Development began in the late 1970s with two Bell 212s being converted into 412 prototypes. An advanced four-blade main rotor with a smaller diameter replaced the 212’s two-blade rotor. A Bell 412 prototype first flew in August 1979. The initial model was certified in January 1981 with deliveries commencing in the same month. The 412 model was followed by the 412SP (Special Performance) version featuring larger fuel capacity, higher takeoff weight and optional seating arrangements. In 1991, the 412HP (High Performance) variant with improved transmission replaced the SP version in production
The current production version, 412EP (Enhanced Performance), is equipped with a dual digital automatic flight control system. In 2013 Bell introduced the 412EPI which includes an electronic (Digital) engine control for a PT6T-9 engine upgrade, and a glass cockpit display system similar to the Bell model 429. Also featured is a Garmin touchscreen navigation system, and the BLR Strake and Fast Fin upgrades for improved hover performance. Over 700 Model 412s (including 260 by AgustaWestland) have been built
An air force, also known in some countries as an aerospace force or air army, is in the broadest sense, the national military branch that primarily conducts aerial warfare.