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Jetstream 31/41 Engines

Sat Jun 30, 2001 11:14 am

Is it standard procedure to pull the prop blades through several revolutions before engine start on the Jetstream 31/41 aircraft? I saw this done today by two crews on their walkarounds today and I am curious. Thanks.
 
T prop
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RE: Jetstream 31/41 Engines

Sat Jun 30, 2001 3:10 pm

Out of an old Garrett TPE331 pilots brief and ops tips booklet:

6.1 Normal Ops procedures checklist
Preflight inspection.

PROPELLER -ROTATE BY HAND

-A valuable practice toward developing a "feel" for characteristic engine sound and rotational resistance; helps to establish a baseline of both feel and noise so that, should a change be detected on future prop rotations, appropriate maintenance investigation can take place.

- If an abnormal resistance is noted, hand rotation should be stopped at the point where the resistance is most obvious; representing 180 degrees displacement of the main rotating group (neutralizing the thermally caused imbalance as cooling continues)

- Rotational freedom should be re-checked after about three minutes of additional cooling (depending on ambient variables).

T prop.

 
JT-8D
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RE: Jetstream 31/41 Engines

Sun Jul 01, 2001 12:22 am

Talked to a pilot a few years back. He said the 331 had a habit of seizing temporarily due to the compressor drive shaft bending slightly after shutdown. After it had completely cooled, it would be fine. Anyone else heard this? My second theory is, maybe he was walking the prop through to clear the oil from the lower cylinders? Yes, Im kidding..JT
 
me
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RE: Jetstream 31/41 Engines

Tue Jul 03, 2001 2:35 am

The pilot you saw spinning the prop by hand was actually twisting up the rubber band for the next flight.

I flew J32's for trans states airlines a few years back. They are, without question, a piece of junk. Sometimes called a "Junkstreem" or a "wetdream". Loud and very cramped for the passengers, unstable for the pilots.
 
AJ
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RE: Jetstream 31/41 Engines

Wed Jul 04, 2001 1:00 pm

Briefly mentioned before, however to expand the TPE-331 suffers from shaft bow if not rotated by hand after shutdown. This is caused by differential cooling between the side of the engine behind the air intake and the other side. On the J31/32 and Metroliner the top of the engine tends to cool quicker, contracting and causing a 'bow' in the shaft. Rotating the engine encourages more even cooling.

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