Originally Posted by
CONF iture
Report 3 itself mentions that the alternate law adopted was alternate 2B and it did not change again subsequently.
In the meantime, I observe that the Abnormal Attitude Law trace is not represented in the FDR data we've been given.
Yes, and I don't see why it should not be there, even if it is a flat line. Perpignan report has it shown (well, the idividual pitch/roll law transitions are). That report also has better quality images of the traces.
From my personal experience, I have to figure why the trim stopped around 12 deg UP and why it did not later on follow my full fwd request on the sidestick ... ?
My bet would be on abnormal attitude law - entered based on AOA threshold. However, it would depend on how you got to the stall - presumably something was failed to drop you out of normal in the first place, can you tell us what was failed ?
Abnormal attitude law apparently
doesn't give the "use man pitch trim" warning, but
does inhibit autotrim, (and yes, that makes no **** sense to me either) which would fit with what you saw.
447 didn't trigger abnormal attitude because the ADRs, providing the AOA values, were already rejected by the FCPs due to the previous failures.
Perpignan did show the "use man pitch trim" warning (whether they saw it or not, who knows) because they failed all the way to direct law first. After that they then ended up back in abnormal attitude (which also doesn't make a lot of sense to me - pretty sure direct law is already full authority bar g-load protections, so why if already in direct would you need to switch laws to enable a recovery
).
I guess after schipol, bournemouth, perpignan, etc., trimming needs to be part of stall / attitude recovery, whatever type you are on. Autotrim-stops-trimming (after trimming up into stall) is not a type specific problem or mfr or fbw specific (I don't think the 737 gives a warning on it either ?). I don't think it's going to be an easy one to solve (by engineering) either.
Also Conf, out of interest, presumably you flew alt-law in cruise in this sim - how did you find the pitch-normal / roll-direct combination ? As a non-pilot looking at the engineering of it, the control laws look mostly like sensible degradation, but that combination stands out as ugly - fly a different way in each axis! Is it really that bad hands-on, or is it ok ? [Clearly PF on 447 didn't find it ok....]