Originally Posted by
CurtainTwitcher
The bullet points are:
- Comparing AoA signals could generate a warning.
- AoA warning would be outside an iPad training path for 737NG--->737MAX and could possibly involve a simulator session.
- A simulator session would incur a $1 million penalty per aircraft for Southwest airlines.
- Boeing choose to categorise an uncommanded MCAS runaway as only "major" and not hazardous
- Therefore Boeing choose not compare AoA
A bit out of order. The FHA said it was a major hazard so didn't need the comparison. That came first.
The AoA miscompare alert was already there* but MCAS didn't need to use it per the FHA. You don't just add stuff with no requirement and the FHA didn't support adding the requirement.
*I know the alert was not enabled. As discussed it was supposed to be. But again, it wasn't considered serious enough (FHA again) to rush the update.