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by jcutrell 1219 days ago
Generally spatial disorientation would be pretty unlikely this close to departure, since the departure path tends to be “straight forward with a climb gradient of X” - a pretty unusual situation for pilots of that level of experience.

A possible scenario that has been discussed before is the engagement of autopilot (which often happens at this phase of flight post-departure) with an incorrect altitude entered - my guess is something like 310 rather than 31000, particularly because the language used for altitudes above 17k is in flight levels - “cleared Flight Level 310”, autopilot engages, “whoops…” disengage, recover, climb and continue with corrected autopilot setting.

Again, still odd, but very experienced humans make mistakes like this pretty regularly.

4 comments

Ceilings were 800 feet, so they were in the clouds almost immediately after departure. The weather in the area that day was terrible and extremely turbulent. I think you drastically underestimate how powerful spacial disorientation is. Given the passengers lost all visual cues just after taking off, and there was likely at least moderate turbulence on climb out, the passengers probably just felt like it was a bumpy climb out. The human body doesn't register progressive falling very well without visual cues.
That amount of freefall would absolutely register. Falling is one thing - being weightless for a few seconds is absolutely noticeable.
Not an expert here, but isn't this far beyond the descent rate that autopilot would employ in normal operations?
I am also confused about the "spatial disorientation" argument, I'm not a pilot but I know there's a good reason there's a primary flight display with an abundance of information(including vertical speed, indicated airspeed and pitch) on the 777 which should've given pilots enough indication about what's going on.
> A possible scenario that has been discussed before is the engagement of autopilot (which often happens at this phase of flight post-departure) with an incorrect altitude entered - my guess is something like 310 rather than 31000

This sounds the most plausible to me of what I’ve heard. Would also explain why “further training” was ordered.