I'm doing an electrical load analysis for a field approval I am working on. I've read many posts on many forums alluding to the idea that landing/taxi lights are an "intermittent load" but I can't seem to find an FAA reference to that. Does anyone know where the FAA says that specifically or something contrary.

FWIW, my 185 service manual includes a list of electrical items and there current draw, and there is a separate section labeled "Items not considered part of running load", and in that list are the landing lights. With that in mind, I'm inclined to believe the tribal knowledge. If Cessna did it, it has a shot at being legal, right?

Yes.

FAA's "Airplane Flying Handbook" (Ch. 16, 'Emergency Procedures') actually lists it as intermittent as well. Loads that are not normally activated continuously in all phases of flight are intermittent (night flight, for example). That means position lights, instrument lights, indicators are continuous, while things like starters, landing lights, and flap actuators are intermittent.

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On the other hand, regulations aside, when you're flying through the canyons, best that they be a continuous load, right?

Cary

At one point when we were installing an Odyssey battery in a Husky, I was told by an FAA type that landing lights were a continuous load under FAR Part 23, and the Husky is a 23 airplane.

I don't know whether that's really true or not, and I'm inclined to think it's not, but the point is, you WILL find FAA inspector types who will argue the most conservative line. Find one who'll give you the CORRECT answer, and get him to put it on paper.

MTV

Just as importantly, if the response is negative, ask him/her to show you the reg (politely, just in case he/she is correct ). Inspectors make mistakes, too, just like the rest of us.

Cary