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AF 447 Thread No. 12

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AF 447 Thread No. 12

Old 13th Aug 2014, 17:27
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Originally Posted by Linktrained
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.
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Old 13th Aug 2014, 17:58
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Commercial Aviation Accidents 1958 - 2013

A Statistical Analysis
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Old 13th Aug 2014, 19:05
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A33Zab - Nice summary. Thanks!
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Old 13th Aug 2014, 21:34
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Originally Posted by DozyWanabee
@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.
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Old 13th Aug 2014, 22:23
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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

Last edited by roulishollandais; 14th Aug 2014 at 08:36. Reason: 1958 -> 1994
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Old 13th Aug 2014, 22:46
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Originally Posted by roulishollandais
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.
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Old 13th Aug 2014, 22:56
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@roulishollandais

which are the numbers of fatal events of the DC3
source: Aviation Safety Network

Hull loss accidents 2767 with a total of 11744 fatalities.
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Old 13th Aug 2014, 23:26
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@A33Zab
Wonderful documentation
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
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Old 13th Aug 2014, 23:32
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Right, but ASN includes former C-47s in their stats, which makes the ratio of hull losses versus number built difficult to determine.

Originally Posted by roulishollandais
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/...?id=19591019-0 .
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Old 13th Aug 2014, 23:36
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@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!
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Old 13th Aug 2014, 23:51
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Could one assume that a proportion of the DC3 era write offs were due to ignorance, rather than being aircraft type specific ?


No landing aids
Mountain in the wrong place
Lack of aircraft performance data being availability
"Pilots never get tired"
etc. !


The HP42 never injured a passenger in airline service, but would that be acceptable today ?
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Old 13th Aug 2014, 23:51
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Originally Posted by roulishollandais
@DozyWanabee
Point for you, I missed the 1994 page 10/20!
I'm not here to score points, just to try and figure out facts.

It is still worse if the factor 3 of hull losses applies from 1994 to 2013 (20 years) with the new generation of pilots!
Where are you getting factor of three from?
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Old 13th Aug 2014, 23:53
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Test flights

Originally Posted by DozyWanabee
That accident was caused by poor preparation by the airline and very poor decision making by the Captain, not a technological fault.
…due to few in flight tests Airbus procedure by corporate test pilots : was not BZ a "manufacture test pilot" and not independant toward AI? A similar problem existed with the ATPL non-EPNER team : how are you really free to say to BZ "that detail must be modified"?
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Old 14th Aug 2014, 00:01
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I'm not going to get into the Habsheim thing again, but the test flights performed for the BEA were done by Capt. Bechet, who was acting in his BEA capacity and, regardless, was an employee of Air France, *not* Airbus. The report of the investigation Bechet headed was implicitly critical of his employer, so accusations of bias are a little hard to fathom.

BZ had nothing to do with any of it. (And Gordon Corps, who was the "hands-on" lead pilot engineer at the time of testing/certification would likely have been perfectly open to suggestion...)

[EDIT: I think I see what you're saying regarding the "factor of three" - I think you're assuming that the gradual increase in losses of second-gen aircraft is because of a drop-off in basic piloting skills, and if that's the case I think your conclusion is wrong. Bear in mind that those second-gen jets will have been flying for decades by that point (with attendant increases in maintenance issues), and that a lot of them would have been sold off to territories with a poor safety record, e.g. Africa.]

@Linktrained - Almost certainly. I know there's a tendency to romanticise the early days of commercial aviation, but I can't help but harbour a suspicion that if someone were to have offered the modern avionics and flying aids we have today to pilots of Gann's generation, they'd have bitten that person's arm off to have them!

Last edited by DozyWannabe; 14th Aug 2014 at 00:31.
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Old 14th Aug 2014, 00:26
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@DozyWanabee
I was talking about A320 certification flight tests (BZ), not Habsheim investigation from the BEA (Béchet).
3=upper rounded (1.7 / .7) or under evaluating (5.47 / 1.3) (respectively fatal and hl)

@Linktrained
Military and war zone flights may have specific difficulties , I don't think these C-47 pilots died due to ignorance or missing skills, at contrary, but to environment of their flights!
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Old 14th Aug 2014, 00:35
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See above - I've amended my post to include extra details. BZ wasn't involved in the day-to-day work of certification from the Airbus end, that was headed by Gordon Corps - and as I said, I think he'd have been happy to take suggestions on board. Remember that he was a senior test pilot for the ARB - and successor to D.P. Davies as chief - before Airbus poached him.
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Old 14th Aug 2014, 01:14
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in " Les Cow-boys d'Airbus" Author Bernard Ziegler, Ed. Privat Toulouse 2008, p.168 Liste des personnalités

Gordon Corps among 11 Pilotes, with 10 Ingénieurs navigants, 8 Mécaniciens ńavigants, 9 Ingénieurs, etc.
No mention of D.P.Davies...
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Old 14th Aug 2014, 01:51
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interesting similarity

Here is an interesting reconstruction of XL888 crash

https://www.youtube.com/watch?v=uZdk6Td6DNc

See the stabilizer position versus pilot inputs and aircraft response.
Imagine that situation in a visual & instrumental darkness, vertigo and heavy thunderstorm, then you might realize that the question: "But what is happening?" doesn't come from an idiot at all.
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Old 14th Aug 2014, 03:21
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Doesn't matter the type, the PF had to use the manual pitch trim anyway
But, anyone can answer the question: Isn't a software issue having the stabilizer at max nose up position while stall warning is online?
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Old 14th Aug 2014, 04:45
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@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.

You have changed the subject. I have not studied the A320 development enough to be able to spout off datum's about it. Who is disputing its fine safety record?

We get reactionaries in all walks of life, particularly from arm chair enthusiasts here on the internet. We get professionals with differing opinions and things can get pretty polarised. The subject of our original thread drift was about posters’ comments that you nullified using your dubious statistical evidence based on a very small sample base. In my opinion the majority of these posters seemed like professionals with valid opinions developed from their experience. The only conclusion one can draw from your comments is you think these posters are reactionaries. We have differing views.
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