ShyGuy

Looks like a constant 11 minute struggle with control yoke only trying to fight the automated nose down input from MCAS.


https://www.nytimes.com/2018/11/27/w...ir-crash-.html


It would seem the previous crew used the switches on the center pedestal to remove electrical power to the stabilizer and regained control manually. Unfortunately it seems this crew did not do this. The entire time, that trim wheel would have been spinning and spinning. It's sad they weren't able to just remove power to it.

Still hope they recover the CVR. Only that will show the human interaction, what they said, potentially what they thought, etc.

F4E Mx

It would seem there could be several reasons for a runaway stabilizer besides the failure of the AOA input. Isn't this covered in the simulator lessons? And what happens if the pedestal switch doesn't work? There is no clear evidence they DIDN'T try to actuate it. Is the circuit breaker marked to be able to positively disable the system?

WideRide

Not true...the B757 and B767 has adequate control authority such that the plane can be flown with the elevator inputs regardless of stab trim setting...including full nose up or nose down. It's not pretty and it's no fun, and it can take two pilots on the yoke as your arms get tired, but it can be done. I've done it in the simulator multiple times.

I was trained in both jammed stab full nose up and nose down-trimmed landings as well at my carrier.

I haven't flown a 737 since the -200 so I don't know anything about the MAX and its MCAS system.

sgrd0q

Boeing has a problem with the elevator. The elevator needs to be able to overpower the stab even if the stab is jammed full nose up or full nose down.

They need to redesign the elevator and the FAA needs to enforce their own rules and regulations.

The elevator not being able to overpower the stab is BS. Having to trim to recover from a stall as the elevator doesn't have enough authority is BS. Boeing knows it and tried to "fix" it by adding the MCAS to drive nose down stabilizer trim automatically based on the AOA. Oh, and to make sure it is effective they designed it so that the stabilizer trim commands are NOT interrupted even when the control column is displaced in the opposite direction. Oh, and they didn't bother to tell anyone. What can go wrong? This is total BS.

You can do more training to switch off electrical power to the stab, but that is not a complete solution. What happens if the stab jams fully deflected next time?

Interestingly, it looks like you can overwrite the automatic movement of the stabilizer by using the thumb switches (sadly no more by pulling up) so it looks like the MCAS trimmed the nose down, the pilot flying pulled up and trimmed up, effectively keeping the situation nearly stable. Looks like this repeated multiple times, but at the end they stopped trimming and ended up just pulling up which ultimately resulted in the loss of control.

F4E Mx

"...but at the end they stopped trimming and ended up just pulling up which ultimately resulted in the loss of control."

They stopped trimming because they ran out of trim? Seriously apologize if this is a dumb question.

NaKaTaTuNa

Where is the discussion around flaps in all of this? The theory around MCAS and pilot not understanding it and trying to counter it to no avail through trim is well rehearsed. If you look at the data the pilots had issues from the start but appeared to have gained some momentary control and altitude. Goes back to my theory that pilots probably responded properly to the initial airspeed and altitude disagree and as per MI adjusted flaps but when this was then further compounded by more issues perhaps had neglected or forgot to retract flaps? Between flaps and trim which would win?

andreas500

https://www.channelnewsasia.com/news...d-jet-11119706

JAKARTA: Indonesia has found the cockpit voice recorder from a Lion Air plane more than two months after the Boeing Co 737 MAX jet crashed into the sea near Jakarta, killing all 189 on board, an official said on Monday.

"It's been found, but we have not received information of the location yet," Haryo Satmiko, deputy chief of Indonesia's transport safety committee (KNKT), said by text message.

Read more at https://www.channelnewsasia.com/news...d-jet-11119706

Hopscotch

It appears they did find the CVR and were able to transcribe audio; unlike NTSB formatting, pertinent transcription is within the main body of the report, rather than an attachment. (1.11.2, pg 79)

http://knkt.dephub.go.id/knkt/ntsc_a...l%20Report.pdf