Negative autocoarsen on Saab 340

[Dufo]

In case when autocoarsen fails, is it necessary to hold manual feathering pump switch 1) until the prop feathers (few seconds) or 2) until condition lever is placed to fuel off position. I was taught the latter (the prop could presumably unfeather), but cannot find an official AOM/AFM explanation behind method 2.

Thanks :ok:

[B737-pilot]

If memory serves me well, with an engine failure SF340B, things should happen like this:
a) the prop feathers automatically;
if not
b) moving the condition lever to cut off --> prop feathers
if not
c) manual feathering pump switch on

So in my opinion when you use manual feather the condition lever should be in cut off.

We used to do a test of the feathering sistem on the first flight of the day and it was posible to feather an engine running at idle if you weren't paying attention.

[ImbracableCrunk]

From my memory, I agree with B737-pilot



Autocoarsen;
Cut-off
Manual Feather

I'm thinking more CFM than GE these days, but why would you attempt to manual feather before you're in fuel cut-off? You'd use the manual feather if the condition lever didn't work.

[UncleNobby]

Stumbled upon this one a few months later.....!!

The correct procedure for negative auto coarsen is condition lever fuel off. All of the memory items for engine shutdown in the SAAB (where I work) call for condition lever fuel off, then if prop fails to feather select man feather pump on until prop has fully feathered. Auto coarsen is only armed for T/O to 1000 feet and on approach from FAF inbound. Any negative auto coarsen I got in the sim was resolved with condition lever fuel off - never touched the man feather pump.