a unique anti - icing management system for a gas turbine engine is disclosed according to which , at all times , only the required amount of heat is applied to inlet surfaces of the engine to prevent the formation of ice . heated air is bled from the compressor discharge for this purpose and the amount of flow of the heated air is adjusted by a uniquely operated solenoid valve under the direction of an electronic control responsive to any one of a variety of meaningful conditions including , but not necessarily limited to , temperature of an anti - iced surface at the inlet to the engine , rotational speed of the engine , and the presence of an ice producing meteorological condition . the solenoid valve assumes only two operable positions , namely , a fully open position and a fully closed position , and is operated in a pulsed fashion to control flow on a time basis , rather than on a percentage - of - opening basis which is the conventional mode of operation . a switching operation or mechanism within the electronic control , such as a microprocessor , is responsive to any of the aforementioned conditions to cause the solenoid valve to pulsate according to a predetermined pattern which assures a minimally sufficient flow rate of heated air to the regions to be heated .