Originally Posted by
gums
I do question how many of the pilots had previously flown a pure FBW system while the control laws and so-called "protections" were being implemented.
I think I recall a few of them had been involved in the Concorde "minimanche" project. Concorde used an analogue FBW system rather than a digital one, but it was FBW nonetheless.
I also question how many tweaks and changes were made during the prototype phase and such - those suggested or even demanded by said pilots after actually flying the beast at the limits of those "protections"
Probably several - but the process was not particularly antagonistic - remember that the prototype would have been flown in Direct initially and the test pilots would have confirmed those limits.
( how I absolutely hate that term - grrrr).
Why? "Limit" doesn't cover the functionality, and the best example of that is Alpha Floor, where the system commands maximum thrust to prevent stall.
In fact the only accident related to Airbus FBW occurred when the Captain turned the protection into a limit by permanently disabling the autothrust function.
Folks can point out that my ancient jet was not designed for the same operational needs and requirements as a commercial airliner. Nevertheless, just divide our "limits" by certain values and you get the 'bus "limits".
Fair enough, but that doesn't change the fact that the fundamental requirements are different.
We did not have four distinct reversion modes and a fifth if you count manual THS commands and I guess rudder. Fer chrissakes, look at the 'bus reversion chart in the manual! 26 footnotes! AoA alone has three, plus note (a).
The specifics underpinning these modes do not need to be memorised in order to command the aircraft safely. The only rule that cannot be forgotten is the lack of hard protections (or "limits" if you prefer) outside of Normal Law. As far as I'm aware there have been zero incidents of ABNORMAL ATTITUDE or MAN PITCH TRIM ONLY on the line.
Convince me that the AF447 PF was considering all those exceptions to the "rule".
He didn't need to be - staying inside the envelope was all that was required.