Initially designed and built by Mitsubishi, it has been further developed and updated by the Beech Aircraft Company, now part of Textron Aviation.

The Hawker 400 is a small, low-winged twin-turbofan aircraft of all metal construction, flown by a crew of two pilots and accommodating eight passengers in a pressurised cabin.

[10] In 1985, Mitsubishi sold the rights and a number of unfinished airframes to Beechcraft, who began manufacturing it as their own model, initially re-designated as the Beechjet 400, certificated by the Federal Aviation Administration in May 1986.

[11] Raytheon/Beechcraft developed improvements for the 1990 400A for longer range, higher take-off weights, luxury appointments and offering an all-glass flight deck.

Beechcraft developed the T-1 Jayhawk version for the United States Air Force, used as a trainer for crew of large aircraft like tankers and strategic transports: 180 were delivered between 1992 and 1997.

In 2003, Raytheon began to produce Hawker 400XP, which included: 200 lb (91 kg) gross weight increase, a nine passenger seating option, thrust reversers, TCAS II, and an emergency locator beacon.

[1] In 2012, Textron has first flown Hawker 400XPR,[17] which improves 4-pax range to 1,950 nmi (3,610 km; 2,240 mi), has better hot and high performance, and can climb to FL450 at max takeoff weight in 19 min.

[1] Data from Brassey's World Aircraft & Systems Directory 1999/2000,[29] Hawker 400XPR Product Analysis[18]General characteristics Performance