Originally Posted by
safetypee
Furthermore, if the FAA knew of this inability (NTSB rep), then how could they issues a special approval for repositioning flights with empty 737 Max.Might the operators / unions have a view on this.
My understanding (not a pilot) is that if the stabiliser trim is set on the ground, and the trim cutoff switches activated before takeoff, then the aircraft should be controllable under normal flight conditions. Keeping airspeeds below 250kts would be an extra precaution.
The FDR readout for the Lion Air flight (JT043) prior to the crash (posted on previous page) looks mostly unremarkable (stick shaker notwithstanding). Following the initial oscillations, and after the cutoff switches were activated, trim adjustments were handled manually as per normal flight parameters.
Originally Posted by
GarageYears
Correct me if I'm wrong, but as far as I am aware, there was/is nothing stopping the crew from electrically trimming the aircraft nose-level (or high even) and THEN hitting the trim cutout switches?
Notwithstanding speed or any other factors?
Yes, I'm sitting here with 20/20 hindsight as many are happy to point out, but assuming Ethiopian WAS an AOA sensor high issue (which we still have no confirmation) leading to an MCAS issue, why wouldn't the crew trim NU electrically and then in the 5 seconds before MCAS would run again, hit the cut-outs?
- GY
Sources differ, and that was the advice from Boeing and the FAA (see my earlier post). There is a strong suggestion that the electric trim was intentionally restricted in power, specifically to prevent runaway nose up trim. This meant that overpowering MCAS this way was not possible, though it might have made a few degrees difference before they hit the cutoff switches. The recent simulator run reported by the NY Times last week, was not encouraging:
https://www.nytimes.com/2019/03/25/b...ion-error.html
Edit:
safetypee has the EASA warning.