Originally Posted by
jimjim1
Flight tests on a modified B737 max [one full week - at Boeing Flight Test Center]
- MCAS operations (nominal behavior)
- Flight without MCAS (including high speed turns and stall)
- Scenario of stabiliser runaway (uncommanded MCAS activation, manual trim wheel forces)
- Approach to stall with autopilot engaged
The answers to some of these might be obvious, but I thought I'd ask anyway . . .
It's not clear what "uncommanded MCAS activation" means. Do they mean MCAS is activated even when the FCC is receiving consistent AoA values below the activation threshold? If so, how do they do this in a flight test? Are they going to fly an airplane with intentionally corrupted memory, which is what they apparently simulated in the EASA-requested simulator scenarios in July?
Why does the uncommanded MCAS activation scenario involve "manual trim wheel forces"? By now, every 737 pilot in the world must know (even if they didn't know after the Emergency AD) that the correct response to an incorrect MCAS activation is to fully neutralize control forces using MET and THEN place the switch in the CUT-OUT position. Doesn't requiring demonstration of the manual trim wheel as a re-certification requirement rely on the assumption that pilots still cannot be relied upon to perform this procedure and will still CUT-OUT electric trim with the airplane in an out-of-trim condition?
What is the regulatory basis for demonstrating recovery with a manual trim wheel when the published recovery procedure is to use MET before CUT-OUT? Obviously, fully FBW systems don't have a manual wheel and rely entirely on electronic controls to recover from a FCC-induced runaway trim condition. Why is the use of MET in the 737 different?
We know, based on the ET302 accident, that the manual trim wheel cannot be used to re-trim from certain trim positions beyond certain airspeeds. Presumably, EASA re-certification is going to require successful use of the manual trim wheel up to some lesser degree of out-of-trim/airspeed condition. Is there a regulatory basis for deciding what that condition must be?