I wouldn´t have used one. It was a pro spin flight control in my stall and spin training. The main emphasis of the procedure is reduction of AOA. AF447 PF concentrated on roll for too long.
The yawing and the problems of the PF to reestablish wings level flight was imho caused by using ailerons at that high AOA.

One interesting paragraph i forgot in the above post, it is from the introduction part and should have been on the top:

Note the thing about tactile feedback.

Given the very high AoA during the descent, it is surprising that the ailerons were effective enough for roll to be (reasonably) controlled. Not much point looking at how well teh PF controlled roll under these circumstances, at least in terms of judging his sidestick touch. Presume the ailerons were acting as drag modulating devices rather than Cl adjusters. Not so very much more and the wing would have been going backwards (AoA >90 degrees).

Interesting quotes though, so thanks again.

AlphaZulyRomeo,

At a re-read of your text, that last paragraph of my post is to be ignored. Originally I was not 100% if my reading of your text was correct, and at a re-read I realize that it was a misunderstanding.

AlphaZuluRomeo

Yes, I was speaking of Alpha protections lost. I was party of a very long discussion on Rudder/Vertical Stabiliser issues long ago, and understand reasonably well the RTLU.

The PITCH is protected "IN" 'g' ? OR "BY" 'g'? Its PROT is time discrete, as it prevents transient exceedance of PITCH loads.

It demonstrably does not prevent high angles of Attack see: "the climb"

In fact, as long as the a/c rotates within a 'g' envelope, there seems to be no functional limit of PITCH UP.

Now here is the problem with that, as I see it.

447 entered the climb without a STALL protection, and STALLED. She climbed at a rapidly inceasing PITCH value, but with a controlled RATE OF CHANGE.

Wasn't PF using 'g' prot as his NORMAL LAW "stand-in"? No immediate and seat crushing PITCH UP, but a steady excursion toward the STALL AoA?

So I see "G" PROTECTION as a de facto airframe limiter, which not only prevents over load, but allows LOC, and in Losing Control, "G" PROT, having allowed it, prevents recovery "FROM IT".

How can I say that? Because the TRIM started to LOAD the airframe, in STALL, when to unload it, or allow it to be unloaded, would facilitate recovery.

Nothing Earthshattering about this, it is a point of view. Will you attempt to see it that way for purpose of understanding?

Climbing UP, PF had an airframe that appeared NORMAL, but was rotating to absurd PITCH UP. By that I mean, his climb was incremental, and indicated no disaster in the offing. (possibly).

If PILOT/PLANE communication is critical, wouldn't the a/c have annunciated to the crew[/I] that pilot input was being g managed?

In a perfect world, one then says "but he should have known this", no denying. Was there an clear alert that instructed the manual pilot that basic, and life protecting systems were operating the Plane, and not he?

I have a sinking feeling that the PF was possibly unaware "g" was molding his inputs to an incremental PITCH UP that he may have sussed was not potentially very hazardous. Otherwise, why the gruff Stick demands?

add. "Attitude" and 'g' PROT are not related. There can be (have been) circumstances where 'g' PROT might have wanted to be sent packing?

The chronic application of PITCH UP by this pilot is made easier to understand (by me), when one imagines the environment, the lack of "Response", and the inappropriate nature of some of the cueing.

THS. There is a command in medicine, that applies to the inappropriate automatic application of TRIM:

"First, do no harm"...... perhaps engineers should have a short 101 in patience at onset of disaster, as well as Physicians.

Only THS made NU effective?
 

I think that this may miss the point.

If (as suggested earlier) the THS had remained at NEUTRAL rather than chasing the NU input during a stall, would the PF NU inputs have been enough with elevator alone to maintain nose up into a deep stall? Was it only the added authority of the THS that allowed the aircraft to be kept in the stall?

Perhaps with elevators alone and a THS neutral the aircraft would have dropped its nose, then (had PF kept NU) after getting flying speed its nose would come back up. Perhaps PF was expecting this nose drop 'nodding' behavior? Its what would happen in a lot of gliders and light aircraft and he was glider qualified. The lack of this nose drop possibly convinced PF that the aircraft could not be in a stall.

Was there any training or flight envelope information available to A330 crews that told of the possibility of deep stall? There seems to have been quite a lot on 'spurious' stall warnings.

So without any knowledge of deep stall, with THS having sufficient authority to hold the aircraft in a stable deep stall so no nodding ND, and previous information about spurious stall warnings: everything seems to be set up for a confused PF. :confused:

Lyman,

Let's go step by step:
- I do agree that the autotrim going full UP is a bad idea. Re-read my previous posts (discussion with airtren) on the subject.
- I do agree that AoA/stall (hard) protection and pitch (hard) protection were lost on AF447. That's the very raison d'être of the Alternate Law: when the plane can no more grant full protection, it reverts to Alternate (or Direct, if failures are more than what allows Alternate to be invoked).

You're saying - unless I'm mistaken - that "g demand" flight controls are dangerous and "unknown" of the pilot?? May I remind you that the Normal Law is also g demand? May I remind you that, apart from Dassault's Falcons, all FBW civilian aircraft use the g demand philosophy? There is no need of being in a perfect world for hoping that pilots know that!! :confused:

Yes there was. ALT LAW (PROT LOST) on the ECAM means just that. And this was acknowledged by the crew (see CVR transcript).
On a side note, I wouldn't call the g protection (nor the whole g demand law) "life protecting systems". They're:
- structural protecting systems for the g protection
- standart way of flying the aircraft for the g demand law.
Nor the g protection, nor the g demand controls alone will prevent any pilot to do what he wants with his plane (even stalling it, or recovering it from stall).
It will only - if needed - prevent him to do it too fast for the aircraft structure to cope with. The aircraft will retain its wings. Good idea, isn't it? :ok:

On the whole, I don't get it. What are you trying to prove? That a pilot must know its plane? I took that for granted... ;)
I do agree that a PPL being thrown in AF447's cockpit could have difficulties with the g demand law. But we're talking of a professional crew, here, with ATPL & type rating licences. :ugh:

Can't we put this deep stall nonsense to rest already (along with coffin's corner)?

The "inputs" PF (and crew) received
 

Hi,

dufc,

The "information" (we don't have it) PF received (when a/c was operating outside* it's design) led him to an "strange behavior". We need more info to understand PF persistent NU.

When 3 qualified pilots fail, even to "understand timely", probably we have something very serious in the a/c (design, cert, training, operation, etc). The very basic info MUST be absolutely reliable and presented in real time by the a/c resources to the crew. Complex machines may fail in this aspect. And should not...


(*) F-GZCP at that night, operated "outside design":

1) Facing WX (icing)
2) Too high (briefly)
3) Stalled

Vielen Dank, Franzl, for posting "Pilot guide to aeroplane upset recovery". It is very useful reading, learning lessons from it might save someone's flying rear yet but I do not think it is applicable to AF447 case. It mentions that definition of aeroplane upset includes unintentional. Beyond any doubt, pulling the aeroplane into stall was not intentional, however aeroplane did just what she was commanded to. Looks as if 447's crew simply forgot how to fly an aeroplane. So crashed.

My sincerest apologies, sir. I was under distinct impression I was debating with professional pilot, rated on FBW Airbus. I mistakenly believed that we share some common background so there would be no need for me to go into details that are ingrained in basics of airline pilots training, such as technique of instrument flying. I now see that by omitting the details I believed would be familiar to you, my answers came across as quite harsh, snobbish and disrespectful. It was not my intention. From now on I'll try to dumb it down to level of high school physics.

Most important and most often checked information in "blind flying" is attitude. If one cannot read it properly or cannot maintain it properly, the rest of instrument scan is in vain.

When pilot is handflying by sole reference to instruments, it is important to keep movement smooth and precise to avoid unnecessary maneuvering that might upset pilot's sense of balance and induce illusions of turning or banking. Pilots who, when without outside visual reference, start flying by their senses instead by their instruments, get far more often killed than not. That is known fact that is with us since there were first instrument flights and no amount of sophistication and automation is able to isolate us from it, as was correctly, in more general terms, predicted by Antoine de Saint-Exupery.

So, as instrument rated pilot, I don't fly by feeling Gs, I fly by reference to my instruments.

Non, monsieur. You are mistaking the angle of attack and pitch. Pitch is angular difference between aeroplane's longitudinal axis and horizon. Angle of attack. in the most layman's terms, is angular difference between where nose of the aeroplane is pointing and where aeroplane is travelling to through air (velocity vector), measured in aeroplane's vertical plane. So AF447 was traveling at 2.5° cruise AoA and recieved first two stall warning as it was pitching up in turbulence, they were quite short and only transient and stopped promptly. It is also important to understand that stall warning sounds before actual stall takes place. It is certification requirement, purpose of which is for pilots to have enough time to make corrective actions before actual stall takes place.

Old unreliable airspeed procedure directed pilots to fly 2.5° attitude and power from table. New procedure, valid at time of AF447 final dive, called for setting 5° pitch with climb power for a couple of seconds, while PNF takes out the table of pitch-against-power from QRH and then power and attitude are set accordingly. 2.5° pitch is fine if you know your cruise power by heart. With climb power it would likely result in overspeed.

I would expect them to do exactly that as UAS procedure valid at the time of crash demands it. Page 59 of accident report refers. Your gut feeling is correct, I have explained why a few pages ago.

Demanded load factor was met by elevators alone. Reason? High dynamic pressure at start of the climb.

They maintain attitude when stick is pitch neutral. In normal and altn law they are programmed to meet G demand set by sidestick.

One only needs to look int Flight Crew Operation Manual (FCOM) to see that info. Pilot input is always G managed, except in direct law.

Only if one is purposefully set on breaking up the aeroplane in midair through overstress. Absolutely not applicable to AF447. Aeroplane never came close to G limits.


People who don't understand that if they pull and nose doesn't come up (EDIT: sorry, I wrote that terribly wrong the first time), there are 99.99% chances they are stalled, are usually not allowed to go solo in gliders, microlights or light aeroplanes, let alone climb the ladder to professional aviation. 0.01% caters for airframe failures, control circuit failures, etc.

There is absolutely no NEUTRAL position as such on any THS fitted to any aeroplane, anywhere. There is neutral position for speed, altitude, weight, balance and configuration. It can be anywhere within stabilizer operating range.

No. It would be a lie. Airbus 330 is not prone to deep stall/ superstall/ locked-in condition.

Stop moaning about that, Zorin.....
It's a matter of terminology, further confused by the early "locked-in stall" accidents of some of the early T-tails being referred to as "deep stalls".

I would have called AF447 a "deep stall" in the general sense, in that it was a persistent, fully developped stall, with a few nasty contributing factors (no airspeed, THS, confused meatware), which lasted until FL000....

Maybe you could suggest some 'formal' terminology?

AlphaZuluRomeo Thank you so much for your response.

First, whether 'g' or mechanical, (RTLU or 'g' airframe) we speak of a direct and powerful LIMIT. The type of limiting is not relevant, suffice to say, the limit exists to prevent airframe damage.

ALPHA PROT is a FLIGHT PATH Protection. 'g' limit is an airframe protection.

From a design point of view, some things of note: Any Limit is considered as a boundary, not subject to mitigation, it is on, or it is off. It is not a function, nor is it a method, of Flight Path control.

So no one has addressed my opinion that the climb up was a function of "g" inhibition of the THS. I hear that "Control (stick) was not sustained", "thus the THS remained unmoving." This same argument is used on the descent, "All he had to do....." etc.

My Point? 'g' limiting was the source of the shape of the climb curve, along with the PF input at the stick.

It was the PNF who SAID: "SO, WE HAVE LOST THE SPEEDS.........ALTERNATE LAW".

WHY? Because I think PF was flying thinking he was in NORMAL LAW, NOT ALTERNATE LAW, hence the REMINDER.

With 'g' values wandering above and also below thresholds for THS TRIM,
'g' was flying the Aircraft; the PF was inputting stick, and the results were derived from 'g', via the Computer FCS. NO THS TRIM, it is inhibited in this window(s). An increase in AoA allowed by 'g' sensing, not the Pilot.

This is mode confusion. Call the Pilot flying whatever you will, IF he thought he had one Law, and didn't (couldn't) relate it to basic control, it does not matter whether he was Yeager, Yogi, or YODA, the a/c was not sussable. "THE AIRCRAFT DID WHAT IS WAS DIRECTED TO DO."

My point, simply...SIMPLY is this.

This is a FLAW. All Pilot derived? I DON"T CARE. The a/c got to be a mystery, and it was lost.

There is not one pilot here who can honestly say he could have done better. PERIOD. And it does not matter for purpose of this discussion, imo.

ICE is not PROVEN. IT IS NOT EVEN A CONCLUSION SUBJECT TO, PROOF.

PITOTS failure is not PROVEN.

1. The aircraft STALLED

2. The aircraft did not recover.

At the STALL, the THS was full UP.

My proposition is this. All three pilots could have been TIRE, TIRE, TIRE! from the outset. Because the THS was FULL UP, the NOSE COULD NOT BE LOWERED.

IF THE THS had been neutral, the pilots could have pulled TIRE TIRE TIRE!
and the a/c would have recovered in spite of the wrong input. Had they continued their pull, it would have STALLED AGAIN.

Do you see? The a/c prevented a recovery.

NOW. How did it cause LOC? Because the Pilot got incremental nibbles of NOSE UP, as it would have in NORMAL LAW. And it STALLED at nil AS.

Discard 'g' protection (for the moment). The Pilot gets a BUNCH of NU elevator, and the a/c Stalls, immediately. The nose drops, he recovers (hopefully), and all is well.

Do you see this? I am not judgiing, moralizing, or defending. I am saying that for whatever the reason, the DIRECT cause of this disaster is the aircraft itself.

If you can patiently entertain that pov, let's discuss. Too many PPL's here stroking themselves on the graves of professional pilots, methinks (ok, that is a judgment).

Clandestino, either for reasons of ignorance or conceit, you continue to "misunderstand" or dismiss with great prejudice the posting of others. Anyone who snubs someone who has engaged you, with a picture of a book and a "read this" is too arrogant to waste my time in response.

btw. In the descent, the STALL WARN returns, and the PF is accused of NU. Several times. Why would the STALL WARNING trigger? And what effect would this have on 'g' Prot?

I'll wait, whoever sees where I'm going will likely be better at explaining why the PF "PULLED UP".............

Franzl,
A very pertinent series of points.
I suspect the "unload" term may be strange to those who have never flown tactical aircraft. It literally means to take the load off of the wings (which puts you into a ballistic trajectory).
It is usually not absolutely necessary to perfectly hit zero g to unload.
One tenth of a g keeps things planted on the floor and is thus a safer thing to do when carrying passengers.
Example:
If your aircraft has a 180 knot clean stall speed at 1 g, then your stall speed at .1 g will drop to 57 knots. Very useful for maintaining control of the wing attitude (even though you are on a ballistic trajectory).

Airtren's comments re the Interflug A310 Incident, near Moscow, in 1991
allowed me to find the following youtube posting which makes a whole range of relevant points among which I find the comments regarding the problems with keeping the pilots in the loop while the computers fly the aircraft to be particularly relevant to AF447.
Blackbox - 05 - Blaming the Pilot - Part 5 of 5 - YouTube

Parts of posts that are at odds with the facts, I dismiss with extreme prejudice.

In the air you live and die by the facts, not opinions.

That's what "Handling the big jets" is about.

It's one of those great books written in blood of those who have never put their final flights down in their logbooks.

Yes, and I appreciate your patience, I left you an opening, and you resisted. Thanks, I'll go rest.

Real time relevant information to the crew
 

Hi,

GerardC :ok:

I posted earlier on that. And considering the a/c was starting to operate "outside design" (sub heated pitot's) the information of what caused AP/AT out SHOULD BE PRESENTED IMMEDIATELY. Actually the a/c was designed considering a near zero probability of SIMULTANEOUS pitot "failure". And the a/c entered an atmospheric region that caused a (near) simultaneous "failure". And the pitot's (certainly) not failed. Just was operating outside the specs.

IMO the operation of an a/c outside it's design and the fact this info was not (still currently) presented IN REAL TIME to the crew is almost an ABSURD. That may allow you transit from "Normal Law directly to Murphy Law"...

Ian_W

Transcription de la conférence de presse du 29 juillet 2011

Some answers from Troadec (BEA director)

.


Let me add to that, it is not only refence to the flight instruments, but also to the performance instruments .

It ís in the former mentioned reference upset recovery training at the beginning.

Flying is mainly energy management. With autopilot and autothrust combined with low drag aircraft and strong engines it seems to be a forgotten fact.

It is not understandable to change altitude (intentional or unintentional) without attention to powersetting, speed change and vvi change. Change attitude, change power, except you want to accelerate in diving or decelerate in climbing. No need to wait what the speed will be doing, because that can bring one already behind the aircraft.

Machinbird :ok:

And during extreme situations this can be simply vital.

That feeling of g
 

But we do fly with input from our posteriors for the feeling of g.
It isn't a normally a primary input for control of the aircraft, and our internal sense of vertical should be only aircraft referenced (that is, it should not be referenced to the outside world attitude).
That little tactile sensation can feed us a lot of information regarding rate of g onset, level of g achieved, and whether or not the rudder is trimmed properly. It is just when we try to infer up and down relative to the earth that we get in trouble by trying to use it.

Dick Rutan recently gave a very interesting briefing regarding his round the world trip in the Voyager aircraft. At high gross weight, the aircraft had a divergent "pogo" type oscillation that required constant pilot intervention to control. He was controlling the oscillation by visual reference to the wing tips, and it occurred to him, "How am I going to control this thing at night when I can't see the wing tips?" Part of his test flying was to prove that he could control the oscillation by seat of the pants. They covered up the windows with quick remove panels and adequate control was maintained-by "seat of the pants" flying. The rest is history.

The 'deep stall' theory came up because it seemed much more plausible that a professional crew couldn't get out of a stall rather than wouldn't even try to. Especially the media picked it up readily, because it sounds appropriately dangerous.
Now many use it as a synonym for "really bad stall", which unnecessarily confuses people. See Ian's question, "were they told of the possibility of deep stall?"
Uhm, no, it wasn't in the "locked-in" kind and yes, it's got wings so obviously it can stall...
It's a garden-variety stall, do we need a special name for it?

Stall without THS NU
 

Originally posted by Ian W
Response from JCJeant
Thank you for this response. My query took this just a little further. Had the THS been at a more normal cruise setting and not fully NU, would the PF been able to hold the nose up during the established stall - with the aircraft dropping at 11,000 fpm (over 100 kts vertical component) - using elevators alone? Or, would the aircraft nose have dropped despite the NU elevators? Surely someone must have calculated this?

I wouldn't write this off just yet. There's been a former F-16 driver and some others here describing some pitch moment considerations that may merit some further attention.

OK, OK....

Why are you waiting? It certainly was not a garden variety STALL. Point of fact, it wasn't technically, a STALL, at ALL.

With powerful engines, clean design, and sufficient DRAG, this a/c was essentially performing a "maneuver".

Bouilliard refused to answer the jouno's questions. For once :D to the nice lady asking the question, the 64 dollar question. "Why was there no "Recognition of STALL, Monsieur?"."

"Well, that is a proposition for the working group, Madame."


What a PILOT believes, is reality. By extension, it becomes the reality of all aboard.

"As long as I keep the Nose UP, she won't STALL."

In these (447) conditions, he is right, 100%. Not once did the airframe experience the only true symptom of actual STALL that he could have related to. NOSE Plummet. lose your lunch, point at the deck NOSE drop.

At any time down to 4000 feet, I believe she could have recovered, and easily. Why couldn't (didn't) she? The THS prevented it. Also the a/c "Protections". And the belief that the pilots held, at the end, "Tire Tire, TIRE!"

Her forward speed, perhaps all of it, plus a good deal of ballistic energy keeping her aloft (by 'reducing' her RoD) came from the engines. She was airworthy, had a serviceable assiete, good power, and a willing crew.

1. gums knows. Machinbird knows. Smilin Ed knows, and Monsieur Bouilliard knows.

2. We will all know, but it will take time.

The pilots went to Heaven believing she was not STALLED, and that was the reality for all aboard. In fact, again, technically, she was NOT.



The indicated recovery for this "Maneuver"? gently lower the nose, build forward speed, and call for coffee. No "reloading" the wings, No dive, no plummet, no nothing. This may be the first a/c that convinced everyone she Stalled, and did not recover, when instead, she was doing a bit of air combat maneuvering.

OK?

Hi,

Ian W
Certainly not the BEA.
Jean-Paul Troadec answer is very clear:

The airplane is certified and meet the certifications requirements .. so .. the plane is so far "perfect" and so .. no modifications (on the THS automatism or behavior) are required (so far ..................... )

And here I was, thinking your gibberish couldn't make any less sense... Boy was I wrong.

On failures
 

3holelover,

IMO Airbus SAS failed: There are some ways to present to the crew an imediate understanding and even ways to keep a/c in Normal Law after UAS (an old and well understood problem due sub heated pitot's). The plane certainly worked as designed wrt to AS. The design could be improved, was not (wrt to UAS) and eventually Murphy Law put all elements together at that night.

IMO the first slice ("swiss cheese") was this Airbus SAS failure. A latent failure. Their a/c are designed to operate for random (time) failure of Pitot tubes and NOT simultaneous (brief) erratic data coming from the redundant sensors. This certainly was consider highly improbable in the design. But the 30+ UAS cases before AF447 should have alerted to a rethinking of the design from the designer/manufacturer. A simple one as we could imagine.

And the patent filing (of an AS laser device, posted earlier) from Airbus SAS was made months AFTER F-GZCP loss.

The importance of AS is considered so high, there are THREE redundant elements supplying this info to the a/c.

IMO just to rely on Pitot's replacement (to another model also prone to "fail"), and operators crew training was insufficient for the company that introduced FBW (and a/c new control philosophy) in commercial aviation.

Zorin75
Hi Zorin. When you get well away from the initial point of stall, new things come into play. CL now depends on Aspect ratio, thickness ratio and Reynolds number in addition to Alpha. Remember this reference we discussed a few months ago? http://wind.nrel.gov/designcodes/pap...44XX_Part2.pdf
Pitching moment can change. CD continues its increase fairly smoothly. It isn't the same old stall you experienced when you nibbled on the edges of it in training.
I think the deep stall description is warranted. Sixty-one degrees final AOA was closer to Broadside to the wind than to flying.

Is M. J-P.Troder (B.E.A.) comparing training aircraft and gliders, which would normally pitch nose down when they stall, usually with any power off, with an large aircraft (A330) with underslung engines operating at TOGA ?

I assume that Approach to Stall training is not done with high thrust, but I do not know.

Same reply : Attitude is the objective, but 36 ways to reach that goal, how smooth or not you can or want to be is the director of your inputs.

flying by own senses is known as not believing the instruments, this is another matter.

Understand you're pretty close to perfection when flying instruments, never get tired never misjudge your inputs in order to proceed to an attitude change, so never need to adjust the initial input to get things smoother as they are already.
I am impressed I must say, you desserve my hat off really.

But are not you the one to teach your FOs how 5 degrees of pitch magically equal 5 degrees of AoA when unable to reach higher ?

"A couple of seconds" ... Once again I am impressed how efficient you are.
On my side, to be honnest, it would probably take me a couple of minutes at night in turbulence and my level of stress ... From 350 I figure soon enough I'll reach 4 and 5 degrees of AoA and that bloody stall warning.

As 99% of my cruise flight time N1 are between noon and 1 o'clock, I figure again that could be a reasonable match to the 2.5 degrees attitude.

You mention the "old UAS procedure". I'm not aware of it, neither the BEA ... Would you forward me a copy - Do you know the reason for the change ?

"harsh, snobbish and disrespectful" ?
No, what make you think so, actually it must be a delight flying with such the Professional you are - Some are luckier than others - I do appreciate your patience too - BTW I still expect to graduate next year ...



Do we have their source ?

Zorin, bear with me.

447 is descending rapidly with a reasonable attitude, if you dislike reasonable, call it consistent, dependable even. Her airspeed is divided about equally into horizontal and vertical components. I don't know if you have flown this, but it is not a freak show. She had power, directional stability, and active elevators. She literally could have slowly recovered cruise flight. The idea would be to arrest the descent, increase forward speed, and get the Nose into the airstream, not in bias to it.

Slowly. When the PF dropped the NOSE, and heard the STALL WARNING, he was averting disaster by pulling UP, not inviting further problems.

Machinbird has just explained it to you. Had I the gift and the experience he has, I could do it. You want to see the Shiite, and won't open your mind even a feeble little crack.

If PF had continued lowering the nose through STALL, and kept it there, the a/c would have been lost immediately.

I think the PF learned alot from the moment he wiped the sleep out his eyes and took command. He didn't quite get that staying on the upside of the horn was the thing to do, just not so much. That STALL WARNING was real, accurate, and told him the truth.

You want someone to say that this "STALL" merely wanted a conventional recovery, and anyone who can't give one is bogus. Listen to Machinbird, or gums, or especially OK465. There are times when a/c don't fly the way they're 'posed to. And won't. If these gents had gone to school with gums, or Mach, they would have recovered the final descent, easies.

But then they wouldn't have had the initial screw up, either.

This is not gibberish. Alas it isn't in the place you want it. You want nuthin' from me, so listen in other places.

all the best, the solution is at hand.

"deep" stall versus "deep stall" again
 

Salute!

I tend to agree with the term "deep" stall versus the other.

Aparently, in the commercial jet community, the term "deep stall" gained popularity with the T-tail design. However, even a "conventional" horizontal stabilizer design can wind up in a very stable stalled condition, as we proved back in 1978 and 79 in that little jet I flew then.

It all depends upon the jet's pitch moment at certain angles of attack. And remember that your pitch moment is affected to a great degree by the THS or HS or whatever you want to call it.

So it is entirely possible that Airbus modeling/wind tunnel runs will find that with a sufficiently rear center of gravity and the THS at the maximum deflection then there is insufficient nose down authority with the elevators.

I DON'T THINK THIS WAS THE CASE WITH AF447

We see glimpses of nose down attitude changes and reduced AoA, then we see continued nose up pitch attitude and continued nose up commands by the pilot.

No doubt in this Viper "has-been" 's mind that the fully deflected THS made the situation tough, but I can't convince myself that recovery was not possible, especially if the stick had been held forward long enough for the "laws" to move the THS to follow the pilot's command.

Lastly, at sufficiently high AoA, the ailerons will cause the nose to move opposite what one would expect and not have a big effect upon actual roll attitude. Ask 'bird, RF4 and Smilin' Ed.

Hi,

CONF iture
http://i.imgur.com/fIgpd.jpg

If you are not confident (I'm) with the Alter statements in their note of 19/08/2011 .. you can contact them for more details:
ALTER - Accueil

Despite what others have said, the dudes that pulled this thing into a full stall and held it there for almost a full minute should have known what was happening but then when they pushed the SS down and the stall warning sounded again they pulled up again proves they had no clue what they were doing. Automation at it's best is now showing how pilots should really be pilots. Not systems operators.

This confuses me because lowering the nose was the only recovery. If done soon enough it would have saved the day. I think this guy is smoking something.

Lyman
I have???
Lyman
Lyman (Bearfoil), you are lost in space I'm afraid.
Angle of attack needed to be reduced to flyable. It wasn't. There is no stress that would be applied on the aircraft beyond its design intent by lowering the nose to a good 30 degrees nose down or more to restore flyable angle of attack. To do so required running the trim back down. That was not done with either autotrim or manual trim. Once flyable angle of attack was restored, the remaining problem would have been to pull out smoothly before hitting the surface. Then the emergency would have been largely over.
I have noticed a pattern of attention getting behavior on your part. In a forum such as this, it is annoying. There are serious matters to discuss. To have the discussion pulled this way and that by such childlike behavior interferes with proper communication. :=
If you are having issues with remaining relevant to society, or if you seek the company of other aviators perhaps you should look at other venues.
In the future, please do not attribute thoughts or ideas to me that I have not originated or do not hold. I do not agree with the ideas of your prior post.:*

Possible, but we'll never know...

The re-trimming to maintain G as speed bled off due to aft-stick, seems to have played a good part in disguising the true state... one glance at that trim-wheel at that altitude would not have computed

Hi jcjeant,
Your post #271 carries a stunning claim.
It alleges that a test flight at the AF CEV (the AF test flight center) to replicate the AF447 conditions found the aircraft fell locked into a deep stall that the test pilots were able to recover from only by cutting the engines. I tried to get to the full report by following the 'ALTER' link you left, but it appears limited to people with an Air France background.
Is there any possible confirmation of this and do any of the aerodynamic experts here believe this is even plausible?

Etudiant, I think you read the Alter site correctly. It is asking for a ID number and password.
Even with the AF447 "test flight" paving the way, I would be surprised that anyone would take the risk of a test flight to study deep stall behavior of the A330. I did personally theorize that AF447 must have created a lot of valuable pitching moment data on its way down.

I do not claim to be an aerodynamic expert or a test pilot, however the low slung engines found on most modern transport aircraft would create an adverse pitching moment that would make stall recovery difficult, so pulling engines to idle to recover is not an unexpected maneuver. Once the stall is broken, then power could be advanced.

If they have actually performed a deep stall test, then I would expect information regarding the results to appear in the BEA final report.

Hi machinbird,
It is also claimed in the ALTER writeup that the AF447 pilots were following the prescribed recovery procedure. The language used indicates an actual flight test was performed.
My only reservation is that the document reads more like a polemic than a sober aviation document, touching on everything from the kickbacks paid on French arms sales in Pakistan to the Habsheim crash. In that event, it notes the pilot had not been made aware that the engines on this aircraft had a much longer response time than what he had been accustomed to. This seems a stretch to me, afaik both the IAE as well as the CFM engines on the A320 take several seconds to spool up, but there may be a difference. If anyone knows the specifics, it would be a simple credibility test.

rudderrat, as I read your "upset / stall / recovery" posting I mused a little about the state of mind of the pf. He's above a heck of a storm that was big enough to reach out and "touch" the airplane and cause airspeed indications to fail. After he overreacted and zoom climbed 1500' he found himself in stall warning conditions. He overdid the increase thrust part and under-did the ND part.

I got to wondering if he was deathly afraid of descending into the storm even if it was required for stall recovery. He'd not have to descend all that much to gain back most of his lost airspeed if he reacted sensibly and rapidly. Could the fear of the storm been bouncing around in his head biasing his thinking away from the intuitively insane* ND action?

I can't help thinking, "I really really don't want to go down into that storm," was bouncing around in that poor fellow's head. So, ironically, he descended all the way down through that storm he might have been trying with all his might and soul to avoid.

* Only experienced pilots would recover from "falling" by trying to fall faster. They've been trained that this is the way you get the required airspeed over the wings to give you lift. For real stick and rudder pilots and even military FBW pilots who have hours upon hours of active joysticking behind them this becomes the intuitive response as insane as it seems to a lay person.