JD-EE

Um, no. You missed the key point. The pilot never tried ND input long enough for even the elevator to go past its neutral position. So there never was any real ND input. The elevator moved a little. But it still remained severely NU.

JD-EE

Clandestino, good posting. Regarding, "So, as instrument rated pilot, I don't fly by feeling Gs, I fly by reference to my instruments," I might note that the PF forgot all that and relied, partially, on his feeling of great speed, if I remember the transcript correctly.

Sigh, all this comes back to training bean counters who follow rules and tick off each rule followed as another bean rather than training real pilots to actually fly the plane when the going gets rough.

Zorin_75

Ok, fair enough. I suspect there are quite a few people in Paris and Toulouse right now trying to find out when the door to recovery was slammed shut. Unfortunately we have precious little data about what happens when you try to get the nose down in that condition. It appears that there was some response when they tried, so I'm not entirely convinced they were in a locked-in stall...

JD-EE

jcjeant, why not simply ask Ian W what the plane was doing between 02:11:45 and 02:12:00 if it was not dropping its nose despite the PF pulling full NU?

JD-EE

Ian W, look at the third report pages 107 and 108 (English) between 02:11:45 and 02:12:15. Was the nose down anywhere in there, perhaps with a pitch as low as -10 degrees?

rudderrudderrat

Hi Clandestino,
You are presumably referring to pilots using conventional controls (i.e. Direct Law).

AF 447 crew never felt the nose drop as they approached the stall.
The FBW computers would do their best to maintain attitude (when stick free) by the use of full elevator + stab trim. Any attempt to pitch up more (to satisfy a back stick request) would only fail when they had run out of both elevator and stab trim authority.

Then they may have realised the clues in your initial statement - but sadly they did not recognise that they had stalled.
edit. Their brains seem to have filtered out the "stall stall" heard through their ears (in the same way one can filter out unwanted conversation in a noisy room when trying to chat with someone.)
I believe a vibrator / shaker felt through the hand would grab PF's attention better.

BOAC

I am now a member of the 'Lyman is a fool' club.

- you have NO idea, do you?

- ditto - ditto.

If you have difficulty with the English language, we probably can forgive you. Otherwise please do not waste our time.

AlphaZuluRomeo

Hello

Just quibbling a bit...
A friend of mine, chopper pilot (ex-military), told me of his IMC trainings without ADI/horizon, and how he (and his colleagues) managed to do some nav/airfield -relatively- complex circuits with "just" heading (and its rate of change), airspeed, altitude&V/S and, of course, a chronometer. It was hard, yes, but they just did it.
I do agree, however, that attitude is the #1 parameter, and on everything else about instrument flying you wrote in the quoted post.

/quibble & old memories


@ Lyman:
I'm sorry, I don't understand why you keep saying that the g-demand law was confusing for the pilot or that the pilot somehow "believed" he was in Normal Law.
- Normal Law is a g-demand law too. In other words, there should be no significant difference in handling/aircraft response on the pitch axis ; the differences are the protections, and the fine gain tuning.
- Alternate Law was announced. Yes, it was the PNF who said that. Why? Because it's his job as PNF!
"PROT LOST." If after that the PF still believes he's in Normal Law......
I strongly disagree on the "flaw" you promote regarding the g-demand law. As I'm not sure that everyone here understand what is a g-demand law, let's try to KISS:
Basically, a g-demand flight law is when, for a given position of the stick, the aircraft delivers the same amount of g regardless of the speed, altitude, pressure... etc.

I'm waiting to see how you can write that. Have you made calculations/simulations? Stall recovery technique was never to pull-up. Not on FBW planes. Not on conventionnal planes. Not on gliders.

I see your point. I do agree that a conventionnal aircraft would have performed differently. If the A330 had had the autotrim-up-movement-inhibition-when-stall-warning-is-ON we discussed above, it would also have performed differently (and better).
But I don't agree with your conclusion, which is -if I understood correctly- that g-demand FBW should be discarted. Because if you discart this, you loose far more than you win.
One has to know its tool. And once again: if stalled, push, don't pull. Whatever you're flying, it will always be the correct input (that's, by the way, what the "new" "all-around" procedure by FAA-AESA&Boeing-Airbus says).

AlphaZuluRomeo

May I ask how you would stall voluntary an aircraft, then??

No nose plummet indeed, partly or totally due to the THS position.
But that wasn't the "only true symptom of actual STALL". I'm sure you have heard about buffeting? And read about actual buffeting in AF447, per the DFDR data analysis?

Honestly, it's becoming annoying to have the impression that you select/distord facts in order to fit them in a theory. Apologies if it's not what you're seeking, but that's the impression it gaves (me).
To criticize every possible bit of the aircraft/features, and remove every possible bit of the crew responsability won't help prevent future accidents, you know...


She was not what? Not stalled?
How would you describe it, then?

Lyman

AZR thanks. Besides the NOSE not dropping, you mention Buffet. I think it is quite possible that "What was that" (perPF) may have been an exclamation re: BUFFET, not the STALLSTALL. If it was, PF is shy two major clues as to assiete.

Re: "PULL UP" and recover? The a/c I believe would drop the nose at STALL with full elevator, pending cg accurate point. IOW, in spite of PF's PULL, not as a result of, sorry. With FULLNU THS, she won't.....

The fact remains, there was not a conventional entry, and a non-conventional recovery would have worked. I believe it almost did, save for the THS planted FULLNU. Who is to say, that at 4 degrees AoA, just because the STALL warn returns, there isn't a full on recovery in process?

The secret is to exchange vertical for horizontal velocity, and a dive is not required, (Standard recovery from STALL). A dive makes things impossible.
"Fly Through with POWER"....AIRBUS)

Power would have overcome the descent, soon, and without a 20k loss in altitude. So instead of FULLUP, if the PF had maintained back stick at that 4 AoA, (but wait, HOW does he KNOW what stick to keep? ) allowed the engines to power the a/c "through" the ballistic portion of the event, (IT'S in the BOOK), recovery is attained. And, in the traces the PF is shown to be applying his training re: STALLSTALL, and it is "working"; he pulls too hard instead of maintaining only, AND the THS keeps the a/c from recovering.

Apologies for the disjointed writing, had strokes last year.

Oh, and "NOT STALLED". I left out the pinc , majrks, Of course, a Stall, but "What a pilot believes is reality," not STALL/ sorry

In a broad sense, one can say that this airframe flew like a little jewel for these pilots. Better than a little fighter, even.

What did her in I think is the engineers who harpooned her in the ass with that THS.

AlphaZuluRomeo

Hi etudiant
About Alter's last BSPN, there is a more simple "credibility test" one can do:
Alter writes that the events (loss of speeds & other associated alarms) "conduit les pilotes à perdre le contrôle de l'appareil (alors même qu'ils effectuaient scrupuleusement la seule procédure que le constructeur leur imposait de faire en pareil cas)"
[my translation] the events "led the pilots to lose control of the aircraft (even though they were following scrupulously the only procedure that the manufacturer required them to do in such cases)"
=> Really? Let's remind that this very procedure called for (memory items):
- announcement "IAS douteuse" (Unreliable Air Speed) by the Cpt
- AP, A/THR & FD OFF
- 5° pitch up
- AND CLB power
=> wheras AF447's crew:
- didn't make the announcement nor called for the associated procedure (QRH)
- didn't select FDs OFF (AP & A/THR were automatically shut off by the speed indications loss)
- took pitch up to ~11° (i.e. more than twice what was required in the procedure)
- didn't adjust thrust until much later.

Scrupulous application? Huh?
So much for ALTER's credibility...

Lyman

AZR Also, (forgetful) I am not meaning the 'g' demand LAW, but 'g' PROTECTION as the problem.

It is assumed there will be emphatice accelerations in recovery. The elevators obey the g prot, and just when we think we are recovered, oh oh, some up elevators......damn. The recovery was not botched by the pilot alone, eh?

AlphaZuluRomeo

Where did you find those 4° AoA? During the whole stall, the AoA remained above 30°...

No. No. Definitely no.
When stalled, diving is required, unless you got enough power (thrust) to counteract your aircraft weight and drag @ high AoA, which is NOT the case of any airliner.
The standart recovery from stall is to dive, to trade altitude (which must be a secondary concern, then) to a lesser (and flyable) AoA.

Unfortunately, when pilots believe something that is not really reality, eventually planes crash...
"situation awareness" ; rings any bell?


Argh. Once again, the purpose of the 'g' PROTECTION is to protect the aircraft structural integrity. Unless you imply that structural failures (like: loosing a wing or two, in the worst cases) are better...

GarageYears

Bearfoil:

Sans wing lift, I presume you believe the thrust of the two engines is somehow going to haul the 200 tons this aircraft weighs up in to the sky? OK, so even if we assume that the wings are still producing some lift (say 75%), that still leaves 50 tons...

Once in the stall, the only valid recovery is to reduce AoA and regain wing lift. Pegging the throttles to the end-stops is only going to induce more NU, which is the opposite of what was needed.

The harpooning was done by the PF in the first 30 seconds - pitch up, climb, loose all the necessary energy to FLY. What happened after that was futile, since the single most important issue was wing-lift... it was gone.

PF demanded NU, the aircraft continued to deliver, the THS was 'requested' to help out with this NU demand. I do not subscribe to any other way of explaining what happened. Without the pilot NU input, there is no THS NU.

Where do you see any evidence to support this? The THS was not 'planted' NU until pretty late in the game, certainly way past the point the aircraft stopped flying and went ballistic.

HeavyMetallist

There are two great mysteries in this thread:

1. WTF the PF thought was happening and why he did what he did
2. WTF people continue to reply to bearfoil/Lyman/whatever as if he/she is trying to engage in a meaningful dialogue rather than just trolling

Not sure which is the more inexplicable.

Clandestino

We might. Highly loaded, extremely efficient, high Mach no limited wing goes over 45° AoA - and it doesn't spin in the process!! This could even be below-garden-variety stall.

Contingent on final analysis, we might call it FCIMDS: flight controls induced and maintained deep stall.

Engine power is meaningless, if not compared to weight. It also falls off with altitude.

If we only could make this solipsism true, we'd get rid of the CFIT once and for all.

Like having all instrument except speed working reliably? Forget it - it's already patented.

No SAS on FBW Airbuses.

It was considered probable. Your statement is not true. Airbus can operate with simultaneous (long) erratic data coming from redundant sensors. It will operate in degraded mode, though but aeroplane will be certainly able of making it to stop on the runway in one piece.

Bingo. So attitude. So altitude. So heading.

Sure there are but only one is correct: smooth and precise. 5° might be 4° to 6° but never 12°.

So we agreed that your question "what do you do when feeling G" was irrelevant in context of instrument flying? That those who fly be feel when robbed of external visual reference more often succumb to illusions than not?

No sir, I'm not even close to perfection but my striving to achieve it keeps me within tolerances required to stay within the bounds of controlled flight.

And that is exactly why not everyone can be a pilot. Anyone can do my job when everything is going just fine. I was selected, trained and paid to quickly and correctly identify and perform the correct thing to do when things go pear shaped quickly and unexpectedly. BTW, if you fumble with QRH and reach 5° AoA in level flight you will be at so low mach, you'll get no stall warning at 5°. That is provided your stall warning system has valid mach input to adjust its warning threshold. If not - remember that stall warning is not stall itself. Yet.

We don't call it magic sir. We call it "aerodynamics" and "performance". I admit it must look magic to someone unfamiliar with either, just as instant light at flick of the switch would look magical to medieval man.

Thank you for your kind compliments, sir. I'll certainly let my effohs know how lucky you consider them to be. I wish you all the best for your graduation.

Correct, it's called partial panel flying, I did id too during my training and IMHO loss of horizon was the most difficult to handle of all partial panels. Good thing nowadays I have four independent horizon references in front of me. Head-up Guidance System, if you wonder what is fourth.

AlphaZuluRomeo

@ HeavyMetallist:
1st mystery is to last long I'm afraid.
Clues for the second are:
- it may be fun (if kept short ; when it becomes too lenghty... BOAC perhaps has some spare application forms?)
- more seriously, it's healthy to challenge alternate theories, in the hope that "uneducated" (no harm intended) readers don't take them for "real-because-no-one-said-otherwise". At last I hope so...

@ Clandestino:
"IMHO loss of horizon was the most difficult to handle of all partial panels"
I don't doubt it for a second

Lyman

Garage

"SANS WINGLIFT"? Pardonnez MOI? Something has stabilized her rapid descent at 100 knots...... DRAG, then, not lift. As you will.

The approved and trained recovery from STALL warning was working, it shows that in the traces. All that was necessary was to tweak it. TOGA, check. Maintain PITCH, oops. Find 4 degrees AoA (She did), keep the Power up, and wait. That is for 1000AGL, don't you think with seven miles of sky beneath her, it would be even easier?

She did not "Break", evidently? Mush? Whatever, she flew brilliantly. If, at the STALLSTALL each time, the PF had simply maintained the current AoA, and not PULLED FULL, who's to say? And that is with a dancefloor sized plank in back and an aft cg.

clandestino POWER is meaningless? It is what you got, and it better mean sumpin' "What a Pilot believes is his reality" You doubt that? It is the raison d'etre IMC, non?

180,000 pounds of thrust is not two hairdryers in miladies dainty fingertips. It is the reason twins can fly where they do, with great confidence. It is also the way to save the bacon, and that isn't me, that is AIRBUS talking.

PF had the skills, he did not have the confidence, nor the training to be patient; The unacceptable part of this deal is the lack of preparation on the part of the crew (not their issue), and the fear used as a backstop for engineers to look clever, and beancounters to buy the new Bimmer.

She flew brilliantly, right to the end. 4000 feet? I would not put it past a crack crew and less than moronic design of THS and g for gd PROTECTION.

UA means emphatic accelerations; to be expected. Not the time for clever people to protect the airframe from crinkled skin via g "Protection".

IMO

glad rag

AF447 investigation

Watch the short video and inwardly digest.

JenCluse

Apropo nothing other than a feeling of general uneasiness regarding operational standards . . .

Years ago I was the only F/O on a series of extended-endurance supply runs (on L-188), rostered with two Capts and a very young me. We rotated on route. I can still recall my complete awe at being dumped in the skippers seat on first crew-change ex-dept on the first trip. The wonderment, the confusion, the uncertainty as to who was in command. (He, the 2IC minor-god in the F/O's seat was that, of course, but it wasn't spelled out), and, it being after a hasty line training period, the daze I felt myself in, and my eventual engagement for that bit of the trip with the flight engineer (yup) on the details and ramifications of the 7 prop-stops used on that type. But no empathy for the aircraft, or the task.

I can relate too well with the so-low time P2 (P3?) in the F/O's seat. The grip on the stick would have been . . .

With an enquiry in place I think I had better stop here, other than to say that, with 2 skippers, the situation we have tried to deconstruct here for so many months, and which those in AF447 had just 3-odd minutes to resolve, would most likely have been handled otherwise with just one high-time driver at hand, and that in the end I suspect this will be another result similar to the ANZ Antarctic prang, which fundamentally resolved to management disassociation from operational considerations.

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