2 ms·
The problem is: 1. MCAS failure produces an intermittent stab trim movement. 2. Boeing claimed that the stab trim runaway checklist should have been run and w
by cameldrv 8y ago
The problem is:
1. MCAS failure produces an intermittent stab trim movement.
2. Boeing claimed that the stab trim runaway checklist should have been run and would have let the crew recover.
3. Boeing's checklist only calls for action on "continuous" uncommanded stab trim movement https://www.satcom.guru/2019/03/taking-next-steps-while-awaiting-on.html https://www.satcom.guru/2019/03/taking-next-steps-while-awai... (second image)
4. Intermittent uncommanded stab trim movement is normal. The Speed Trim System and Elevator Feel Shift system regularly adjust trim, so merely seeing the wheels move by themselves is not cause for alarm.
5. MCAS is not documented at all in the flight manual, and the stab trim runaway checklist was not updated to address how MCAS might cause a failure necessitating its use, presumably to avoid the need for additional transition training.
6. MCAS is unreliable due to its reliance on a single AoA sensor.