Originally Posted by
kimChee
Here's a video of older 737 simulator with runaway stabilizer - starts just before 3 minutes in -
https://www.youtube.com/watch?v=3pPRuFHR1co
Think for a minute (no you don't have that long...) - how fast can the automation incorrectly trim and put you in a nose-down/high speed position. What's the best reaction time one could expect from a pilot to recognize what is happening and take the appropriate action?
Then, think - now you've got to manually crank the trim back, while still flying the plane manually and taking care of everything else at low altitude --- I'd sure like to see a simulator video of this situation with the Lion or Ethiopian situation and see how reasonable it is to expect a flight crew to deal with this situation....
An excellent find.
One of the early drills in the ancient Lear 24 was a runaway trim. Almost all check rides in the 1970 had a runaway trim exercise. A recent comment from my airline pilot friends was: that a runaway trim problem was a common drill in the flight simulator.
I was shocked to find out that pilots did not certify for a type rating in a 737 in a simulator and that there is not a 737 max simulator for training. Even in the 1990 a type rating could be earned in the flight simulator. A very good friend who is still flying corporate attends Flight Safety at least 3- 4 times a year.
Procedures training in many aspects of aircraft operation is possible on a PC. Why no simulator course?
As your video clearly shows: Hand cranking a manual trim wheel does take effort to a control pitch down. and it does take time to crank the trim wheel. I believe the Boeing engineers thought that multiple systems failures causing the MACS to pitch down would be extremely rare. An existing procedure was covered in the aircraft manual and drilled in the simulator a " runaway trim" would cover the MACS trim runaway. But recent findings indicate that MACS nose down trim does not react exactly like "runaway trim" with a constant nose down action.
The question that remains for me is what failures triggered the MACS on the Ethiopian 737 MAX. The Lyon Air MACS actuation seemed to have occurred after a miss diagnosis by the maintenance department and the failure of the previous crew to pass on the corrective action they took to correct the problem on the flight the night before. After a flight like that most carries would "red tag" the aircraft until a test flight.
The Ethiopian Airways also in for inspection the night before the final flight. I hope those involved in the investigations can get to the cause of the failures and do not get caught up in the legal- criminal blame game. I trust those involved in the design, training and repair of the 737 MAX with be open and truthful about what was that operational status and what " adjustments and inspection" was done before the final flights.
I am doing what I said I would never do... Make a conjecture before all the facts are in. In my case a little bit of knowledge is dangerous. So forget what I said.... Cheers.
The crash of the 2 new aircraft was a true tragedy. My condolences go out to the families that lost their loved ones.