last edited by Lyman; 13th Oct 2011 at 18:27.
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Old 13th Oct 2011, 17:58
  #1237 (permalink)  
 
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From the appropriate document: (this may have been presented previously)

Max roll rate in Normal Law: 15 degrees/second

Max roll rate in Roll Direct: approximately 20-25 degrees/second (varies with speed and config, but this figure IS MAX)

If you feel this is 'twitchy', be careful (and smooth).

I could get a roll rate of about 60 degrees/second out of a 727 with partial spoiler deployment (increased spoiler roll differential)

That's minimally 'twitchy'.

Max roll rate for a T-38: 720 degrees/second

That's 'TWITCHY'.
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Old 13th Oct 2011, 18:28
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Originally Posted by ChristiaanJ
… but why does it jump to +5000ft/min shortly after the disconnect, and then drop abruptly back to approx. zero?



- The part after the AP disconnect has some logic :
Whenever FD reengage, they do it basic mode, which is HGD – V/S.
The selected V/S commanded by the FD will be the current V/S at the time of the FD reengagement.
There is almost good correlation between both FD and V/S SEL V/S traces, but not entirely.

- The part before the AP disconnect raises questions :
  • Why the SEL V/S is cycling from zero to -5000FT/MIN ? That’s not commanded by the crew.
  • When did start that regular cycling ?
  • The V/S trace in red is partially masked by the green line, but seems to indicate an oscillation getting stronger, up to the AP disconnect.



  • It could indicate that the AP was trying to follow that cycling SEL V/S ?
  • What does indicate the AP/FD VERTICAL MODE trace for that very period ?
  • What does indicate the AP/FD VERTICAL MODE trace for the all event ?
  • Where is the AP/FD VERTICAL MODE trace ?

Last edited by CONF iture; 17th Oct 2011 at 02:13.
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Old 13th Oct 2011, 18:45
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Originally Posted by CONF iture View Post
- The part after the AP disconnect has some logic :
Whenever FD reengage, they do it basic mode, which is HGD – V/S.
If procedures had been followed, the F/Ds should have been switched off until the problem was solved.


- The part before the AP disconnect raises questions :
  • The V/S trace in red is partially masked by the green line, but seems to indicate an oscillation getting stronger, up to the AP disconnect.
  • It could indicate that the AP was trying to follow that cycling SEL V/S ?
Because the red trace is masked it's hard to tell, but it could equally be the lumps and bumps you'd associate with turbulence. Some confirmation that SEL V/S is not used in the mode the aircraft was in would be useful - but there are plenty of explanations, such as the FDR using that channel for something else at that point - I'm almost sure the negative peaks indicate a bad value rather than anything selected though.

Let's reserve judgment until the final report before we get our knickers in a twist though.
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Old 13th Oct 2011, 18:50
  #1240 (permalink)  
 
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CONFiture

Please note in your second graph above, (the truncated version), That the a/c is shown oscillating in vertical speed up 1000fpm, down 1000fpm.
In autoflight. This is actual vertical speed, not selected.

The Selected trace covers it up, but I think it may be important.

edit: Sorry, this is repetitive, and Dozy squeaked my out. I'll leave it, so there is a record of my notation. Not like me to jump the gun before reading your complete post (as if).
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