abbreviated precision approach path indicator

abbreviated precision approach path indicator (APAPI)

A precision approach path indicator system consisting of only two light units situated on the left side of the runway. The aircraft is on a slope if the unit nearest the runway shows red and the unit farthest from the runway shows white, too high if both units show white, and too low if both units show red. The APAPI is always set to an eye-to-wheel height (EWH) of 10 ft (3 m).