Definition
The red, green, and white navigation lights mounted on an aircraft to indicate its orientation and direction of travel to other pilots and ground personnel. A red light is on the left wingtip, a green light is on the right wingtip, and a white light is at the tail. Required to be on from sunset to sunrise under FAR 91.209.
Plain English
The colored lights on the wingtips and tail that show others which way the aircraft is pointing and moving, especially at night.
Context Anchor
You will see this term in checklists and procedures for night operations, engine starting, taxiing, and preflight light checks.
Derivation
Called 'position' lights because their fixed colors and locations let an observer work out the aircraft's position and heading relative to them — for example, seeing a red light on your right means another aircraft is moving across your path from right to left.
Why Pilots Care
They prevent mid-air collisions by allowing other aircraft to determine heading and relative position at night.
Intuition Check
Position lights are not lights used to find your own position on a map. They are lights that help other people see the airplane’s position and direction.
Example Sentence 1
Before calling 'clear prop,' the pilot turned on the position lights to alert anyone nearby that the engine was about to start.
Example Sentence 2
From the right side the green position light showed the airplane was heading toward the observer.