The Chetak (Alouette III) is an enlarged development of the Alouette II series, and was Aerospatiale’s most successful helicopter in terms of numbers built until the mid 1980s. The initial SE-3160 Alouette III remained in production for almost a decade until 1969, when it was replaced by the improved SA-316B with strengthened transmission and a greater maximum takeoff weight. This version received FAA Type Approval on 25 March 1971.Further development led to the SA-319 Alouette III Astazou, The SA-319 entered production in 1968 as the SA-319B. The sale of Alouette III to India included licence agreements for manufacture of the aircraft in the country. Hindustan (HAL) of India continues to licence build Alouette IIIs as the Chetak (first as SE-3160, later as SA-316B). The Chetak continues to be in service with the Army. It is used in a broad spectrum of roles ranging from winching operations, cargo operations, under slung cargo operations, Casualty evacuation, parachute jumps, formation flying and communication sortie.