Intensity Control of Flashers

This report describes tests and experimentation with intensity control of condenser discharge lights (flashers) with a three-step intensity control, and used in a Runway Alignment Indicator Light (RAIL) System as part of a Medium Intensity Approach Light System with sequenced flashers (MALSR) during both day and night and over a wide range of visibility conditions. Also, test and experimentation were conducted with a voltage sensing circuit intended to operate the intensity controlled MALSR from the Control Tower using current changes in the runway lighting circuit. Two intensity controlled MALSR systems; one, 2,400 feet long on Runway 4, and another, 3,000 feet long on Runway 13 were flight tested during the evaluation. The results of the evaluation tests indicated the following: (1) the voltage sensing circuit using current changes in the runway lighting circuit provided satisfactory operation of the MALSR from the Control Tower, (2) the intensity controlled MALSR operated satisfactorily and adequately supported flight operations during both day and night and over a wide range of visibility conditions, (3) compatible intensity levels between the MALSR and the runway lights were obtained to provide a satisfactory intensity balance for flight operations during the weather conditions flown, and (4) the operation of condenser discharge lights during night VFR and IFR conditions were not distracting and did not subject pilots to annoying glare.

Authors: Bernard Weinstein