The Hawker 400XP is basically the same as the Beechjet 400A, with some minor changes. The Raytheon Beechjet 400/400A evolved from the Mitsubishi Diamond 2 design that was bought by Beech in the mid-1980s.
The original Mitsubishi MU300 Diamond 1 flew for the first time in August 1978. In 1986, the Diamond 2 replaced the Diamond 1; however, only 11 Diamond 2s were built before Beech purchased the design and production rights. The Diamond 2 was renamed the Beechjet 400 and equipped with JT15D5 turbofan engines, a new interior, and other minor changes.
The new Beechjet 400A has a higher maximum takeoff weight and greater operating ceiling along with improved performance. Moving the rear fuselage fuel tank increased cabin volume. The flight deck features a Collins Pro Line 4 electronic flight instrument system avionics suite.
Raytheon renamed the Beechjet 400A in 1996 and it was replaced by the Hawker 400 XP in 2003.
