Originally Posted by
sotiras
Essentially this is an AFCS malfunction whereby the software receives no signal from the collective jack as to what position it is in. So the software goes looking for it, and demands inputs of huge magnitude at a very swift rate. It is absolute mayhem in the cockpit ( Been there!) as the collective hydraulic jack goes from maximum to minimum unpteen times per second.
Originally Posted by
awblain
The kinetic energy of the rotor is also not large compared with the power flowing through it. A 200-kg rotor, 10-m in diameter has something like 2MJ of energy at 200rpm (~20 radians/s). But, it's driven by about a MW of power, so in the right/wrong conditions, it could stop in a few seconds.
Thanks for this. Also, there must be
some amount of pitch in order to bring Nr to zero.
Based on awblain's explanation,
rapid loss of Nr is possible if power is absent meaning that in order to achieve the AAIB's initial findings of a high speed impact with nil apparent Nr we are looking at a total power failure followed by sustained pitch on the main rotor?
