roulishollandais

to replace post #956

information about Rapaport/Otelli sources

In the Rapaport book (in French) with Forword from Jean-Pierre Otelli (page 7), Altipresse editing is Otelli editor, maquette couverture : Bastien Otelli, Traduction En --> French : Frederic Marsaly, Révision (sic) : Laurence Gay & Germain Chambost, many informations are credited to Colonel Xavier Mulot of the GTA (Gendarmerie des Transports Aériens) former commanding of the Section de Recherches de la GTA, he was since demissioning.

The Section de Recherches de la GTA is in charge of the aviation accidents investigations working for the Ministère des Transports (BEA) who gives him orders, and not the Ministère de la Défense. PAF is another service concerned with aviation for the Ministère de l'Intérieur, and to forget nobody the Gendarmerie de l'Air, who gets orders from the Ministère de la Défense. Only the GTA is concerned with aviation accidents.

Sources of Rapaport/Otelli book page 222-223 fr with Col XAVIER MULOT are :

Chapitre1 (LES VICTIMES )
entretien de l'auteur avec le Colonel Xavier MULOT, Roissy-en-France, New York Daily News, 11juin 2009. (Xavier Mulot était à l'époque un personnage central de l'enquête. Il s'agit de son seul entretien avec un représentant des médias. Il a depuis démissionné de son poste.)

Chapitre 2 (L'ENQUETE)
{...}
Entretien de l'auteur avec le colonel Xavier Mulot, Roissy-en-France
{...}

Chapitre 9 (UNE AFFAIRE CRIMINELLE)
Entretiens avec le colonel Xavier Mulot

Special thanks from Roger Rapaport to Jean-Pierre Otelli are p.248 fr (june 2010)

They are no reference to an English version of the book.
The French book is ISBN 13:978-2-911218-84-2 from november 2011
and EAN 13:9782911218842
with all rights for traduction, reproduction, and adatation reserved in all countries.

roulishollandais

Who said that ?

Roger Rapaport ref to PPRuNe are :

page 168 : (Une guerre législative de trente ans)
"Ce point de vue est partagé ar un pilote de ligne qui a écrit sur le forum des pilotes professionnels PPRuNe :"Supposons que quelqu'un se soit approché du mécanicien de Continental et lui ait dit que s'il installait la barre métallique de façon incorrecte, elle allait tomber. Et que peut-être elle allait tomber sur la piste. Et que..."

page 185 : (3.april 2011)
"L'histoire de la recherche du vol Air France 447 faisait les gros titres de Papeete à Philadelphie, de Bogota à Bangalore. Sur le fil de discussion consacré au vol AF447 sur le forum PPRuNE, les dernières théories faisaient l'objet de vifs débats entre des pilotes et des expertsaéronautiques assis devant leur orinateur, leur portable, iPad ou Smartphone dans le monde entier."

CONF iture

1) To work properly, automation and protections need reliable data.
If data are known to be corrupted the simplest thing to do would be to cancel automation : Direct law - No autotrim
Every Boeing pilot flies that way in manual flight, is it an issue ?

2) ALT LAW + Autotrim amplify the severity of the stall.
Sidestick neutral, the THS would have rolled the same way.

Same reply that 1)
The conservative approach would be to make sure that automation stays out of the way when data are identified as unreliable.


PS : Thanks to both of you for you reply.
It is unacceptable the BEA simply ignores the matter.

TTex600

CONF, I concur with post #964.

DozyWannabe

Not true (ref: Birgenair, Flash Airlines, Turkish 1951 among others).

Remember that Boeing pilots trim manually regularly, whereas FBW Airbus pilots do not. At which point the question must be asked whether a drop to Direct Law - in which pilots are expected to trim manually despite it not being part of their day-to-day operational habits - would be more risky than less.

Failure modes are intended to reflect as close to the normal systems behaviour as possible, not some nebulous definition of what constitutes "real piloting" and what does not.

Only if the pilot makes and continues to make inappropriate inputs.

Not true - or your definition is too loose. If sidestick was neutral from the beginning (i.e. if the PF had not commanded an inappropriate climb and 15 degree NU pitch angle) then autotrim would have never commanded THS to an extreme angle.

They don't - the THS angle in response to PF input is noted in detail. It is not for the BEA to derive conclusions based on that unless autotrim behaved contrary to design.

Organfreak

Really??? That doesn't sound right. Could you cite?

DozyWannabe

When a Boeing aircraft is under manual control, the pilots must trim using the wheel.

This is not the case for manual control in a FBW Airbus, where autotrim is active in every control law above Direct.

Airbus Flight Control Laws

Of course, if the Boeing pilots are using Otto from wheels-up to flare, then the definition of "regularly" must be qualified with "when under manual control"

The important distinction is that in training, any manual control segment in a Boeing will require manual trimming, whereas this is not the case with the FBW Airbus types.

[EDIT : Of course, what CONF iture is not stating is that manual trimming becomes more effective with backdrive, so his call for an immediate drop to Direct is less a safety concern than it is a way of servicing his objective of forcing Airbus to go back to back-driven yokes as a PFC. ]

Organfreak

Again, I ask you to cite, please.

DozyWannabe

What do you want me to cite? It's common knowledge!

jcjeant

It seems to me that flying a airplane manually (without the assistance of automation) requires that the pilot use the trim manually
This is certainly what all airline pilots make when piloting an aircraft non equipped with automation
Is that the pilots of Airbus airplanes or other brands equipped with automation have no longer know how to fly a Cessna 172 ?

DozyWannabe

And that's an opinion you're welcome to, but that doesn't make it correct.

Which has nothing to do with aircraft designed differently. This is what I meant by a "nebulous definition of what constitutes "real piloting" and what does not".

Well, one would hope they know how to - but they fly it differently than a FBW Airbus.

As I said though, manual trimming is a lot easier with feedback (either direct or artificial). Autotrim grew out of having PFCs without dynamic artificial feedback, and as I said to CONF iture, it behaves perfectly well as long as the inputs make sense. Perhaps it should be made more explicit that in Alternate Law, the PFC controls the trim as well as the elevators, but that in itself is not a bad design.

henra

The problem with that is that it conflicts with the principle of the sidestick. You would need force feedback into the stick to make it viable. Otherwise it might cause harm rather than doing any good.
That would make the installation more complex and add another possible source of failure.
It is always difficult to judge what is the more dangerous approach.

The main drawback of the classic yoke of FBW Boeings is probably weight, cost and mechanical complexity. It is a hell of a mechanical device just to tell Otto what you want him to do. It is like Joystic deluxe...

TTex600

Make sense to who, or better said, to WHAT? In this accident we have an aircraft designed to be flown by computers that suffers a GIGO computer issue that convinces the computers to give up on their job. Which leaves the pilots with a system designed to be flown by computer and they now have no computer or at least not all of the computer. BUT, it still wants to be flown like it is a computer because only PART of the computer system gave up, the rest is still working and it only knows computer sense.

I ask again, make sense to who or what?

Forgive my english/grammar, Texan is my native language and i'm in a hurry.

DozyWannabe

Not so - the Airbus FBW series were intended to be no more reliant on automation than any other contenporary type.

See Birgenair for an example of what happens when the automation does not know when to give up...

See my first reply. The system is not designed to elevate the computer over the pilot(s) and never was.

Again, no - it wants to be flown like any other aircraft, with the caveat that the trim is automatic. In such circumstances, the only thing that needs to be remembered is that the trim is affected by the PFC inputs - if sustained for long enough.

If these pilots went straight from instrument rating to ATPL - and their ATPL experience consisted entirely of Airbus FBW types - then autotrim is the norm. The habit of trimming manually grew out of technical limitations of aircraft of the postwar period - it does not necessarily follow that later designs should mandate manual trim when the flight management automation disconnects.

CONF iture

No.
The Airbus flies already very well under Direct Law, and manual trim is part of that direct, just like the Cessna, or the Airbus 310, just to please DozyWannabe who don't like me to name the B.

DozyWannabe

Er, I don't give two hoots what you name or don't!

It flies just as well under Alternate Law - and unlike the Cessna, A310 or Boeing, manual trim is more difficult because - as has been said - there is no direct or artificial feedback. Of course, this is a moot point for you, as doing away with the decoupled sidestick has been part of your agenda from the beginning...

CONF iture

You have no experience.
You say you have no experience.
But you keep writing as you were loaded ...

CONF iture

Remember : Quote if you want to put words in my mouth.
Didn't know I was that powerful either.

DozyWannabe

I write based on input from those who are experienced (and crucially have shown no sign of a political agenda).

And I trust other readers to be able to look up your previous posts - in which you have repeatedly shown an opinion that you feel decoupled sidesticks are a bad thing.

Along with statements like:

Which imply that the majority of pilots were against the sidestick concept (untrue) and also imply that pilots were not involved in the specification of the Airbus FBW flight deck and logical design (also untrue - almost insultingly so).

All of which are in the first page of search results, and all of which are based on nothing more than your own opinion.

Lyman

CONFiture..

You say... 2) ALT LAW + Autotrim amplify the severity of the stall.
Sidestick neutral, the THS would have rolled the same way.

I cannot prove it but I do not think the THS made the STALL more severe, so much as it made the STALL Entry different...., taking away the two cues an aircraft must retain to warn of STALL with the airframe. Without Trim, the a/c likely would have STALLED prior to power and lift ceilings, instead of after, so the a/c started its descent with the nose held high, having transitioned to fully Stalled with no change in Angle of Attack, and the slow loss of the remaining lift occurred due momentum, not loss of lift, nor power.

Buffet was unnoticed (or confused) because of turb, and also the aforementioned transitional bleeding of lift, eliminating this most necessary warning.

With the combination of THS and elevators, I believe the tail kept the nose up through the STALL, and beyond, foreclosing the a/c natural tendency to descend at the break....with no THS the pilot may have lost tail authority sooner, even with full NU, without the THS. He might have encountered secondary STALL with his persistence, but he would have had to ignore the NOSE drop...