Quote:
Originally Posted by
Winnerhofer 
Once the plane is in ALT, it remains in ALT until overseen by maintenance.
Not exactly - Alternate Law is only "latched" (as in cannot revert to Normal) if the divergent conditions last for more than 10 seconds. A transient condition of less than 10 seconds will allow for a return to Normal Law in flight.
In this case the pitot tubes were blocked for too long and Alt2B was latched.
Thank you both.
I have been lurking on the forums a while, but left the discussion to the experts. So with the big disclaimer that this is all coming from a non-pilot, there is one aspect that has been standing out for me:
It is astounding how much into a 'tunnel visoned' Bonin must have been to miss that he was having the plane in climb for a total minute. It was night outside and it seems he left all the ECAM trouble shooting to his partner, so his eyes must have been on the PFD. Yet he seemed to ignore the altitude display, with the numbers constantly changing, aswell as the the climb/sink rate rate gauge.
After around 25 seconds in, at FL 368 Robert tells him to mind his height, and Bonin explicitly acknowledges it ("
Ok ok je redescends"). Some nose-down inputs on the stick follow, but, for a lack of better phrase, the stress must have pushed "height awareness" out of his mind again, as he continued climbing up to finally FL 378.
It seems during those 60 seconds pre-stall a simple realisation like "
My supposed FL is 350. I am 2000 feet above my FL, I must descend!" never materialised.
In this thread and in the BEA report the term "startle effect" is brought up several times and it feels to be spot on. It's very hard to read the transcript and not think "If only Robert had been more insisting after he noticed the wrong attitude".