High Quality Content by WIKIPEDIA articles! The General Electric T58 is an American turboshaft engine developed for helicopter use. First run in 1955, it remained in production until 1984, by which time some 6,300 units had been built. On July 1, 1959, it became the first turbine engine to gain FAA certification for civil helicopter use. The engine was license-built and further developed by de Havilland in the UK as the Gnome, and also manufactured by Alfa Romeo and the IHI Corporation.