Operational Dissipation of Supercooled Fog Using Liquid Propane

Abstract

This paper describes the equipment, the theory, and the results of an operational fog-dissipation system installed at Fairchild AFB, Washington, during the winter of 1969?70. An array of stationary ground dispensers was employed to determine the effectiveness of such a system for providing operational support to aircraft landings and take-offs. Usable clearings followed 25 of 29 seeding operations conducted to bring field conditions above minima. In 17 cases the clearings were conclusively the result of fog seeding. Natural clearing appeared to be at least partially responsible in the eight other cases. Seeding failed to produce usable results in four cases in which the temperature was 31F or higher. In an additional five cases preventive seeding was carried out when initial conditions were above minima. In these cases no attempt was made to evaluate the results due to the uncertainty in knowing the conditions which would have occurred without seeding. A total of 68 aircraft departures and 35 landings were made possible during the project.