takata Quote:
"first recorded ACARS"... no, they are unsorted and should be sorted in order of priority, plenty are triggered at the same time.
AP & A/THR are kicked off because the aircraft go to ALERNATE LAW2 as a consequence of the unreliable AIR DATA, etc. No exceedences of forces acting on the aircraft are needed to do that, but it certainly won't help for crossing a [undetected?] tropical CB.
See above post, the ACARS are now published in their integrality.
S~
Olivier
My point being, crossing a (undetected?) tropical CB would, in addition to acting on all the aircraft's axis, also raise hell with the air data, especially in terms of miscompares. A 100mph vertical gust equals about 9,000 fpm. In a fast-building CB the measured-by-water droplet vertical velocities can approach twice that....18,000 fpm, and the real updraft speed (since droplets move more slowly) even higher.
There isn't an aircraft designed that can cooly transition though something like that even with all systems functioning. Inadvertent CB Penetration 101 includes not only disabling any altitude hold fuction and accepting altitude deviations, but also accepting radical airpspeed fluxuations, not only because the indications may or will become unreliable in relation to true aircraft speed, but also because the multiple Air Data systems may become unreliable in relation to each other due to unequal forces acting on the aircraft.
Meanwhile, with these unreliable and conflicting indications, a hand flying pilot, possibly in severe turbulence, must still maintain the reality as it exsists out on the wing...airflow somewhere between low-speed buffet and mach buffet, with the margins between them fairly close at high altitude. Overspeeding is a world of hurt just as big or bigger than stalling. And at high altitude and weight the pilot must stay within those close buffet margins while not executing anything near the rolling action he could at lower altitudes to deviate his course around more weather or counteracting turbulence and/or dutch roll. To do so at that high altitude risks a load factor-induced stall through a raised low-end buffet margin.
Worst of all, all those conditions can and do exist in the clear air above developing CBs, and inside those that don't contain enough moisture at that paint clearly or produce icing of any significance.