Originally Posted by
Barnsbury
The suggested failure modes still don't fully add up. The fan would have been producing a leisurely five or six tons or so of thrust, which wouldn't have troubled anything compared to the previous take-off loads, so this isn't an overload failure.
It probably happened during a step climb, thus at higher thrust levels.
The total load case is not just thrust, but also torque and centrifugal loads.
I would think that with the lower air density, the rotational speed of the fan will be considerably higher at altitude than at ground level for the same amount of thrust.