That leaves me more confused than before.
You're not the Lone Ranger, Lone Wolf. That AAIB narrative has a number of confusing statements and has me scratching my head.
Here's the first two:
The commander could not remember the sequence of warnings but he did recall being unable to reengage either autopilot which prompted him to make manual control inputs. He also remembered seeing an ‘Alpha Lock’ warning displayed on his Primary Flying Display.
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The indicated airspeed dropped below VLS (the lowest selectable) as the aircraft climbed and the commander took manual control of the aircraft because neither autopilot would engage.
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Confusing to me because I would think a 5000+ hour on type Captain ought to know that 'alpha lock' is not displayed on the PFD and is slat/flap related.
And a 5000+ hour on type Captain ought to know the autopilot cannot be re-engaged below VLS.
Next taken together confusing statements 3, 4 & 5:
For 18 seconds after the autopilot disengaged the aircraft remained within 200 feet altitude of FL 360 but once AoA law was invoked at 14:21:50 hrs, the aircraft’s attitude began to pitch nose-up.
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and automatically disengaged the autopilot. One second later
the TCAS issued an RA with a “DESCEND, DESCEND, DESCEND”audio warning.
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Such was the vigour of the A340’s climb in AoA law, the aircraft could well have climbed through FL 363 (thus provoking a TCAS RA with revised software version 7.0) in a very short time,
A TCAS DESCEND RA evidently WAS indeed provoked within 1 second of A/P disengagement, but for 18 seconds the 340 remained within 200 feet of FL360 (the 330 encountered a 200 foot altimeter drop), so what's the point to be made with the 'climb vigour' and 'could well have climbed thru FL363' statement. RA occurred without either of these. Time to do some pilot stuff with the SS.
And here's the kicker (board statement):
The commander’s reported sighting of an ‘Alpha Lock’ message was probably an alpha floor warning on the flight mode annunciator portion of the PFDs.
Read A33Zab's previous post on these functionalities (alpha lock 'pulses' bright/dim on the EWD slat/flap display, alpha floor is a PFD FMA steady indication) and you can see why I'm confused. Of course I don't have 5000+ hours on type.
And as Chris Scott alludes to, the DFDR traces are almost worthless....it would be interesting to see a TLA trace, 'cause the whole thing is screwy IMO.