Piston props (that i have flown) don't feather during shutdown...

It's tough to diagnose a problem on a complex system like a feathering, prop
without being hands on, and without knowing the details of the feathering
mechanism of the model of prop involved, but my initial inclination is
still that it is governor or hub, not engine.... Since then I took a quick
look at the commanche prop hub, and they have a pair of locks that prevent
the blades from feathering when the rpm is below a certain rpm... Those
locks are stuck open or damaged... However, the blades still wouldn't
feather as long as the engine has enough oil pressure for the piston to
overcome the feathering spring... Since he specifically said he had oil
pressure at idle I still am very suspicious that the prop governor has an
internal leak after it gets hot...

Denny


Actually, it may just be a bad idle mixture setting. My engine when hot
used
to stall at idle (frequently rolling out with the throttle at idle). I
didn't have a twin,
but I can imagine that the prop would feather during such a sequence in a
twin.