UAL Bagsmasher From United States of America, joined Sep 1999, 2153 posts, RR: 9 Posted (14 years 5 months 5 days 5 hours ago) and read 4310 times:
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 From United States of America, joined Apr 2001, 1034 posts, RR: 1
Reply 1, posted (14 years 5 months 5 days 1 hour ago) and read 4260 times:
Out of an old Garrett TPE331 pilots brief and ops tips booklet:
6.1 Normal Ops procedures checklist
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).
JT-8D From United States of America, joined Dec 2000, 423 posts, RR: 3
Reply 2, posted (14 years 5 months 4 days 16 hours ago) and read 4242 times:
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 From United States of America, joined Oct 2000, 220 posts, RR: 1
Reply 3, posted (14 years 5 months 2 days 13 hours ago) and read 4224 times:
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 From Australia, joined Nov 1999, 2404 posts, RR: 24
Reply 4, posted (14 years 5 months 1 day 3 hours ago) and read 4206 times:
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.