AIM 4-3-23 (f) says "all exterior lights should be illuminated when taxiing on or across any runway". AC 120-74B 7.h.2.c has similar words, except that it's limited to "crossing a runway". Both conflict with other guidance, which would imply that turning on the landing light is a signal of your intent to take off. Seems that it should be "all exterior lights except landing lights". How do the pros interpret this?


1 Answer 1


This is discussed in this question: Should landing light be off during line up and wait position?

When crossing a runway, you do use landing lights along with everything else, and since you're on a taxiway, the presence of the landing lights in this case isn't understood as intent to takeoff since you aren't lined up on a runway.

For an aircraft that is at the end of the runway, lined up & in a position to take off, that's when the idea of "landing lights on = intent to take off" applies. When on-to-hold, everything else is on, mainly to make the aircraft visible in a "please don't land on me" sort of way, but the landing lights off provides an assurance to Tower controllers & anybody who is crossing the runway down-field that you really are planning to remain stationary right now. Then, with takeoff clearance, the landing lights come on. And if I thought that I'd been cleared to cross the runway but the other aircraft (lined up) has landing lights on, I have an earlier cue that he is powering up, so I'll hold short & ask the controller what's up. Matters not if he was wrong, I was wrong, or controllers were wrong; we're all better off if the taxiing aircraft doesn't enter the runway ahead of somebody accelerating toward takeoff speed, and the concept of "landing lights on = intent to takeoff" helps there.

And, conversely, if I'm starting to advance power for takeoff & somebody with all lights on seems to be rolling toward "my" runway, all those lights (A) helps me see him all the better, and (B) gives me a cue as to his intentions. So I might reconsider continuing the takeoff until things get resolved.

Conflicts like that are (thankfully) quite rare, but because the consequences are so grave, keeping everybody aware of everybody else's intentions is a really good thing.


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