Navigation Services

Lighting Systems Group - PAPI

Approach Light Systems (ALS) provide the basic means to transition from instrument flight to visual flight for landing. Operational requirements dictate the sophistication and configuration of the approach light system for a particular runway. PAPI (Precision
Approach Path Indicators) uses light units installed in a single row of four. These systems have an effective visual range of at least 3 miles during the day and up to 20 miles at night. The row of light units is normally installed on the left side of the runway and the glide path indications are as two red and two white (2 red ) when on proper glide path angle of approach. Light combinations indicate when slightly high (3 white ), significantly high (4 white ), slightly low (3 red ) and significantly low (4 red ) so that the pilot may adjust the approach accordingly. PAPI primarily assists by providing visual glide slope guidance in non-precision approaches environment.

FAA Navigation Services Technical Lead:
Donald Lampkins - (202) 267-7332

Current Status: A modification added 114 Tilt-Switch Kits to begin deliveries in June 2005-2006. There are 693 PAPIs in the NAS. Major manufacturers include New Bedford Panoramex (461), Sonicraft (131), AVW (92), and others (9). PAPIs are used to replace Visual Approach Slope Indicator Lights (VASI), and to support Commercial Aviation Safety Team (CAST) and Land and Hold Short Operations (LASHO) new requirements. The FAA is researching replacing incandescent lamps with more efficient Light Emitting Diode (LED) lamps.