2 ms·

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.

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.
      - inferiorhuman 8y ago
        Overspeed is the result of the mistrim No, it wasn't. Overspeed was because the pilots basically firewalled the throttles and never once touched them. Look at the Lion Air flights, they never came close to those sorts of speeds.
        cmurf 8y ago
        If I'm trimmed for level flight and go to 100% power, I will not overspeed. Initial airspeed increases, the plane starts to climb, airspeed decreases, and fairly quickly without any other inputs the airspeed will return to level flight airspeed, but I'll be in a climb. It's basic aerodynmics. Primary flight students are taught this, and in more advanced training it's given a name: positive static stability. All FAR 23 and FAR 25 certified airplanes have this behavior. In the case of ET302, the power settings were completely normal for the phase of flight they were in. What was abnormal was the trim. If the trim were normal, they would have had a normal climb and normal climb speed. On what basis would or should the pilots have made a power reduction? In the case of LNI034 and LNI610, you're determining speed how? Do you have a page reference? Are you even able to estimate percent Vno? What I see for LNI610 is normal takeoff power, and just before midway through the flight a power reduction. Airspeed isn't affected. And how are you comparing the stabilizer trim setting value between LNI610 and ET302?

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.
    - inferiorhuman 8y ago
      Overspeed is the result of the mistrim No, it wasn't. Overspeed was because the pilots basically firewalled the throttles and never once touched them. Look at the Lion Air flights, they never came close to those sorts of speeds.
      - cmurf 8y ago
        If I'm trimmed for level flight and go to 100% power, I will not overspeed. Initial airspeed increases, the plane starts to climb, airspeed decreases, and fairly quickly without any other inputs the airspeed will return to level flight airspeed, but I'll be in a climb. It's basic aerodynmics. Primary flight students are taught this, and in more advanced training it's given a name: positive static stability. All FAR 23 and FAR 25 certified airplanes have this behavior. In the case of ET302, the power settings were completely normal for the phase of flight they were in. What was abnormal was the trim. If the trim were normal, they would have had a normal climb and normal climb speed. On what basis would or should the pilots have made a power reduction? In the case of LNI034 and LNI610, you're determining speed how? Do you have a page reference? Are you even able to estimate percent Vno? What I see for LNI610 is normal takeoff power, and just before midway through the flight a power reduction. Airspeed isn't affected. And how are you comparing the stabilizer trim setting value between LNI610 and ET302?