Originally Posted by
tdracer
TCMA uses multiple air/ground sources to determine 'on-ground'. Default is air. It's resident in the FADEC software and DAL A s/w (which MCAS wasn't).
I'm not familiar with the specifics of the 787 TCMA, but on the 747-8 TCMA uses three radio altimeter and two WOW signals. At least three signals must indicate ground, with at least one each from the Radio Altimiter and WOW.
That is serious software verification.
So while it would be interesting to understand the details of the 787 runway shutdown, we can at least be pretty confident that it does not translate to an in flight probability.