Definition
A row of sequenced flashing white lights installed on the extended centerline of a runway approach, leading inbound toward the runway threshold. RAIL is a component of certain approach lighting systems (notably ALSF and MALSR) and provides strong visual guidance to help the pilot align the aircraft with the runway during the final stages of an instrument approach.
Plain English
A line of strobe lights that flash one after the other along the approach to a runway, pointing the way to the start of the runway like a moving arrow.
Context Anchor
Seen in instrument approach information and in discussions of runway lighting or inoperative approach lighting components.
Why Pilots Care
Knowing the status of RAIL helps determine if an approach can be continued or if minimums must be adjusted due to missing visual cues.
Intuition Check
RAIL does not mean a physical rail or track on the ground. In this context, it means a set of flashing lights that visually guide runway alignment.
Example Sentence 1
Breaking out of the clouds on the ILS, the pilot picked up the sequenced flashes of the RAIL and easily aligned the aircraft with the runway centerline.
Example Sentence 2
With the RAIL inoperative, the pilot elected to fly the approach with increased landing minimums.