Originally Posted by
gums
Salute!
So I would like to review the bidding, huh?
- stick shaker activates as pilot rotates and lifts off. I can see this happening with an abrupt stick input at the normal speed and maybe a bit more AoA than normal. Stick shaker continues. A caution indication or two is displayed, but altitude is insurance, and plane is climbing.
- MCAS, aka "Hal", sees the high AoA, flaps are up, and speed being way less than the mach washout limit, bumps the stab maybe to the max limit for one "bump" and stick forces go up.
- crew feels this and beeps trim with the stick switch.You can see the increased stick force correlating with the MCAS down trim cmd and resulting stab movement. Stab reverses, stick forces go down and the 5 second timer starts. Hal is waiting, and the high AoA is there.
- Hal again cmds stab to move another increment, and crew feels this, as shown on stick forces, then makes manual up trim inputs.
- The plot shows a gradual increase in down trim position of the stab because everytime crew beeps the trim Hal stops, but stab not trimmed all the way back up to original degrees. So the slope of stab position values is slightly negative.
- Hal waits 5 seconds and the process repeats two dozen times until "the event"
- At "the event", control input force from each pilot diverge, Hal continues to trim nose down and crew briefly beeps trim but mainly pulls back harder and harder.
Is that how most here see it?
Gums asks....
Yep, hard to argue it any other way.
It is still hard to understand why they didn't hit the trim cut out switches... The more I think about this, the more obvious that action seems. Trim is running, Control force is getting higher. Manual trim opposite way. Force goes away. Trim runs again. Force goes up. Manual trim. Force less. Rinse and repeat. Hindsight is 20/20, true enough.
Dang it, where is the darned CVR?
- GY