The Bell 412 uses a four-blade main rotor. The first prototype first flew in August 1979. The initial model was certified in January 1981. 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 412EP (Enhanced Performance) version is equipped with a dual digital automatic flight control system.