18 ms·
An AoA disagree indicator was an option. But it was never an option for this to disable MCAS, as this would have resulted in a change of the flight characteris
by mhandley 8y ago
An AoA disagree indicator was an option. But it was never an option for this to disable MCAS, as this would have resulted in a change of the flight characteristics that would have required training.
- erentz 8y agoOh! thank you I didn’t make that connection.
- michaelcampbell 8y agoWould a disagree indicator be an option without the second sensor? With what would it disagree?
- mhandley 8y agoAll 737s have two AoA sensors. The left one feeds the left air data computer and the right one feeds the right air data computer. The AoA disagree indicator displays when the two disagree, but is optional and was not fitted on the planes that crashed. The old version of MCAS only uses one AoA sensor as input, even if the AoA disagree indicator was fitted. It does, however, alternate which of the two it uses with each flight.
- ramraj07 8y agoIf that's true (that it alternates between the sensors each flight) then it's extremely obvious that a business decision was made to only use one sensor at a time.
- lagadu 8y agoI fail to understand how is the disagree indicator useful, considering the MCAS system will use the same AoA input regardless of disagreement. Is it useful for some other function?