[jimmyray]

Yes, the pilots absence is odd. Perhaps he had a heart attack or a stoke?

visible in cockpit at taxi:

not visible prior to crash:

[jimmyray]

Look at this one - Pilot appears to be slumped forward? Also, the trim tab appears completely detached at this point as well.

[Kirkwood]

Don’t these pilots use shoulder harnesses? If so, he couldn’t simply slump forward. That’s why I’m wondering if the seat or seatback broke loose. Also the pilot called mayday over the radio, which seems to suggest an equipment malfunction instead of a major cardiac event or a stroke.