4 ms·

Autopilot comes up several times in the report, but maybe I'm misunderstanding. Can you clarify? At 05:38:46 and about 200 ft radio altitude, the Master Cautio

Autopilot comes up several times in the report, but maybe I'm misunderstanding. Can you clarify? At 05:38:46 and about 200 ft radio altitude, the Master Caution parameter changed state. The First Officer called out Master Caution Anti-Ice on CVR. Four seconds later, the recorded Left AOA Heat parameter changed state. At 05:38:58 and about 400 ft radio altitude, the flight director pitch mode changed to VNAV SPEED and Captain called out “Command” (standard call out for autopilot engagement) and an autopilot warning is recorded. At 05:39:00, Captain called out “Command”. At 05:39:01 and about 630 ft radio altitude, a second autopilot warning is recorded At 05:39:22 and about 1,000 feet the left autopilot (AP) was engaged (it disengaged about 33 seconds later), the flaps were retracted and the pitch trim position decreased to 4.6 units. Six seconds after the autopilot engagement, there were small amplitude roll oscillations accompanied by lateral acceleration, rudder oscillations and slight heading changes. These oscillations continued also after the autopilot was disengaged. At 05:39:55, Autopilot disengaged, At 05:39:57, the Captain advised again the First-Officer to request to maintain runway heading and that they are having flight control problems. At 05:40:00 shortly after the autopilot disengaged, the FDR recorded an automatic aircraft nose down (AND) activated for 9.0 seconds and pitch trim moved from 4.60 to 2.1 units. The climb was arrested and the aircraft descended slightly.

Someone1234 8y ago
Before MCAS started malfunctioning. Autopilot was enabled for a short period after take-off, then disabled at 05:39:55 due to turbulence and never re-enabled. If you look at the graph in Appendix 1/page 26 -- FDR Data you'll see that the first MCAS command occurred at 05:39:30. Once autopilot was disabled it remained disabled until impact. The information you're quoting above is just included for informational reasons, it likely won't play a part in what caused this accident.
- inferiorhuman 8y ago
  And if you look further through the transcripts you'll see that they kept playing with the flight director for reasons unknown.
  - UnoriginalGuy 8y ago
    That's commentary. We can reasonably speculate they were looking at warnings and the flight log, autopilot is only one part of the flight director and as autopilot was never turned back on, pointing at it seems odd.
    - inferiorhuman 8y ago
      That's commentary. Changing settings in the flight director is very much an action (not mere commentary). Plus it's a good distraction from flying the plane — especially while the overspeed alarm is going off.
      - orwin 8y ago
        Maybe, just maybe, when you're in a plane that does not respond to your commands, you want to have a look at the most likely possibility: the autopilot did not disengage, or the autopilot malfunctionned and prevents you to get full control of the airplane. IF hte pilots knew about MCAS, they would likely have checked that instead, but they did not. Most pilots are rationnal and pretty smart people. Implying that two of them are stupid enough to "play" with the autopilot in this situation is pretty insulting. This kind of reactions are interesting though. I might tour facebook, twitter and reddit to see if it's widespread.
      - cmurf 8y ago
        Overspeed is the result of the mistrim. They were in fact flying the plane, the significant back pressure they used to fight the mistrim makes that clear. On what basis do they anticipate 4 seconds after two successful nose up trim using yoke toggle switches (manually initiated, electric motor turns jackscrew) that MCAS will cause a 40 degree nose down within seconds? Nothing. There's no basis for expecting such madness. The emergency AD following LNI610 doesn't at all account for significant mistrim, the possibility of heavy jackscrew loading forces that could prevent manual (handcrank) retrim, and the necessity of setting stab trim switches back to normal to solve the mistrim. It's realy vile to me that this whole mistrim scenario was not thoroughly explored by the FAA and NTSB (independently of each other) in 737 MAX capable simulators following Lion Air 610. Very clearly the emergency AD was still inadequate months after Lion Air 610. Could ET302 have been prevented? Perhaps, but not based on the then published AD.

Someone1234 8y ago

Before MCAS started malfunctioning. Autopilot was enabled for a short period after take-off, then disabled at 05:39:55 due to turbulence and never re-enabled. If you look at the graph in Appendix 1/page 26 -- FDR Data you'll see that the first MCAS command occurred at 05:39:30. Once autopilot was disabled it remained disabled until impact. The information you're quoting above is just included for informational reasons, it likely won't play a part in what caused this accident.

inferiorhuman 8y ago
And if you look further through the transcripts you'll see that they kept playing with the flight director for reasons unknown.
- UnoriginalGuy 8y ago
  That's commentary. We can reasonably speculate they were looking at warnings and the flight log, autopilot is only one part of the flight director and as autopilot was never turned back on, pointing at it seems odd.
  - inferiorhuman 8y ago
    That's commentary. Changing settings in the flight director is very much an action (not mere commentary). Plus it's a good distraction from flying the plane — especially while the overspeed alarm is going off.
    - orwin 8y ago
      Maybe, just maybe, when you're in a plane that does not respond to your commands, you want to have a look at the most likely possibility: the autopilot did not disengage, or the autopilot malfunctionned and prevents you to get full control of the airplane. IF hte pilots knew about MCAS, they would likely have checked that instead, but they did not. Most pilots are rationnal and pretty smart people. Implying that two of them are stupid enough to "play" with the autopilot in this situation is pretty insulting. This kind of reactions are interesting though. I might tour facebook, twitter and reddit to see if it's widespread.
    - cmurf 8y ago
      Overspeed is the result of the mistrim. They were in fact flying the plane, the significant back pressure they used to fight the mistrim makes that clear. On what basis do they anticipate 4 seconds after two successful nose up trim using yoke toggle switches (manually initiated, electric motor turns jackscrew) that MCAS will cause a 40 degree nose down within seconds? Nothing. There's no basis for expecting such madness. The emergency AD following LNI610 doesn't at all account for significant mistrim, the possibility of heavy jackscrew loading forces that could prevent manual (handcrank) retrim, and the necessity of setting stab trim switches back to normal to solve the mistrim. It's realy vile to me that this whole mistrim scenario was not thoroughly explored by the FAA and NTSB (independently of each other) in 737 MAX capable simulators following Lion Air 610. Very clearly the emergency AD was still inadequate months after Lion Air 610. Could ET302 have been prevented? Perhaps, but not based on the then published AD.