AF 447 Thread No. 5

[peefactor]

Apologies if I mention things that were covered already.

(*I speculate*) Could the PF's initial response to pitch up have been to regain his original altitude of FL350? - Perhaps his altimeter showed a gradual loss in altitude as blockage occurred?

(as happened in previous events. See pg48 and pg51 of the following document: http://www.bea.aero/docspa/2009/f-cp090601e2.en/pdf/f-cp090601e2.en.pdf)

The PNF's action of switching the F/O displays to ADIRU 3 info seems to also suggest he felt ADR2 was less reliable.

Later on, after the captain is in the cockpit:

2 h 12 min 15 to 2 h 12 min 19
CAP: Là je sais pas là ça descends
There I don't know, there it's going down

His comments coincide with the AIR DATA and ATT-HDG selector being positioned to 'CAPT on 3'. Seems like a lot of confusion in the cockpit about what is happening with the altitude. The airplane is pitched nose-up, by this stage the PF claims to no longer have any V/S indication, and there continues to be doubt as to whether the airplane is gaining or losing altitude.


2 h 12 min 27
PNF: Tu montes ...
You're going up ...

PNF: Tu descends descends descends descends
go down go down go down go down

2 h 12 min 30
PF: Je suis en train de descendre là?
Am I going down?
(Pardon my French, but could the 'là' be the PF referring to PFD1 or the ISIS? As if to say "those instruments there say I'm descending???"

PNF: Descend !
Go down

2 h 12 min 32
CAP: Non tu montes là
No you're going up there
(WHERE does it show them climbing??? I am not so sure he is referring to pitch attitude)

2 h 12 min 33
PF: Là je monte okay alors on descend
There I'm going up ok so let's go down
(Once again - what is indicating to him that they are going up?)

There are only two things which I can think of which indicate up and down in an airplane (excluding the V/S indicator).
1) Pitch Attitude (in which case the whole discussion of up and down is in reference to attitude).
2)Altimeter information (in which case one of them is indicating an increase or constant altitude, while the other(s) indicate a decrease in altitude.

I am baffled by what could have been happening, and as the ADR2 data is not recorded by the FDR it leaves us wondering whether it was behaving in a similar fashion to ADR1 and 3, or doing something else. Otherwise...how could there be so much discussion about whether one is climbing or descending?!?

I strongly believe the captain's comment was in reference to this conflict of information:

2 h 12 min 44
CAP: (…) C’est pas possible
It's not possible

And I would be inclined to say the same - I don't think it's possible for one ADR to somehow be frozen or to be indicating an increase in altitude. Nor do I know whether it's possible for IR2 to be displaying different attitude information compared to IR1 and 3. But the entire talk of climbing/descending leads me to envision such scenarios.

As a final point - I do not doubt the experience or professionalism of the crew. I believe they did their best with the information that was presented to them, and I don't think it was as simple as the PF simply being 'behind the airplane' and not noticing where he was pointing the airplane - it's possible, but I imagine there's more pieces missing to this puzzle. Nor do I think he was chasing the intermittent FD bars. I think a pilot with his experience on the Airbus would know not to follow the FD bars blindly - it would serve no purpose in such a situation and I'm willing to bet he was aware of that.

PS - If it wasn't mentioned already, the airplane switched to Alternate 2 - meaning roll control was DIRECT. Maybe this contributed to his 'over controlling' in roll.