Effect of Backscatter from Aircraft Beacon Lights on Target Visibility in Fog

摘要

Tests were performed in the fog chamber to determine how the backscatter from aircraft beacon lights (collision-avoidance lights) in a fog of 0.21 per mile transmittance affects an observer's ability to see a set of target lights at a fixed distance equal to the corresponding visual range of 3 miles (approximately 16,000 ft). The tests investigated three white and three red beacon lights, both steady-burning and flashing, with peak intensities from 1200 to 200,000 cp in white and 1200 to 25,000 cp in red. Results from a total of over 10,000 observations, made by 34 observers, show that use of the beacon lights produced no appreciable reduction in target-light visibility except with the highest white-light intensity. There was no apparent difference between the steady-burning and flashing modes of the beacons insofar as target visibility is concerned. (Author)