Fatigue as well. Looking at the flight track after the last and final nose down, it's they were overcome. Nose down -> more speed -> more stabilizer nose down f

Fatigue as well. Looking at the flight track after the last and final nose down, it's they were overcome. Nose down -> more speed -> more stabilizer nose down force -> more nose down attitude even without a change in stabilizer -> more speed -> more stabilizer force -> more nose down attitude. And then the ground got in the way.