PT6 question

[MLenoch]

Why do we pull the props back to feather prior to shutting down? I cannot see
any reason for this. This seems a useless procedure on the shutdown checklist.

If the prop levers are left forward upon shutdown, the prop blades will go into
feather when oil pressure drops off. On start up, the props will unfeather
with the same spool up as if the check list was followed.
Thx in advance,
VL

[B25flyer]

>Why do we pull the props back to feather prior to shutting down? I cannot
>see
>any reason for this. This seems a useless procedure on the shutdown
>checklist.

This is going back a few years, like 30
+, to my Beech 99 ground school. The P&W engines have always been 'free
turbine" compared to the Garrett TPE series that are direct connect or bigger
stuff like the Allison T-56/501D22. It has something to do with engine oil
scavange I think. Another part is that the engines can idle at lower rpm with
feathered props. Also the newer P&W 100 series have prop brakes so the engines
on the ATR and DASH eight can be running as APU's.

Any more I just sell them not fly them.
I am sure someone will prove me wrong.

Walt

[Matthew Waugh]

There is no lubrication to the prop once the engine shuts down. It's a free
turbine so the front end (back in most PT6 turbo prop installations) can be
long shutdown while the prop would be merrily spinning.

Mat

--
Matthew Waugh
Comm. SEL MEL, CFI-AI
http://home.nc.rr.com/mwaugh/learn2fly/index.htm

"MLenoch" > wrote in message
...
> Why do we pull the props back to feather prior to shutting down? I cannot
see
> any reason for this. This seems a useless procedure on the shutdown
checklist.
>
> If the prop levers are left forward upon shutdown, the prop blades will go
into
> feather when oil pressure drops off. On start up, the props will
unfeather
> with the same spool up as if the check list was followed.
> Thx in advance,
> VL