A little back story first: I have dual P-mags, am one of the principles with
EICommander, and have my P-mags wired so that I can force them to run off of their internal power due to a three way switch I have installed on each P-mag.
A few weeks back I was running some errands with the -9 and during the last run-up, my engine just died when performing the run-up while forcing the left P-mag to run off of internal power.
The P-mag ran just fine off of ship's power (same as an early E-mag) and the other P-mag's internal generator worked fine. The ignition was operating normally and EICommander never picked up any anomalies. The only way I knew there was a problem was because I could turn off ship's power during the run-up.
Both P-mags were removed and when turning the shaft on the left one you could hear some light grinding noise and it was slightly harder to turn then the functioning right P-mag. Total time on both P-mags was 500.9 hours.
Both P-mags were shipped back to E-mag Ignitions and they were returned four days later. I told E-mag I was in no hurry, so no rush. The defective P-mag was repaired, the functioning one was inspected, and both were cleaned prior to their return.
Total cost of the repair was $38.00.
Why did this P-mag fail? I have no idea but these P-mags were in the old engine when I had a catastrophic prop strike. They were sent back for inspection at that time and nothing unusual was noted at that time.
Searching this forum, I only found one other instance of a similar problem.
Lessons learned for all of you running P-mags:
1. Turn off power to your P-mags prior to flight to verify the internal generator is functioning properly.
2. Every condition inspection, remove your P-mags and inspect them. The inspection should seeing of the shaft wiggles or grinds when turned.
P-mag run-up and yearly inspection
Linear Mode
