IF789,

We did switch 2 ADRs off in order to degrade to Alternate Law.

As always, on the Bus, the less you touch the stick the better you fly.
We had no problem with the roll, but did the practice with no simulated turbulence.
Overcontrol and following oscillations can be easy depending of turbulence level.

The sidestick has that particularity, even in Normal Law, to easily, and well unvolontary, induce some roll when full back or fwd stick is applied. It is noticeable when conducting a GPWS procedure.

Clandestino
The control power of the THS is not what we are interested in so much as the effect of trimming all the way up to the stall. Test pilots avoid doing this for good reasons.
It is difficult to get the aircraft out of a stall when it is trimmed right up to the edge of the stall or beyond, particularly with a THS type aircraft.

Do you really think that just because the aircraft functioned just the way the designers set it to do in some obscure corner of the envelope, it is perfectly OK?

Autotrim - yet another red herring in search of a barrel to join its other compatriots. The evidence from this accident points to human factors, nothing more/nothing less. It isn't about the technical aspects or how the machine functions but what caused two supposedly rational beings to function the way they did. It's internal not external which seems to be missed by so many posters.
I have mentioned this before - KNOW YOUR MACHINE or professionalism. This was drummed into me by my flight trainers. No excuses - these pilots did not know what to do and this caused the accident. It seems to me that for some commentators the unthinkable is that the flight crew could have reacted as they did. Unfortunately that is the reality and grasping at straws doesn't help. There was nothing wrong with the aircraft but everything wrong with the human reaction. Try to focus on this ladies and gentlemen and the discussion will be much more fruitful.

"nothing wrong with the aircraft" hmmm I seem to recall there was a string of ACARS messages and errors including UAS, reversion to Alt 2 Law and other aircraft issues...

The aircraft performed as it was supposed to and the control system did the same. It responded to the UAS as it was designed - it was the crew that didn't respond appropriately. Remember, the aircraft stayed in level flight within the parameters of its designed flight envelope. It was the PF who put the aircraft into a stall.

The aircraft would have continued flying within the flight envelope - it was not in a dangerous state. You should go and reread PJ2's comments (on one of these myriad threads) on doing nothing. As a pilot one evaluates and then acts. One does not act and then wonder why things go wrong. One scans ones instruments, absorbs the information then in this situation pitch and power.

Now this is not about 'crucifying' the crew it is about understanding why the accident happened. The simple fact is that it was the crew who put the aircraft into the situation where it crashed - nothing else. The following points pertain; CRM, training, crew knowledge of SOPs, lack of knowledge of the machine, airline culture. All these combined to cause the accident in what was a survivable situation. This is the simple fact of the matter, if one assigns responsibility one has to look at the crew and the airline and its procedures.

Some time ago I wrote that the airplane's pitch and power at A/P disconnect was consistent with AP & A/THR maintaining altitude and speed while flying in an updraft of approx. 1000 fpm. It would have continued in those conditions as long as the updraft lasted. After leaving the updraft, it would have descended at 1000 fpm at the pitch and power and airspeed it had at A/P disconnect.

P.S. The above assumes that the FCPC maintains pitch after AP disconnect and leaving the updraft. If it maintains 1g, it would need to restore the still-air pitch of about 3 degrees nose-up, and the airplane would then decelerate at about 1 kt TAS per second at constant altitude.

I've just read a different thread on this accident and it threw up one big question for me. A lot of people seemed to kept mentioning deep stall (as this is also what the media called it) however was it deep stalled or just deeply stalled? Two very different things. Some people on the other thread seemed to have as little understanding as the many articles you can read about it.
Can an airbus even deep stall? Aren't ALL aeroplanes that can meant to be fitted with stick pushers? or is that something airbus could have got around?

Thanks :)

@Flight Instructor
Stall (flight) - Wikipedia, the free encyclopedia

For some people 'deep stall' is synonymous with 'locked-in stall' i.e. a condition that cannot be recovered by normal use of the flight controls. For others it just means deeply stalled.
"Can an airbus even deep stall?" Several 'experts' on this forum doubt it. The response of the airplane to slight relaxation of the pull on the SS seems to indicate that the airplane would pitch down with a determined nose-down input.
The stalling characteristics requirements apply with all systems functioning as designed. In the case of the A330 that means Normal law, which does not allow the airplane to exceed the stall AoA, and can even effectively act as stickpusher as demonstrated in QF32. Alternate law is a failure condition that is judged on the basis of its probability of occurrence and the ability of the crew to handle it.

RetiredF4 wrote (post 1633): “I´m interested in the "why", and as anybody can have a reason to do something or to don´t do something, the answer might be in the interactions of PF input and AC reaction as felt and understood by the crew.” (Re why did the PF pull back into and keeping the stall.)

Unless BEA release more CVR data or an analysis of that plus other data, I doubt if we will ever know for certain, but early on in one of these threads, there were at least two theories put forward by others:

1. Initial pull inadvertent, while “stirring mayonnaise” trying to control roll. PNF was telling PF to be more gentle with the SS, (but PF took little or no notice?).

2. Soon after, however, PF was evidently doing it on purpose. Possible reason – he thought they were overspeeding, and was trying to raise the nose to correct this. (If at the same time as TOGA, this seems to me inconsistent thinking on his part – but comments like “see the crazy speed”, later “I have been pulling up most of the time”, and reported high noise level which a witness is rumoured to have heard on the CVR playback suggested to some that he confused stall and downrush noise at high AoA with overspeed noise, probably never having heard either before. Didn’t he also try brakes, until PNF told him not to? Also, after PNF took over SS control briefly and stopped pull back, PF resumed (without the mantra “I have control”) and pulled back again, AIUI. That had to be deliberate, and not agreeing with PNF’s apparent belief that it was not overspeed.

(These were the tentative conclusions of ATPL’s – I am simply recalling them.)

These are the reason I mentioned that when a stressed pilot forms the wrong conclusion, he/she tends to stay with it regardless of ineffective attempts to correct the wrong problem, in my post 596 on the “final crew conversation” thread on R&N.

deeply stalled
 

As posted way back, at least one jet I flew had a true "deep stall" in which recovery using conventional control movements was not possible. I even posted the graph of pitch moments. The good news was unconventional control applications could "rock" the jet outta the deep stall.

I can not say if the AF447 jet was in a true "deep stall" without seeing the pitch moment charts for its c.g. and AoA. I would say the thing was "deeply" stalled and held there due to pilot inputs and the trimmed stabilizer that reduced nose down authority.

As another contributor posted here a day ago, a similar condition in the sim was overcome and he flew the plane out of the stall.

I put great faith in Hazelnuts' analysis. The problem is in accepting it without further questions. The a/c's actual vertical speed was 1000fpm?

At the moment of a/p disconnect, does PF sit on hands? He has a Roll to the right to contend with also. Does he resist the urge to "Have the controls"? Because that means touching, and handling. Why touch and risk the displacement of the stick, if the book says 'don't touch'? Or, "Do not maneuver"? Sophie's choice? An after the fact pronouncement on an anonymous forum doesn't qualify as SOP.

Further, let us entertain that the a/c has not "settled" on 1000fpm, but was in some trend, and the PF felt, and understood the g forces to his satisfactory conclusion? Right or wrong, he is now 'seat of the pants', and that might be a bad thing. We know he is inconclusive about accel cues and audio feedback in the flight deck. In his own voice....

Was his flight path the result of a risky blend of poor memory/training/experience in hand flying with some 'cheek' input? TTex has posited armrest misplacement, and is it possible to believe that PF never got the chance to fasten his restraints after a conversation or other? The only clue we have of his re: stick work is his "I have been pulling for a while".

In the 5-10 seconds of loss of autopilot and manual acquisition, the die is cast. Following this 'potential' conclusion, we have examples of literally dozens of holes/cheese. My contention is that from this early point, the cheese was mostly hole, little cheese.

I'm not sure where you see this ?

What I do see at AP disconnect time is a selected negative vertical speed of 5000ft/min and a vertical speed going in that direction (the quality of the given traces is somehow poor ...)
I also do see a pitch at zero (that's 3 degrees below the usual cruise pitch)

If what I do see is reliable (?) the initial action of the PF to pull is totally justified.

HN39, how would you justify the AP/FD vertical mode trace is not published ?

At no time in two years plus has anyone questioned the NU input of PF at handoff. Only insofar as he should have left the a/c descending at 3 degrees. Have I missed something? This has been the position all along, the a/c needed handling.

The ND reflects A/P reaction to substantial UpDraft.

The politics of the initial BEA report reflect the wisdom of the PF's pull.
"The a/c did not initially respond..." It is their way of throwing PF and the a/c a bone...... The resultant climb, when it occurred, had the benefit of the airmass, and in AL2 should have trimmed NU. It did. Six Degrees? The 1.65 g was the result of these factors, not the pilot acting alone.

The jet was manouvering at a/p loss, and can be considered to be Upset, at this point. LOC came later. Twilight Zone, anyone? ffs.

An opinion can be put forth that this a/c was uncommanded for as long as 5 seconds. That qualifies as Upset.

How sinister is the creep of Urban Myth.

If you are referring to the 'zipper' trace on page 111, I don't see any effect of that on the airplane's behavior. If you look at page 42 you'll see the AP maintaining altitude with very small variations of V/S due to the turbulence that is more explicit in the trace of normal acceleration. I explain the pitch of zero (that's 3 degrees below the cruise pitch in still air) by the autopilot pitching the airplane down to maintain altitude in a somewhat stronger upcurrent that commences at 2h10 (*). Pitching the airplane three degrees down in still air would change the FPA three degrees down, i.e. result in V/S=-1000 fpm. To prevent the airplane from accelerating on the downward flight path, the thrust must be reduced. The A/THR appears to do just that, although it doesn't quite reach the level required for that FPA (page 113).

That may be so, I was only answering a question.

I have no opinion on that, except that its omission in the interim report probably means that the trace does not provide significant information.

(*) That 'somewhat stronger' updraft may well be responsible also for the rolling motion and for the very particular type of ice particles (crystalline structure, particle size, density) that clogged the pitots of AF447.

Remember that could also just as easily be an "invalid value" rendered as the lowest possible value in range by the graphing software. I'm not arguing it's definitely one thing or the other, but given the aircraft's actual trajectory I'm inclined to think it's that. Given that it occurs prior to AP disconnect, I'm also inclined to think they'd have noticed and pointed out flickering values on the FMS display if they'd seen it as there wasn't much else going on in the flight deck at that time.

Deep Stall? She came close a couple times to a smart recovery. Deep is a misnomer.

Clandestino: "The a/c wanted to fly." I agree, and there was airspeed available, just a too high AoA. The Stall entered unconventionally, and any recovery would have been the same. How many Stalls have been recovered in type? In these conditions?

Most pilots don't put it in a stall condition when they have a simple loss of airspeed and an autopilot disconnect. They have the experience to know what to do.

I am surprised to see this thread go soo long. The simple answer is power and pitch, the varible being TC's.

Can someone explain clearly why the BEA released only excerpts ?
Is there a law that prohibits the BEA to release the entire FDR ?
Is there a law that prohibits the BEA to release the entire CVR (transcript) ?
If there were leaks in the press and the publishing world (Otelli) BEA can only blame himself
If the BEA would provide comprehensive and clear informations (instead exerpts) .. journalists would not have to resort to some practices for gather informations (leaks)
Hide informations from the public .. how it's called ?

Retired F4, those remarks I made are not in any way personal and are absolutely meant to be general - i.e. applicable to anyone. I am sorry if you felt offended but here the offence is strictly in the eyes of beholder. Most of your questions have already been answered, too bad that besides having open mind, answers also require considerable foreknowledge of matters aeronautical to be understood. Somehow I don't think the answers given don't support the theory of "making sidestick input based on G feel".

Can we agree on that bending the facts to suit pet theories is not bound to be particularly productive if our aim is to truly understand what really happened?

The only thing I found in your post that has not been answered yet:

Airbus FCOMs & AMMs, 2.5/-1G clean.

I have absolutely nowhere stated that I've found the reason for AF 447 catastrophe, claiming that I wrote so is severe misinterpretation. I've put forward theory I think currently fits with the facts as we know it. If anyone have a facts that are contrary with it, please post it, it's not about proving my or yours or anyone else's notion. It's about finding what is right, not who is right.

If this investigation gets wrapped up with "Pilot pulled for reasons undetermined" that would be a real failure. What made him pull must be brought to light.

Who gives a part of a rat that the tail is attached to about what I think? This is the way our local universe, with its laws of aerodynamics, is structured. Yo want to go fast, high, far and heavy? It's a no-go without powerful THS. DP Davies book "Handling the big jets" has excellent treatise on why we need powerful stabs and how to handle them. Brief summary:If you suddenly got an idea that the aforeqouted sentence somehow validates your notion that autotrim is lethal, a) perish the thought b) read the following sentence. Theorizing about particular features of any design without knowing and understanding the basic principles behind it is extremely unlikely to be meaningful. Not limited to THS. Not limited to aviation.

My apologies, I keep forgetting that these are open fora so I have to keep discussion dumbed down to high school level for everyone to understand. You seem to understand that my statements "I do not fly by feel" and "I try to fly smoothly" contradict. Well, it is just not so. I do try to fly smoothly but not by the seat of the pants but by making small, measured inputs and crosschecking their effects against that big, bright attitude indicator in front of me. Leveling off without lifting the pax off their seats is best done by making small pitch change rate and that is done by looking primarily at the attitude indicator, crosschecking with altimeter and vario. Definitively not by using vestibular sense - it is last guard telling you you're doing something wrong but inflight it cries "wolf!" too often. Every instrument rated pilot must know the technique and use it, especially those who made it to widebodies, e.g. Airbus 330.

I would suggest reading Edgar Allan Poe's "The Purloined Letter" for an answer to that.

Not much is hidden, especially not the salient parts. The inability of some to recognize what is in plain view is quite ordinary but combined with their penchant for airing conspiracy theories gives spectacularly amusing results.

Hi,

Clandestino
Salient parts are only parts of the truth .. not the entirely truth

Condorcet
Paradoxally

Clandestino
Are you sure that the facts you know are all the facts that know the BEA ?

"What made him pull must be brought to light."

i think it will never be. the pilot will not tell you why he pulled and any data recordings can only answer what he did, not why he did this.

Hi,

The actions of a man (supposed normal mentally) are always the results of a thinkink
To make this thinkink that will lead to his action he must have facts to analyze
Recordings (voice and datas) can show what facts he had
If his actions are inconsistent with the facts available to it .. one might conclude that his thinking was not good, or as a last resort .. it does not have all his mental faculties (were altered) during the thinkink
So .. if we have all the datas who were available to this pilot .. we can conclude if is thinkink was good or bad
So .. yes we will know "why"
It's only three answers to "why"
Bad thinkink
Good thinkink relying on bad datas
Mentally disturbed

Hi,

Maybe it was already explained in many messages ( I don't remember anyway)

http://i.imgur.com/EEhhF.jpg

Why this difference of (displacement) movement of the elevators in reaction of pratically same movement (displacement) of the SS ?
Seem's that in the first 20 seconds .. the SS movements have not perceptible effects on the elevators ....

At a rough guess, I'd say as the airspeed goes down, the greater the potential deflection of the elevators to match the orders being issued from the sidestick...

Hi,

DW
So the deflection shown by the elevators is not the direct result of the position of the SS but instead .. (a filtered order) a position commanded by computer orders in relation with the speed
That can be weird .. as we know that the problem was a unreliable speed due to pitot tube problem ....

BEA have quantified that. They have not established a reason for it, however. I believe the THS was moving, though. "Initially the a/c did not respond"...

Uhm, no. There's a control loop feeding back the a/c response to the FCCs. No weirdness involved.

I suspect they're using different inputs to work out the aircraft trajectory/velocity than air data, otherwise there's no way that Alt 2 would work with ADR DISAGREE. In fact I suspect that the data they're using to work it out (probably inertial) formed the basis of the BUSS design.

Looking at the selected vertical speed trace, one of the key thing I'd like to check is the AP/FD vertical mode trace - I personally do find it disturbing it is not published yet.

HN39, how would you justify the vertical acceleration trace in the Perpignan case has never been published ?

@JC:
 

It was explained before.
During the first part the actual normal acceleration (Nz) was > 1G and during the second part the Nz was < 1G.

Old Carthusian,
Your mantra is KNOW YOUR MACHINE but in the meantime don’t want to hear about technical stuff … ?

Equation is simple : If a type is repeatedly exposed to unreliable airspeed indication at cruise flight level, the manufacturer has to be aggressively proactive by publishing at least a safety bulletin addressed to all operators with a clear procedure to be followed if needed and to recommend all operators to train their crews for such eventuality.

When you have practiced once you are so much better equipped.

Every Boeing I flew had an unreliable AS chart for weight and altitude to hold a pitch setting and power setting. What these pilots did when they lost AS and autopilot was not anything remotely close to what the Boeing chart says. Everybody knows you can't pull up over 5 degrees at 35,000 ft in an airliner and still fly.

Unfortunately this is the new way of hiring pilots out of flight schools with no experience. We still have plenty of experienced pilots but they won't work for2,000 per month.

I know they were flying an Airbus 330 but the attitudes to maintain level flight are about the same. I went out of my way in my career to only fly Boeing AC. Had to fly MD80's for a brief period but that was just so I could marry my now wife of 21 years because of geographical problems flying the 727.

CONF iture

If you bothered to go back and read the previous threads (around 3 or 4 I believe) you would find a discussion of Airbus' procedure for UAS. It existed but wasn't used or even consulted in this case. The question is why? A stall warning was ignored for a very long time, again why?
This is not the fault of the manufacturer as much as you may wish it to be. This accident is a result of the actions or lack of them of the Flight Crew, nothing more and nothing less. The important thing to examine is what led the Flight Crew to act in the way they did and then to consider what can be done to avoid future occurences.
The suggestions that somehow you can attribute the accident to the autotrim or the lack of a yoke do not conincide with the transcript of the CVR or the FDR. They are missing the point which is psychological. This ironically is more difficult to understand than simple mechanics and aerodynamics. However, we may postulate what led the PF to take the course of action he did but we will never know for sure. The one thing is if this accident induces AF to improve its training and procedures the loss of life will not have been in vain.

CONF iture; I don't recall having particularly missed it when reading the report. Anyway, this thread is about AF447.

The response of the airplane in the first minute is shown in high resolution on pages 41 and 42 of Interim #3. Something odd struck me in the 'simulation' traces on page 42. According to the associated text, "it was agreed that, initially, the simulation would be confined to the longitudinal axis, without introducing turbulence." If the simulation is without turbulence, what caused the variations of alpha prior to 02:10:05, without noticeable variations in pitch, V/S and Az, and why did the elevator move after 02:10:00? Why differs the THS position from that recorded?

It is good observation HN39.

• Also why simulated elevator position shows signs of oscillation movement already before 02:10:00 ?
• Why that time period is not represented in page 41 graph ?
• Why only left elev is represented ?
• Do left and right elevators really move together or graph on P108 could be better … ?

"Airbus conducted a simulation of the aircraft behaviour based on the theoretical model and on the actions of the PF (sidestick and thrust)."
Why not then represent PF's actions (sidestick and thrust) on those P41-42 graph ?

Correct. But investigation led by the same investigation body and again some data of interest are not published.

In a few words :
Why does the Judge withold data from the proceeding ?