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Precision Approach Path Indicator (PAPI) Nighttime Signal Characteristics

This document describes the work performed to determine the useable nighttime range and horizontal coverage of a standard Precision Approach Path Indicator (PAPI) system.

Flight tests were conducted using the Federal Aviation Administration's (FAA) Aero-Commander to fly approaches to the runway 13 PAPI system located at the FAA Technical Center. Distance Measuring Equipment (DME) was used to determine range, and ground tracking was used to determine horizontal coverage.

Results of the flight tests showed a usable range of 8 nautical miles (nmi) and a horizontal coverage of 27° at 4 nmi and 20° at 8(nmi).