BOAC

- while I fully agree that, as with the PGF A320, power reduction would have aided recovery, I think you are confusing pitch attitude with AoA? - it is AoA that stalls a wing, not pitch. Pitch attitude is not in reality relevant to 447 from 38000' down. Even when the pitch attitude fell below zero the wing, I think you will find, was still fully stalled and being kept stalled. It is extremely straightforward to stall an aeroplane at a very low power setting if enough nose-up force is applied - otherwise airtest stalls could never be done.

Lyman

AF don't fly AoA, Pitch was not inconsistent with GA, and there was no sense of a/c orientation other than that. It seems to me, they were unaware of the AoA disaster. Captain returned walking up the aisle to the Cockpit door, and he makes no comment re: deck angle, so why do we assume it was an issue, to them, the only ones who mattered. And, if not, ample evidence exists to show how they lulled into "other than STALL".

Inertial attitude from FDR, as well as Inertial speeds and accelerations were not available to the flight crew. The VS confusions are an example. It is a difficulty to resist a simplistic opinion, I will admit. Vertical speed, airstream noise, and an unsussable deck angle (due comfy g) make an either/or seductive. Rapid nose down descent, or mushy NU descent?

CHOOSE WISELY?

For that matter, the record of annunciations in the FDR do not prove they were displayed in the cockpit.

At some point, the realization must be that there may have been failures of electrical nature and mechanical, and that the crew were not privy to the nature of the failings. To assume that all evidence is fair, and balanced, as presented, obviously allows for some conclusions that cannot be supported. As yet, anyway.

BOAC

Lyman - I am forced to join the club and say I don't understand most of that

PuraVidaTransport

BOAC-
Point well taken. Indeed, despite the 25 degree reduction in pitch the wing was still stalled so you could say it was the pilot inputs (and resulting THS setting) that kept the aircraft stalled even without the thrust. Thank you for the explanation....

HazelNuts39

In the graph on page 111 of the english version on Interim report no.3, just below the V/S 'zipper' trace, is a trace indicating the source of the V/S parameter as being alternately IR and ADR. Although the IR part of the ADIRU receives the baro V/S from the ADR part, I assume that here IR means inertial V/S and ADR means barometric V/S. My question is: Does this trace only indicate what source the DFDR/DFDAU is using for the recorded V/S, or does this have implications for other systems, such as the calculation of FPA/FPV (note FPA trace lower down on same chart)?

Lyman

I got a bit ot in the other, so I'll bring this up here.

A question regarding V/S sel.

In autoflight, what is the purpose of a 5k fpm descent? The controls are sheltered by the FCM, so why a rate? Is a rate the way altitude is selected and input by the computer? Even in ALTERNATE LAW 2, later, the PITCH is doled out in bits, the RoA is acquired in pieces, not in DIRECT fashion? Is 5k an increment?

Also, re: AL2 PITCH. Not being DIRECT, we see the time it took to establish the climb.

So, After the STALL, is the PITCH still being incremental, vice "brisk"?

As in "Briskly NOSE DOWN, please." Or is the ship in DIRECT at this point, and if so, what are some control surface rates we can look for in a potential recovery?

Right, then. After a STALL, the computer input PITCH commands are lost, and the ship has DIRECT from SIDESTICK? Makes sense, one would want severe rate. To avoid, SECONDARY STALL?

CONF iture

I don't have the answer to the question, but as long as the VS takes its source on the IR, the recorded VS and FPA make sense. When the source is the ADR, both values seem to be erratic and unreliable.




The BEA is not that affirmative :

HazelNuts39

CONFiture,

Thanks for correcting me. If I had been writing an official report, I would probably have used BEA's words.

ChristiaanJ

CONFiture,
Sorry for being lazy.
What's the bottom purple trace in the graph in your latest post (the one degenerating into another 'zipper')?
Seems to say "Angle de Pente" (pitch flight path vector), but difficult to decipher with the lack of resolution.

Lyman

Since CJ doesn't read me, so he won't have a cow, isn't the Pitch FPV oscillating twixt 0 degrees and 30 degrees NU?

DozyWannabe

I'm reading you, but electing not to engage directly for the foreseeable, however for general purposes the pitch scale is oscillating between the bottom of the graph (i.e. an unreadable value) and 0 from the time the AoA becomes unusable, and between unreadable and max during the last few seconds, which indicates that the graph becomes meaningless after the AoA becomes unusable.

CONF iture

Correct CJ, that's the Flight Path Angle.

HN39,
I thought it was important to mention that the BEA wrote that word, especially as they did not mention the particularity of the SEL VS trace and they did not publish the AP/FD VERT MODE trace.

Lyman

Unreadable value? How's that, the x says -35 degrees at the bottom of the spikes. Matter of fact, it is at this point BEA claim the AoA at 35 degrees.

HazelNuts39

Lyman,
Minus 35 is the bottom of the graph, the bottom of the spikes are below that, not shown, hence their value is unreadable on the graph. The actual data points are shown as little dots (better seen in the original) when they are 'readable'.

GarageYears

Couple of pages back 10/14/11
The PF was NOT the 2nd copilot recently back from rest, but the 1st copilot and had been in the cockpit since take-off. This was discussed at some length earlier in the thread... While it may not be earth-shatteringly important, these small details resonate with me, at least, and lend a lack of credibility to much of what you post - if the FACTS cannot be kept straight, why on earth should your hypothesis be any more accurate? This is not the first fact that has been stated as such, only to really be shown to be incorrect. I appreciate the "thinking outside the box" mentality, but just for creditabilities sake, please keep the facts straight!

Lyman

Memory is not great since the stroke, so I apologize, and since retirement, I have no editor. Use what you can, if you like, or not.

Wish they'd give you the CVR, I'd be interested in what your thoughts are.

The audio record is greatly important, and without its presence, I don't think anyone can have a complete understanding.

Do you think Captain might better have kept at the controls, and taken third rest?

GarageYears

Yes, the audio signature background noise on the CVR would be very significant. Having heard 100's of hours of cockpit recordings, I find unusual cue sounds are pretty easy to identify. Hopefully the BEA have someone clued in on this.

Personally I am surprised the Captain choose to take his rest when he did - knowing the ITCZ was coming up and the weather less than optimal. However I have no knowledge whether this was Air France normal practice nor do I know what other major carriers do.

Dani

This is absolute normal practice in every western airline because every senior FO/cruise relief pilot/cruise captain can fully substitute a captain in all his tasks. Otherwise he wouldn't be cleared by training or the captain couldn't go to rest. Captains most of the time take the middle rest because that's the best one and he is enough tired to have a good sleep and he has enough time to prepare for the arrival. Well relaxed captain means good crew performance.

MaxJack

Dear Experts,

Could ice-build-up, at tail and/or wings, have caused the climb to FL380 or was it all due to PF inputs?

Dani

If you read BEA report No. 3, you find that parameters of steering overlay flight parameters nearly completly. This means that steering inputs have lead (mainly) to the outcome of the flight, not influences from outside. They conclude that the aircraft did not stall because of turbulence, failure of systems (other than the pitot tubes) or any other factor, including ice on the controls.