|
I am in Colorado and my plane, POH and Maintenance Manual are in Memphis. I'm not a mechanic but here are my assumptions: the feather position "pull up and back" shuts off all oil pressure to the governor and the engine feathers. I don't think it will come out of feather until oil pressure is restored eithe by an accumulator or by turning the engine over in flight (on the ground is a different matter.) The "feather mechanism" as I describe is whatever valve is activated when the prop control is pulled up and back that shuts off the oil. This valve is not activated by simply pulling the prop control back toward feather.
In any event one controls the drop in rpm no matter which of the two ways you check it. I think it may very well be valid to say that unless one feathers the engine on the ground one will never know if all the oil pressure is cutoff.
I am also following the advice of CFIs and AIs is doing what I do. So I guess we are still "to each his own."
Sorry I'm not more of an expert but the proceedure I have been using has been the same on all the twins with prop feather mechanisms for 4+ decades. There is a difference in engines. Some go to feather like the 337 Continentals but some (most, I think) go to low pitch (high rpm) like the Lycomings on an Aztec. That is when oil pressure is removed for whatever reason.
Not much help, am I?
|