Auto Relight

[seanmcgillivray]

I have the auto relight kit installed on my TC. Anyone care to share best practices? I can see turning on the igniters below 5k if in visible moisture.

Any advice would be appreciated.

[Bruce Byerly]

Sean - it saves you from having to turn the ignitors on. Or, preferably, as insurance if you forget in worst case scenario. In my experience I’ve only heard of a flameout with a bunch of slush on the runway on rollout directly ingested or possibly some significant ice ingestion. YMMV.  I operate them all the same. Just my opinion.

[donv]

When are they supposed to come on?

I use my ignition a lot, a habit which I picked up in the air ambulance days at Aero Air. I run them for every takeoff and landing, and when I have ice adhering to the spinners. With the auto ignition, I might just rely on the auto feature, though, and save on the igniter plugs.

[Bruce Byerly]

I am looking for the flight manual supplement but I believe it’s negative TQ and I kinda don’t want to wait for that 

[seanmcgillivray]

Bruce, you are correct on negative torque. If the RPM drops below 60% the ignitors will fire.

My thought is it would save me from long periods of time of firing the ignitors when I am in the soup and not in a critical phase of flight.

Take off (IMC) and below 5k (IMC) I might just go to manual.

[donv]

Ignitors are not that expensive... personally, I don't worry about it that much. I run them when there is more than a trace of ice on the airplane, so not any time I'm in IMC, or even any time I have the inlet heat on. Particularly, I am concerned with ice on the spinners, and particularly when descending or flying into warmer air where it will melt and fly off.

Based on your description of the auto system, I'm not sure I would operate any differently.

[Adam Frisch]

My old igniter switch is spring loaded, so you can't keep it engaged without taking your hands off the switches. Nor were they originally rated to be run continuously. I've since changed to continuous igniter boxes, but the switch is still the old one. Might be one of those switches that mysteriously has the spring taken out by an unknown saboteur...

[Bruce Byerly]

Bruce, you are correct on negative torque. If the RPM drops below 60% the ignitors will fire.

My thought is it would save me from long periods of time of firing the ignitors when I am in the soup and not in a critical phase of flight.

Take off (IMC) and below 5k (IMC) I might just go to manual.

I knew there was a reason I didn’t count on that system Sean. Nice to have, don’t get me wrong, but I don’t want to wait for a spool down to add ignition. I don’t use ignitors unless it’s real potential icing or some significant rain or contaminated runway. This message is not FAA approved.