Puritan
Don't know about the Seneca but it is quite possible in cruise flight depending on the airspeed in the case you mentioned for
the RPM to windmill at governed RPM and if the throttle has not been moved from cruise setting the manifold pressure would be the same as before. So you have both engine parameters of RPM and Manifold pressure the same. This would occur as long as the airspeed was high enough for the prop to reach governed RPM before it reached full fine blade angle. In due course as speed decayed as a result of the windmill drag RPM would reduce when full fine blade angle is reached. A good thing to be aware of don't you think?
At take off with lower airspeed windmill force would not be enough to do this in the case of a total failure. In any case Dead foot, dead engine is the PRIMARY way to identify the problem using other indicators only as a confirmation if appropriate.
Can't say that running a fuel tank dry or the like is good practice.
