On 5/25/23 13:38, geneb via cctalk wrote:
That wasn't a software problem, that was a
criminally cheap management
problem - they deleted the comparator for the AoA indexer to save money.
Yes, but probably not Boeing's. AoA disagree was an available option
that most /airlines/ explicitly elected not to purchase. Part of the AD
was requiring that system, plus limiting MCAS authority so that if you
hadn't noticed the trim wheel whacking you in the side of the leg you at
least couldn't get into a situation where it would take three people to
overpower the combined trim and aeroloading forces, and notably, sim
time to review trim runaway procedures. It's not reassuring how many
crews got trim runaway wrong in the sim.
AoA disagreement on the B737 is weird anyway. Each AoA sensor drives
one half of the cockpit stall avoidance systems, so the way you
typically tell that a sensor has failed is when the stick shaker on one
side starts going nuts while the other one doesn't.
Honestly, the biggest blame here probably belongs on the doorstep of
Southwest.
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