Dan Thompson wrote:
Lyc and TCM require it based on possible damage to the engine from a
sudden stoppage. This has never made sense to me from an engineering
standpoint. When the engine is started it goes from barely turning to
suddenly spinning fast. Why can't it take a faster than normal
deceleration from a prop flailing against pavement or bashing a tow
bar?

I can see how the impulse decelleration of a strike vastly exceeds that of
normal engine operation.

I could see the crank "twisting" especially if it were pressed together from
separate parts (I have no idea if it is). I'd be interested to know what %
of teardowns after prop strikes actually uncover hidden damage, and what
damage that was.