[kevin]

Jim,

Like a lot of other things in aviation, I guess there is disagreement on this point. I talked to three folks I respect, all AI's with lots of piston experience, and all three told me that there is no need to go all the way into feather, that moving the control enough to detect significant RPM drop is good enough, that if it will move enough to get a 300 to 400 RPM drop, it will feather, and that going all the way into feather is very bad for the engine. To quote one AI: "There is a small chance that if you don't check it every time, the prop may not go all the way to feather, but checking it like that every time makes it much more likely that you will *need* to feather the engine because of engine abuse. The cost to the engine of such a check is not worth the tiny reduction in risk."

The Cessna checklist for both '65 and '78 337s does indeed say to "check feathering to 1200 RPM" from a runup RPM of 1800. I am not completely sure that one should interpret that sentence to mean "put the propellor all the way into feather" (changing blade pitch can be referred to as feathering), but a 600 RPM drop is only 200 RPM more than the 300 to 400 RPM drop I expect when I follow my procedure without going into the feather position.

You have a different opinion than the folks I have gathered information from, and it does seem to be backed up by the text in the manual, as well as your experience.

Guess everyone will have to decide to do what they think is best.

Kevin