I confess, Dan, that I assumed pressure from the oil to coarsen the
blades.
In any case, I believe selecting full coarse should be a standard course
of action.
If the engine is windmilling, there will be some residual oil pressure
which can only help.
If the prop fails to coarsen, then at least an attempt has been made to
improve the glide ratio.
Any coarsening of the prop will do so in the event of total power loss.
I note in the Hartzell manual the statement "An operational check of the
governor and the propeller should be made during the run up".
No limitation on the extent of the check is identified in the manual I
have, and I imagine it is up to the individual to choose.
Equally, there appears no warning or advice to the effect that full
governor checks are detrimental, but I'll check the Textron manual to
see if it is mentioned.
My checklist for engine failure, or power loss requiring a forced
landing, includes the requirement to select full coarse on the prop.
The full coarse blade angle is 40.1 degrees, and sure is better than the
speed brake angle of 12.0 degrees. Mind you, not as good as the
Aeroproducts prop on the goose - but what the heck.
Regards
Dom