The APAPI optical system assembly with LED light sources and its visibility in inhomogeneous atmosphere

The PAPI optical system with incandescent light sources (halogen airport lamps) is already an integral part of the airport lighting system (ALS), both stationary and mobile airfields the Czech Air Force. Development unambiguously directs to replacement of the incandescent light sources in the APAPI optical unit with LED light source with high luminous efficacy. Considerable technological and light differences among the LED light sources and the halogen airport lamps lead to high difficulties of the theoretical design, development and construction of the new LED APAPI optical system assembly. This article illustrates the shape, light efficiency and spectral characteristics, differences among the LED light sources and the halogen airport lamps and possible way of APAPI optical system design with LED light sources. Farther the article determines the APAPI visibility range in the inhomogeneous atmosphere by computer support.