Plain English Meaning

A long line of bright lights leading up to the runway, with a row of flashing lights that fire one after another like a chasing arrow pointing the pilot toward where to land. It is used at runways that support precision instrument approaches in poor visibility.

Full Definition

A high-intensity approach lighting system installed at the approach end of a precision instrument runway, consisting of steady-burning white lights arranged in a configuration extending outward from the runway threshold, plus a series of high-intensity sequenced flashing lights that fire one after another toward the runway. Two standard versions exist: ALSF-1 (with a tall pole-mounted system and ) and (with red side row bars usable as a Simplified Short Approach Lighting System with when visibility is reduced). are used to support or II .