Originally Posted by
DaveReidUK
Correct me if I'm wrong, but the coarser the thread pitch (all other things being equal), the more likely a jackscrew is to be back driveable (the spiral ratchet screwdriver principle). Is that what you're saying?
I can't see air loads on the stab being capable of overcoming the combined braking friction in the jackscrew, gearbox and actuator unless we're talking about a previously undisclosed failure in addition to the issues already discussed.
Its MORE than just the pitch ( lead) please take the time to read this simplified explanation
https://www.linearmotiontips.com/how...ll-back-drive/
and for an approximation of loads
https://www.aerospaceonline.com/doc/...actuators-0001