Originally Posted by
awair
Obviously, if we’re talking about GA aircraft that have a full power down after flight, this wouldn’t apply.
But can.
At all the GA flight schools/rental FBOs I encountered, the SOP (at any time of day) was: nav lights on if the battery was on. To indicate to the outside world, "This aircraft is occupied and 'hot,' and engine start and movement
may be imminent."
Progressing to: beacon(s) - "engine starting right now!" and optionally, taxi light(s) - "movement starting right now!"
And yes, we also flew with the nav lights on, even in daylight. Every little bit helps others "see and avoid." Now it's just habit.
I figure the regs are usually just the bare minimum, and it doesn't hurt to over-deliver (except for the really bright lights - strobes and landing lights).