Yes absolutely. But if any part of the wing stalls it still has the effect of moving the centre of lift forward purely because of the separation of the airflow from the rear of the wing section.

My 'entire wing' thing was just an example of that.

A deep stall can be induced on any aircraft with enough elevator authority or as a result of design. Recovery from a deep stall can be harder to achieve if the elevator then becomes less effective as per T-Tail aircraft or some other configuration.

Considering that AF447 AoA was somewhere between 35 and 60 degrees you can surmise that the horizontal stabiliser also had a similar AoA, effectively the HS was also stalled. If they had made a large nose down input to attempt recovery that would have the effect of increasing the AoA of the HS past 60 degrees. Coupled with TOGA power I suspect the effect of the ND input would have been negligible.

In that case, pull one throttle to idle, give it a handful of aileron and a boot of rudder to get it into an incipient spin, then recover to flying speed with full forward stick.

:eek:

The "then recover to flying speed..." part, though sounding good, appears to have at least the potential to be a bit problematical.

Got any better ideas?

You are all ignoring the nose down pitch change that occurred each time nose down elevator was applied?

BOAC indeed +1

Was there a significant trend of AOA reduction with the pitch changes?

Have you actually looked at the FDR trace? Tell me what you think.

Nose drop with back stick is a classic stall indication taught at the PPL stage.

I don't think Flap 1 is used for stall recovery. It is, I believe, in the QRH POST stall recovery. However, if nothing else is working, most pilots would (I hope) try lots of things including gear down.

Note that even during the two attempts at ND inputs the elevators only reduced from 30 deg to 15 deg up, they never even got to down elevator...

Very true, and as AZR stated, we don't 'ACTUALLY' know the effect of a positive ND SS input, because they never got there.

It is one possibility that a stall recovery could have been achieved, but not a certainty. I would prefer to see the final report rather than make assumptions, regardless of how well founded they seem to be from experience with previous or other aircraft flown.

Clandestno.....fantastic post: True, what also doesn't sit well is the fact that the plane just fell out of the sky in a stall. The tail didn't tear off, the engines didn't fail, there was no "act of God"...

I have been reading the AF447 threads since day one and have absorbed every conceivable scenario pointing towards some sort of aircraft malfunction. This obviously would have been an easier way for people to digest and understand what had happened.

But from what we know so far...it seems two qualified pilots became disorientated, didn't correctly address the situation, and foundered without fully understanding they were in a stall....

That is hard to deal with, and adds to the depth of the dilemma of trying to comprehend this disaster.

This is everybody's nightmare: pilots, passengers, manufacturers, airline companies....and it isn't going away...

It's only a nightmare for me because some expert has told me I can no longer practice what probably would have saved their lives: flying the aeroplane. I don't care what it is: a gentle turn here and there, a raw data ILS on a gin-clear day with no traffic, it all helps me to get in tune with the machine and hopefully, when things to go completely haywire, I'll have the skill to assess and react correctly. An auto-trim design doesn't help, of course.

Don't get me wrong; I am not suggesting spin it, just "upset" the upset to break the status quo. Incipient is the word I used. :ok:

Yet again we are seeing a thread that is out-performing the Oozlum bird.

Here we are, over two years of time to digest, argue, prove that (supposedly) type-qualified pilots don't understand it, look at FDR traces, see CVR transcripts - and we still don't really understand what happened.

We have two fairly inexperienced lads, and an experienced Captain, who presumably have been told that this a/c will protect you from cradle to grave (!!) and cannot be stalled and that one 'OK' thing to do when in difficulty is to put on full power and pull back the Sidestick - and she will sort it out. 'She' didn't. To make matters worse, when they relax the back pressure, it tells them it is stalling again. Is it any wonder they were confused?

What is apparent is that auto-trim contributed to this accident as it also did in PGF when it trimmed in manual flight and the 737 at SPL. when it trimmed in A/P.

If, apart from training issues, nothing else comes out of this I would hope that as I said after each of these three crashes - there HAS to be a point at which the trim system stops at some pre-determined value and ASKS for confirmation that what it is doing is what is wanted, particularly in the AB types and the newer Boeings where trim operation is 'un-noticed' - 'silent - but deadly'?

Doesn't auto trim stop when you go below Vls? The worry for me isn't that they couldn't get out of the stall but that they got it there in the first place!

Oozlum Bird. Good one BOAC. :D

Of course it does! It reminds of my snide remark that mental gymnastics some posters apply are awesome to behold while being of poor to nil informational value.

I don't mind stressing for the third time: we're discussing the deep stall as related to transport category aeroplanes and as is described by DP Davies, certainly an authority in the field of transport aeroplanes behaviour. Reference is "Handling the big jets", pages 115-119 in the third edition.

Velocity is four seater aeroplane. A330 is not.

Velocity is piston powered aeroplane. A330 is not

Velocity is single engine pusher aeroplane. A330 is not

Velocity is canard aeroplane. A330 is not.

There are also some differences between Velocity and A330 regarding the mass and wing loading.

To just wink-wink-nudge-nudge-you-know-what-I-mean in order to somehow make an impression that something that Velocity's test pilot has encountered during test flight and was labeled by NTSB as deep stall has anything to do with transport aeroplane's deep stall and therefore further imply that Velocity incident somehow proves that A330 is susceptible to the phenomenon is beyond my ability to comprehend. Why would anyone mix handful of facts with bag of suspect notions and expect to get something meaningful out of it is enigma to me.

If we'd call every extremely high AoA situation deep stall, there would be no end of it.

Why? Because you would have to kill me if I see it? Can't you at least hint what aeroplane is dealt with in your papers or someone would get you if you release that little bit of information?

References contrary to your claim can be found in "Handling the big jets". third edition, page 119. Or any decent basic aerodynamics textbook, e.g. Atlantic Flight Training ltd JAA ATPL training handbook, Principles of flight, pages 8-14 to 8-16 in 2006. edition. Those were first that I dug out of my bookshelf and I can't publish excerpts due to copyright issues but if you really want to know what's written in them, i don't think you'll have problem finding out.

You were on good way to tautology before you slipped into something akin to surrealism. Of course that recovery is the problem! The biggest part of the deep stall definition: it's irrecoverable!

But it doesn't follow that moving the Cp in stall forward results in pitch-up! If it were so in the real world, we would be in deep trouble and I certainly would not be writing this post but pushing daisies at certain quiet village graveyard.

These roll excursions started when aeroplane was extremely deeply stalled. Whether they were stopped by CM2's monstrous effort on the stick or by sheer incident is something for aerodynamicsists to resolve. Aeroplane has stalled somewhere around 02:11:06 Z. Next 30 seconds roll is quite gentle, not exceeding 9 degrees. AoA increase is also gradual and that is somewhat at odds with the theory of tips stalling first.

As for 270° turn, I find it quite astonishing for diametrically oposite reason to you: that it was so mild. 270° over three minutes gives astonishing average of 1.5° per second or four minutes to complete single turn. Now I'm only waiting for the next ignoramus in line to state that it was Airbus fault that aeroplane which was never intended to have good post-stall characteristics had so benign stall and if it spun (as B752 at Puerto Plata did) the pilots would have at least an idea what was wrong.

Reason for it might be that I don't recall this information being included in FCOMs, I remember it as part of my training syllabus. When my captain & me went on Airbus 320 TR course, it was for both of us our first MRJT so our company thought it was good idea to put us through something called "Jet transition" It was ten hours of raw data, manual flight in direct law without autothrust for each of us. Direct stick-to-control displacement. Normal pitch-power couplings. Trimming with the wheel all the time. It certainly gave us the feeling what is the aeroplane like to fly without FBW holding your hand. Contrary to horror stories we heard, after ATR it was piece of cake. Near the end of jet transition, ALT law was introduced to give us taste of autotrim and that's when we were demonstrated why it isn't good idea to fight the autotrim - to make sure there's no negative transfer from "Jet transition" into "Normal" phase of training which was conducted in normal law. It didn't come cheap - we have used up 20 hours of sim time and prolonged our course by a week. So did it pay off by making us better A320 pilots than we would be if we just started with full FBW and making just casual acquaintance with direct law during abnormals? It's just my severely biased opinion but I'd say - hell, yes!

Not Necessarily

Narrows, Virginia; ABX Air (Airborne Express) DC-8; December 22, 1996

BOAC writes

Isn't it possible that only happened because of the full up trim? eg it was full up trim that was preventing the THS from stalling.

Had they wound in nose down trim it might initially have caused some nose down pitch but would it have been enough to keep the THS from stalling as the up trim came off?

CLANDY: Thank you for sparing us the pictures this time.

"Sorry. Once again : prior to june 1st 2009 Air France F/Os did NOT get any, on purpose, left-seat flight training.

Some sim sessions ("true" captain not compulsory) just happenned to be with a two F/O crew but the purpose was not to train F/Os in the left seat."



I believe the PF was in the right seat in which case left/right hand orientation should not have been an issue for him.

Oozlum's coming around again........................

Lord give me strength!

There was no b*oody deep stall, man.

The pilot held the stick hard back. THAT is what kept the aeroplane stalled.

Whenever he got tired and released the back-pressure, the poor aeroplane started to recover. Then, he pulled it back again!

Can people read the definition of 'deep stall' or 'super-stall' before using those phrases?

Sorry, Sorry...I went back and edited my post....it must be contagious!:mad:

Sorry, Razoray. My fault - getting frustrated.

BOAC,
Indeed not. Which is why I have been hinting that this was a manually induced and prolonged deep stall.

Clandestino,
You said it yourself. BASIC aerodynamics. ATPL Principles of Flight leaves a lot to be desired. I suggest that you ferret a bit deeper into advanced aerodynamics.

A deep stall is NOT irrecoverable. A deep stall maybe harder to recover in a T-Tail aircraft because of reduced elevator effectiveness. It is the combination of both swept wings AND T-Tail configurations in aircraft such as the 727 that makes a deep stall more of a problem. Elevator/pitch rocking and induced roll are two ways to recover but these may take a lot of time and height.

Swept wing aircraft can all be made to deep stall if you have enough elevator authority.

Of course, pitch up may only be a problem if it's excessive or it's exacerbated by poor handling! I congratulate you. It is possible that the A330 lost elevator effectiveness because of vortex buffeting during the pre stall regime stall which caused excessive pitch up exacerbated by the full NU command led to deep stall entry.

Aileron Drag,

There was no bloody locked in deep stall.

If adequate control authority is not available to recover you are in a deep stall. Usually because of vortex buffeting on T-Tails or, on other types, anything else that reduces elevator control margins.

Lord Spandex Masher

I was taught aerodynamics here - on Planet Earth.

I really am not sure where you were taught.

This is in English......................

There.....was......no......DEEP.......stall.....in.....this. ...case.

Lord Spandex Masher, I urge you to take your own advice.

Oh YES IT IS, mate; and I have one dead friend to prove it.

This is utter garbage.

That's what I've been trying to get into your head for days. There WAS NO DEEP STALL.

The PILOT held the aircraft in a stalled condition until it hit the sea.

Let me summarize....

1. AF 447 DID NOT DEEP-STALL.

2. AF 447 was held in a stalled condition by the PF, for reasons known only to him.

Which is presumably why there is no evidence of persistent ND inputs with a voice commentary along the lines of 'I am trying to reduce pitch but the aircraft isn't responding', or did I miss that bit ?

No, Mr Optimistic, you didn't miss that bit.

This guy sat there with the stick held fully back, presumably wondering why the pitch attitude was so high, the airspeed so low, and the RoD so high.

It's so sad. You wish you could have been there, as though in a simulator session, and say to them, "What are you doing? Why are you holding the nose up like this?

"A deep stall is NOT irrecoverable."

You might want to tell the bloke who flew the NASA Schweizer in the deep stall regime over twenty times. That's right, at least twenty entries into and recoveries from deep stalls. Irrecoverable...NO, IT ISN'T.

AF447 was put into and held in a stable deep stall. If they had recognised this fact they may have had enough time to recover. The sad thing is they did not recognise it and held it in a deep stall for over three minutes.

You understand the difference between a deep stall and locked in deep stall?

You in fact have to know what a deep stall is to say that, and I fear you don't.

"I don't really want to be dragged in to the SS/yoke battle except to say that if I had been dragged out of my pit in my silk pyjamas and arrived in a cockpit at 35,000' with 15 degrees nose up, 10,000fpm+ and a co-pilot with the yoke back in his groin, I might have had a clue as to why the nose was up that high - I hope so."

Very interesting point. There has been a lot mentioned about the lack of SS feedback to the pilot but very little about the lack of feedback to the rest of the crew compared to the old fashioned yoke, feedback that in this case may have been vital.

I also wonder about the constant noises bells and whistles going off. There has been a lot of research showing that constant loud noises are an accelerant to panic (as anyone having to deal with a runaway smoke alarm at 2 in the morning can attest) which appears to have been a factor in this accident. By all means aural messages are good but constant repetitive noises will simply dramatically increase stress and degrade performance. The pilots knew there was a problem, and the constant alarms did not help them find a solution.

They stalled.
Failed to recognise their situation and responded incorrectly.

Occam's razor.

No pilots who hold back pressure on the yoke or SS in a stall live very long if they ever stall. I thought it was instinctive to release any back pressure if it ever occured. I know, for some reason they didn't know they were in a stall even with their attitude and descent rate. Strange.

They knew their descent rate, in the end. Originally "I have no Vertical Speed". You think they knew Attitude? Betcha a buck they did not."

The Captain came in...."What are you doing?" "I don't know, but we are descending".

How do we know? Because with an attitude cue, one of these worthies would suggest Nose Down. Occam, again. Slightly less likely is that the two NF pilots were unaware PF was holding back stick, and assumed he was pushing the stick forward. Poor display, poor cockpit design, poor training, poor CRM, shortsighted SW design, inexplicable Autotrim...... all down to Occam? Hardworking fella, this Occam.....

Repeating the same rhetorical "How could three pilots...bla, bla, bla......."
does not suggest, let alone confirm, there was a reliable attitude display.

How many times did PF correct the ship's Nose Down proclivity? Sufficient to climb to Stall? What attitude was he reading? What was the exact source of the disagreement between the PNF/PF re: altitude?

CVR please.......

I wish to ameliorate my previous post by saying that I do not accuse anyone.

However, with the info we all have, one draws certain conclusions, obvious or not.

BEA have replaced what was an unimaginably dynamic cockpit with parsed and misleading bits of data. Drawing conclusions from these is premature. Not even BEA have made conclusions. And they get paid for them.

I know you do not accuse, and that is the sad part, for condemnation prior to investigation is absurd.

That's what gets me.

What would 1g vertical acceleration have felt like in the cockpit during the descent?

That's my conundrum. Certainly one feels it in one's stomach.

It's as though a total lack of instinct prevailed.

As bubbers said, "strange."