Investigation of Field Encountered Precision Approach Path Indicator (PAPI) System Problems

The purpose of this investigative effort was to determine the cause for, and extent of, field encountered problems with. installed Precision Approach Path Indicator (PAPI) systems. The Visual Guidance Section at the FAA Technical Center was tasked with flight testing field installed PAPI systems, on a random basis, to determine whether the problem, low visual glidepath signals at the Austin Minnesota Municipal. Airport, might exist at other airports. As a result of the flight testing activity, similar problems were discovered at other locations. Subsequent investigation revealed: that the problems were basically due to inadequate quality control and inspection procedures at manufacturer's production facilities. Factory inspection visits were accomplished to uncover the source of production deficiencies, and remedial measures are being taken by the manufacturers to eliminate the problem.

Author: Thomas H. Paprocki