its territories according to Federal Aviation Administration data, compared to 6730 PAPIs and 623 VASIs. See also Leading lights, similar aid to navigation Pilot controlled lighting (PCL) Precision approach path indicator (PAPI) Runway end identifier lights (REIL) Runway edge lights (HIRL, MIRL, LIRL) Approach lighting system (ALS) Optical landing system References FAA Aeronautical Information Manual, Chapter 2 (Aeronautical Lighting and Other Airport Visual Aids), Section 1 (Airport Lighting Aids) External links FAA Aeronautical Information Manual Airport lighting Optical communications fr:Vasi