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AF 447 Thread No. 6

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AF 447 Thread No. 6

Old 24th Sep 2011, 04:50
  #981 (permalink)  
 
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Cool

Hi,

To me, a "large" hole would imply a significant enough size to reduce lift, which never happened due to a tyre burst.
Nothing to do with lift .. but with flow
The Concorde problem was hole (s) in the fuel tank !
And this happened to Concorde (Washington event) long time before the Gonesse accident.

The BEA is a different institution than it was in 1979
The BEA is exactly the same institution today than in 1979
a service of the Directorate General of Civil Aviation (DGAC), which in turn supervised by the Minister of Transport
Same duties .. same hierarchy ...
Or tell me what is changed .... ?
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Old 24th Sep 2011, 15:44
  #982 (permalink)  
 
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"A Big Fat Lie". If anyone has charged BEA with falsification, where is it? To my knowledge they have merely created a climate of doubt, absent the full disclosure of recorded data.

There is no evidence that the autos helped STALL the a/c, neither is there exculpatory evidence. None of either kind have been disclosed.

Since there have been well documented instances of a/c behaviour that did create dangerous flights, it would seem in the best interests of all to see, read, and hear the (complete) CVR/FDR.

Until then, the argument isn't worth the blood flow.

Except to say. Read the BEA report re: THS 'movement' at the start of the climb post handoff. Several times if necessary. Very odd, and very erm, "well-devised".
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Old 24th Sep 2011, 16:09
  #983 (permalink)  
 
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Hi,

May I ask some Airbus- related questions out of general interest?

1. Do Airbus flight controls use artificial feel units?

2. If they do, how would it behave in a scenario with unusual airspeed readings, like AF 447 had? Because an AFU needs airspeed input right?

3. Is this of any significance?

Thanks
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Old 24th Sep 2011, 18:36
  #984 (permalink)  
 
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@DA-20 monkey:

Nope - Airbus sidestick feel is implemented via passive springing. It takes more effort to deflect the further you move it from the centre, but there's no force-feedback as such.
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Old 25th Sep 2011, 14:41
  #985 (permalink)  
 
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Originally Posted by DozyWannabe
A Service Bulletin also says "fix this" - the difference between that and an AD is that the aircraft should not be considered airworthy without the repair being done promptly (and supervised by the regulatory authority) in the case of the latter, which was not the case based on the evidence prior to AF447.
No Dozy.
Service Bulletin = You may fix this
Airworthiness Directive = Fix this (but that does not necessarily require immediate compliance prior next flight - You might as well have a full year compliance time)

No justification to state anything like this :
"An AD would have resulted in the grounding of all A330 and A340s"
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Old 25th Sep 2011, 15:13
  #986 (permalink)  
 
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Airworthiness Directive. The owner is ordered to make the repair, with a schedule supplied by the Regulating Authority. Unlikely that the pitot r/r would have involved a RTB anyway. Clearly, the Regulator was good with the "at your leisure" pace set by Airbus. No one entity can be singled out for this egregious lapse in safety concerns. To me, all three are equally culpable.

After BA038 went in, UAL discovered a non compliance issue with the fire Bottle #5 Inspection Record in their 777 fleet. They recalled all a/c back to station for an inspection, immediately. It was deferrable, but the line chose to exercise caution.

This foot dragging by AF with the pitots is classic backscratching. It is similar to the "negotiated" relaxation of the TRENT inspections on the Qantas 380 that led to an engine explosion.

It is a cordial, "adversarial" and a negotiated diminution of safety.

Last edited by Lyman; 25th Sep 2011 at 15:40. Reason: bolding for Doze, emphasis the schedule varies per Reg
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Old 25th Sep 2011, 15:24
  #987 (permalink)  
 
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@CONF

I was referring back to "The DC-10 Case", where it states that an AD to replace the cargo doors would have resulted in the grounding of all DC-10s until the repair had been carried out. Perhaps the rules have changed since then, but that was my source material.
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Old 25th Sep 2011, 15:26
  #988 (permalink)  
 
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1. Do Airbus flight controls use artificial feel units?

2. If they do, how would it behave in a scenario with unusual airspeed readings, like AF 447 had? Because an AFU needs airspeed input right?

3. Is this of any significance?
Like dozy already answered modern airbus don't have artificial feel, A300/310 had.

IMHO this accident wolud NOT have happened with artificial feel.
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Old 25th Sep 2011, 20:42
  #989 (permalink)  
 
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Originally Posted by mm43 View Post
The direct link to the January 2011 Airbus Safety First magazine is here.
Finally got around to reading this - despite the occasional endearing translation error it's good stuff and surprisingly makes the AoA situation (which I must confess confused me when described in raw numbers) understandable to a maths/physics dolt like me.

On another note though, it does rather put a spoke in the wheel of those who are saying Airbus/BAE/DGAC are trying to sweep the issue of AF447 under the rug by blaming the pilots, because in the article Airbus come out and directly state that the previous procedures (which they helped develop) were inadequate and in some cases could make a developed stall worse - in short, they're admitting - in print - that they, along with the rest of the industry, screwed up to some degree.
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Old 25th Sep 2011, 20:51
  #990 (permalink)  
 
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This seems a rather difficult 'take away'.

If the control column does not provide the
needed response, stabilizer trim may be necessary.
However, excessive use of trim can aggravate the
condition, or may result in loss of control or in high
structural loads.


How do you deetrmine the limit before it becomes 'excessive' ? Couldn't an easier rule of thumb be devised ? A simple instruction to check trim seems a more natural starting point.
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Old 25th Sep 2011, 20:58
  #991 (permalink)  
 
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If the control column.........
What control column?
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Old 25th Sep 2011, 23:22
  #992 (permalink)  
 
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You're quoting from the "generic" recommendations, i.e not Airbus specific (the clue being the word "control column" as opposed to yoke or sidestick). I suspect the FCOM information per type will be more specific about how the trim should be used in that situation.
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Old 26th Sep 2011, 02:10
  #993 (permalink)  
 
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On 22 Sep/page 49 mm43 kindly posted the link to the Airbus Safety First magazine, with a follow-up link on page 50 by DozyWannabe. Thanks to both.

My reading of it has stalled (geddit?) at Issue 11, page 9, at the oh so simplistic stall condition & effects diagrams. They have been, of course, put together by Airbus, who IIRC only make one high-engined aircraft, the rest of their engines being underslung.

All well and good, but as happened on my initial 320 endorsement, people new to type will have come from low, on-longitudinal-centreline and high mounted engines, all of which require different stall recovery techniques, the range of which which these diagrams don't address.

At item 10, page 9, it is states that "

This generic procedure will be published as an annex to the FAA AC 120.
This new procedure has been established in the following spirit:
)- One single procedure to cover ALL stall conditions
)- Get rid of TOGA as first action
)- Focus on AoA reduction.

Bearing in mind that there will be strong recruitment pressures on airlines, and a probable need to accept less experienced aircrew, to cement the first item of this 'generic procedure' in legislation strikes me as a form of engineering conceit bordering on hubris, and will certainly bring with it deep industry-wide problems in the future.

Personally, I would require all trainees have to be exposed to the Victa 100 (not the higher powered versions, which were heavier on the controls) and be able to demonstate a continuous series of three loops without inducing stall buffet at *any point of the loop. It can & will 'bite' at *any speed and/or g-load if mishandled, and breeds a deep knowledge of airfoil behaviour that sticks with you. Cheap insurance. Oh yes, it also develops a fine 'touch', a la Gums early observations.
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Old 26th Sep 2011, 11:58
  #994 (permalink)  
 
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Originally Posted by JenCluse View Post
My reading of it has stalled (geddit?) at Issue 11, page 9, at the oh so simplistic stall condition & effects diagrams. They have been, of course, put together by Airbus, who IIRC only make one high-engined aircraft, the rest of their engines being underslung.
That isn't quite correct, the Airbus magazine report is just one publication of the outputs from the FAA Stall Recovery Training Working Group. That included at least Airbus, Boeing, ATR, Embraer and probably some others too.

Some non-Airbus reference:

Flight Path Management (Expanded Version) | Flight Safety Foundation
Stop Stalling | Flight Safety Foundation
http://flightsafety.org/asw/apr11/asw_apr11_p46-49.pdf

Yes, the simplistic diagrams don't inspire confidence, given the intended audience, however what is more scary is the conclusion (supported by various documents including from FAA) that the industry has been effectively teaching pilots to power out of a stall rather than put the nose down and start flying again.

This isn't an Airbus problem, and Airbus can only be part of the solution - though at least it looks like something is finally happening across the industry to fix this.
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Old 26th Sep 2011, 13:17
  #995 (permalink)  
 
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IF789: if I may play devil's advocate for a moment.

Even when one is trying to "power out of a stall," one still has to control pitch to prevent restall. Pitch + Power = Performance still applies. Low to the ground, seems to me that there is a risk of negative training taking place if use of power and pitch to unstall isn't well taught.

How the recovery, or return to flight away from stall when one gets a stall warning, is taught is as important as what it taught.
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Old 26th Sep 2011, 13:45
  #996 (permalink)  
 
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It was through Colgan/Buffalo that the more recent concerns re: training to STALL were made evident. Procedure (for an approach/STALL) was to advance throttles, and prevent altitude loss. This was trained as "maintaining back pressure", not increasing it. A loss of greater than 100 feet altitude was considered disqualifying.

And this was accepted training at low level.

Has the common perception of 447's crew STALL procedures been equated with "not losing altitude"? Has it morphed into "full back stick", with the STALL WARN activated for 54 seconds? One believes so, and what an outrageous position to 'push', absent full disclosure of all data.

At the last, when Captain suggests a Pull, ('Tire', in the French), pilot flying says, essentially, "I have been pulling back a long time already".
Without further elaboration by the investigators, this translates as an incorrect reaction to STALL. It most assuredly was not, since no recognition of STALL is demonstrated.

I suggest that leaving it at that, (as a non-response to the airframe's attitude) is grossly misleading, and infers a knowledge of the situation that either is non-existent, or, more likely, not released.

Here we bump into the most telling failure of the current "Investigatory" paradigm. With knowledge of problems in accepted procedures seemingly available, but 'hidden', they are not addressed, and the professional community is at a loss to make progress.

For fear of embarrassing an airline? An Airframer? This is unacceptable.

A profoundly important opportunity to increase knowledge and improve safety exists in the full and complete disclosure of 447's data. BEA are sitting on it. BEA make flying less than safe. It is my charge.

No, call it an accusation.
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Old 26th Sep 2011, 15:37
  #997 (permalink)  
 
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It doesn't matter what the response was, the fact is that they *were* stalled, and as part of the investigation (bolstered by the ColganAir accident), they discovered that approach to stall procedures and training were inadequate for dealing with a real stall.

Will the Asseline fanclub please explain to me why they are not also demanding the same release of raw data from NTSB and AAIB investigations as a matter of course?

@LW_50 - we've been through this many times before, so I'll keep it brief, but if the PF either did not hear or did not properly comprehend the PNF's callout of "Alternate Law" at the start of the sequence, he may have been subconsciously relying on the Normal Law protections to keep his AoA out of the danger zone.
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Old 26th Sep 2011, 15:58
  #998 (permalink)  
 
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Indeed, I believe PF was in "Normal Law", figuratively, if not actually. In fact, It seems consistent with the rest of his flying, this 'reliance' on the a/c's Laws. I keep in mind that turbulence alone could have augmented his "shaky" stickwork; no one here has the chops to say this "mayonnaise" was indicative of poor flying. Bear in mind that Overspeed was his working hypothesis, and we know that can work in NL. So can the autopilot dropout in Normal Law, and remain so...... If he had Overspeed on his mind, and Normal Law as his mien, that would explain alot.

Someone has not considered how much the remaining data can add to the discussion about which he has made some remarkable conclusions. And this particular one not a pilot, as it were.

Dozy, the poor attempt at humor comes across as mere snark, and is beneath you.

"It doesn't matter what the response was...." That may be the single most salient remark in these 6 threads, all respect.

Last edited by Lyman; 26th Sep 2011 at 16:29.
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Old 27th Sep 2011, 16:43
  #999 (permalink)  
 
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Dreamliner drill...

Try Before You Fly: How Dreamliner Pilots Train Without Lifting Off | Autopia | Wired.com

"Anyone who's flown a Boeing 777 can get up to speed with the 787 in as few as five days as the two airplanes share a type rating for pilots. A pilot with no experience in a Boeing airplane will need as long as 22 days to receive a type rating and master the 787."

Just wondering about the relationship between sim training and that "human factors" problem...

Disclaimer: Im not even remotely trying to put this in AB vs Boeing perspective.
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Old 27th Sep 2011, 20:28
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I think it is possible to get to sophisticated about the 'human factors' problem. It is all very well talking about isolated detail (sidestick v yoke, angle of attack meter display), but I think the real underlying issue is the pyschological response which seems to have determined that something inexplicable was happening. In a straightforward, known, simple, deterministic system which you know doesn't embody millions of man hours of design, coding and testing, there are relatively few parameters and few possible control responses. The mental approach to problem solving in such a regime is happily constrained. In a system which you know (all that training, all those sub-modes, all those interactions and dependenciess to remember) to be complex, starting to understand the problem is polluted by the possibility that the complex intervening layer is behaving in a way which you either don't understand, or which has bust and gone outside its normal limits.

It doesn't require the complex system to in fact break, or for you to forget your training, to introduce the possibility that a stressed human mind trying to start to appreciate an unanticipated possibility never achieves sufficient confident to diagnose and then act. The awareness of a complex intervening layer is in itself sufficient to frustrate intelligent problem solving, at least in a timely way.

A 'big red button' which forced direct law, with direct law behaviour a set of memory items, would seem a reasonable last resort to offer a bemused crew.

Not forgetting appropriate display of unusual trim conditions and cancellation of any warning cancellations, naturally.
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