Originally Posted by
MemberBerry
Actually it can take longer than 40 seconds. For just the 2 first steps out of 3. From one of my previous posts:
You could do all 3 steps in 5 seconds if you had no communication with the other pilot and didn't wait at all between the steps. But that doesn't sound very wise.
Later edit, actually I think that's one of the mistakes of the Ethiopian crew. They executed this checklist too hastily and they skipped the step about disabling the auto-throttles. If they did that, they probably would have payed more attention to their speed and adjusted it manually as needed. Instead, the engines remained at 94% until VMO, when from the FDR trace it seems the A/T lowered that to around 90%.
To be fair the mentour pilot video was done in a "teaching/demonstration" mode, a real crew would have probably done it twice as fast.
Skipping autothrottle off step is significant, although much earlier on some pilots posted that simply chopping the throttle in their condition could have undesired effects and had to be done with some fitness.
In any case they were still under VMO when the cutout switches were actuated, have not seen any hard facts on what speed would allow manual trim given the trim state.
The real problem was using cutout before the AC was in trim. It is possible that once the FO called runaway trim the pilot jumped to that thought even though he was successfully trimming at the time.
It is not clear that the ET pilots were fully aware of the revised procedure, yet another painful hole in the cheese.