Beechjet 400 airplane model. The Raytheon Beechjet traces its origins back to the Mitsubishi Diamond 2 bizjet, which Beechcraft acquired the design and production rights to in the mid 1980s.
Beech reengined the Diamond 2 with P&WC JT15D5 turbofans, developed a new interior, and incorporated a number of other minor refinements. Deliveries of the Beechjet began in June 1986, with low rate production continuing until that model was replaced by the Model 400A, which was delivered from November 1990.
The new 400A incorporated a number of improvements over its predecessor. A higher max takeoff weight and greater operating ceiling improved performance, while repositioning the rear fuselage fuel tank increased cabin volume.