I think the practice of straining the crankshaft by cycling the prop multiple times is a throwback to DC-3 days when the governor design was different. Engine manuals usually only suggest one cycle. The feather gate check is at lower RPM so may be less stressful?
Rwy20 wrote:
On planes with full engine instruments (i.e. 6 EGT probes), I am looking for an EGT rise from each cylinder when switching to each mag. For this, I bring up the RPM to whatever is written in the POH for the run-up, normalize the EGTs on the engine monitor and wait they’re fairly stable (maybe normalize again), switch to one mag, look for 6 EGTs rising, switch back to both, look for EGTs falling, and switch to the other mag and look for 6 EGTs rising again. This is definitely longer than a few seconds. But I would be interested to hear if there is a quicker way to do this check.
I do exactly the same and it doesn’t take more than perhaps 10 seconds. By the way the POH doesn’t call for this, so if you thought prudent (i.e. risk of stone chipping), you should weigh up each risk against the other. I’d prefer to skip checking EGT rise, as any faults there usually show up either in rough running, or a mag drop out of tolerance.
AnthonyQ wrote:
how many cycles of the prop are really necessary?
My POH says one time normally, but 3 times if cold. I believe it’s about getting warm oil flushed through the governor. May be totally dependant on what governor is fitted. In other words, follow the POH/manufacturers engine documentation.
