Machinbird

Gatbusdriver
Gatbusdriver, welcome to the fray. During your training, have you flown in ALT 2 law, or are you on the little Airbus? We are drafting all able bodied bus drivers to try to answer this question.

My personal experience with the USNavy peg, cone and vane type AOA sensors is that they would come alive in a definite breeze, perhaps 10 knots. A vane type that needed 60 knots to be reliable would be a sticky one in my book.

spagiola

True -- once the rate of descent stabilized at some -10000fpm. But shortly before that, they'd actually been climbing, so at some point there was a heck of a vertical acceleration, and for that period the description would likely hold true.

I can only hope that that moment passed quickly, because it must have been terrifying.

Mr Optimistic

Well if gaining vertical speed the seat will push beyong 1g to accelerate the Pax. When the vertical acceleration becomes negative the seat will push up at less than 1g. If the vertical acceleration exceeds 1g down, and only then, will Pax leave their seats and be pushed down by the seatbelt.

Garrison

In French assister means to witness or be present at an event.

Machinbird

In referring to the Speigel article.
Hüttig is not without bias in that he provides technical assistance to the victim's families and thus probably has economic interests at play.

The description of the conditions inside the aircraft on the way down are a bit overblown. Although the nose did get pretty high in the air, the maneuvers suggest that cabin environment was close to 1 g. Probably more unsettling would have been the wing drops that the aircraft experienced. Not so bad as a roller coaster ride though.

Biggest fault with the Spiegel article is that the aircraft was "doomed" when the trim ran up to 13 degrees. If the crew had run it back down to near normal, this long thread would probably not exist and there would likely not exist a victim's family group.

There are a lot of training issues sticking out of this mess, and not all of them appear to have originated with AF.

takata

The meaning of assister is related to context.
1. être présent (participer) = to be present at something
2. aider (seconder, secourir, concourir, dépanner) = to help someone.
Where it is quoted from?

Garrison

"Entre 1 h 59 min 32 et 2 h 01 min 46, le commandant de bord assiste au briefing entre les deux copilotes..."

from the BEA interim report

sensor_validation

The comment in the BEA statement which was translated into English as "the Captain attended the briefing between the two co-pilots" - maybe trying to read too much into the wording - would expect the Captain to lead the briefing? As JD-EE pointed out above maybe this statement just confirms there was a formal handover as required, nothing more.

glad rag

Absolutely.

Garrison

Machinbird:
Agree entirely. If it's true about the Captain recognizing that the airplane was stalled, then everything comes down to that trim wheel -- unless, of course, the A330 turns out to have an unrecoverable deep stall mode, which I very much doubt. But if he said that as reported by Spiegel, why did the PF not react with an AND command? Oh, maybe that's where the AND command does occur -- but is aborted because of the stall warning. What a mess!

Capn Bloggs

Does it? How about a system where if it is not giving a reading within 16°AoA, it signals a stall? Say it is pointing "to the ground" whilst the aircraft is airborne. What do you reckon the crew needs to know? That aircraft isn't flying ie it's stalled. It doesn't matter where the vane is actually pointing.

But in this case, just when the crew needed the most "reminding" (and who would have not been confused: VSI off the clock going down, but with speed tapes on nothing, "knowing" that only a couple of minutes before they were giving duff gen), the stall warning silenced. Had it kept screaming at them, maybe their confusion would have eventually been overcome and one of them would have stuffed the nose down to recover the thing.

sensor_validation

For lots of detail on the AoA vanes see the Perpignan crash report. The vane may indeed generate a "local angle of attack" but "As the fuselage disturbs the flow of air, these measurements
have to be corrected to obtain the aeroplane angle of attack." I wonder if its the compensations that limit the use at lower speed, but then where does the speed come from?

milsabords

This does not look like good logic: if they have evidence that the ac is stalled while there is no stall warning, they should ignore it when it sounds again.

falcor

I previously asked the following questions:

1. If/when the plane kicked into Abnormal Law, what warning or message would have been visible or audible to the pilots?
2. Why was there an ACARS message about the transition to Alternate Law, but no ACARS message about any other change in Law (e.g. Abnormal or Direct)?

mm43 directed me to A340 / A330 Control: flight & laws
but having read through that, I must be blind because I don't see the answers to my questions!

It seems that whether or not the plane was in Abnormal Law (and hence had no autotrim - making the THS "frozen" at 13 degrees unless manually adjusted) is important in understanding whether the pilots had a chance of pulling out of the stall once they started putting the nose down (after the captain returned to the cockpit).

So far, it sounds like we are inferring that it was in Abnormal Law, owing to the AoA and speed crossing the specified thresholds, but can this be shown explicitly through a message or recording? And if not, why not? It may be an important point, so it would be nice to have certainty. There appears to be no ACARS message about any law other than Alternate - does that mean that Abnormal Law doesn't generate an ACARS message...?

The other question, which some others have touched on, is whether the pilots knew they were in manual trim mode. From the "flight & laws" link above, if in Direct Law the pilots will see "USE MAN PITCH TRIM" on the PFD. Is that also the case in Abnormal Law (it doesn't explicitly say in that link)?

MurphyWasRight

Sensor validation:
Th 60KT limit may also be an almost arbitrary "safe" limit withe the rational that if airspeed is that low you are not flying anyway?
This would also help eliminate spurios alarms durinfg landing.

takata

Right. In this context, "assister" only means that he was present during the briefing. He could have either contributed to it or remained totally passive, it doesn't tell it.

You guys are again focusing on press "leaks" which doesn't look more "informed" than all the previous ones. The statement that FO2 (Pierre-Cédric Bonin) was the PF is clearly doubtful.

HarryMann

I've got to say Garrison, I feel that's likely true.... especially if less than TOGA thrust was also selected.

It is a very remote possibility I suppose, that the PF was under 'some impression', at a base response level, that recovery from a stalled condition does not require a consistent and nose-down pitch .

If so, it's highly unlikely that Captain M. Dubois would have followed that course of action, and must have realised having made his way to the cabin, pretty well what sort of situation they were in, irrespective of instrumentation

bearfoil

howdy. PF gets Stall Warnings; a warning is not the same as the real deal.
His training (prior to AB "Stall Warning Recovery" "modification") was to fly through the warning losing little if any altitude and use power to accelerate.

A warning given at the break would not be a warning, it would be an annunciation. Having never experienced a full stall, he would likely not anticipate it by definiton, as he has had no training how to recover it, so all that would happen is an unanchored 'anxiety'. In other words, one flaw in "Display" is a gotcha without recourse. Not very nice, Miss.

Tailspin Turtle

I have thought from the beginning that a deep stall was very unlikely, but it appears that the pilot flying managed to unknowingly stabilize the airplane in a very similar flight condition. I don't know why he changed from a perfectly good pitch and power setting to get so slow, but at that low a speed, the engines were probably providing a goodly amount of nose-up pitch (along with the stabilizer trim automatically coming in to "help" him keep the nose up) so the normal pitch down occurring at stall might not be evident. Other than airspeed, which he has reason not to trust; angle of attack, which isn't displayed?; and an aural stall warning, which is apparently inhibited, how else does he know that he's stalled? What he knows is he has the throttles pushed up, the airplane pitched to 15 degrees or thereabouts (16.5 degrees) which is a familiar number for powering out of a problem, and his rate of descent is at the bottom of the tape and the altimeter is a blur, both high-order attention getters. Who among us wouldn't be confused as to why the airplane was descending instead of climbing and desperately pulling back on the stick to make it climb like it always has before?

bearfoil

So his forward stick and decrease in AoA may have gotten him on the way to recovery, but do we know the decrease in AoA was not just the a/c dropping her nose after stalling?

If the Captain did re-enter and shout, or command, likely it would have been something along the lines that precipitated a "just about" recovery.

You know, this discussion, read with patience, will eventually get to within 90 per cent of the actuals.