Originally Posted by
hans brinker
Just like MCAS is only active at high AOA.
So what happens when the WOW or RA or whatever single source B likes to use for critical systems breaks.......
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.