EI grounding check

[ronrapp]

I recently purchased an RV-6 equipped with one Pmag and one Lightspeed Plasma III. This is my first aircraft with electronic ignition.

When I learned how to fly on a magneto equipped aircraft, I was taught to briefly turn off the ignition prior to shutdown to ensure the mags were grounded properly and I didn’t have a “hot” magneto when the switches were off.

Two questions: Is this grounding check useful with electronic ignition? Will performing this check harm the system in any way?

Thanks,

—Ron

 

[Carl Froehlich]

SNIP

Two questions: Is this grounding check useful with electronic ignition? Will performing this check harm the system in any way?

Thanks,

—Ron

Yes - Just like mags you do the same igntion check each time.
No - Will not harm the system.

Note: With your setup you will need to interprete what the mag drop is as it will not be the same as with standard mags. Here:
- Turning off the pMag you will see a very small drop in RPM
- Turning off the Lightspeed you will see a larger drop in RPM
- From time to time verify the pMag internal gererator is functioning by opening the pMag breaker as part of the check. There should be not change in the engine.

The reason for this is the pMag timing is retarded more that the Lightspeed at the typical mag check RPM. Here the real indication of ignition health is verifying EGT rise when you turn off one ignition.

Carl

 

[ronrapp]

Thanks for the detailed reply, Carl! I know some people wire in a momentary switch to cut out the PMag for that check, but on my aircraft it simply is wired to a Klixon CB, so I only do that check occasionally so as to not wear out the breaker.

--Ron