Hawker 400

The Hawker 400 (also known as the Beechjet 400) is a light business jet. Initially designed and built by Mitsubishi, it has been further developed and updated by the Beech Aircraft Company, now part of Textron Aviation.
It was produced over 30 years under the names such as "Mitsubishi Diamond/Diamond II", "Beechjet 400/400A", and "Hawker 400XP"; military version "T-1 Jayhawk" was also produced. In total, over 900 Hawker 400s have been delivered. 
Since 2017, a factory-engineered and supported upgrade to Hawker 400XPR is provided, reducing fuel consumption by 16-20%, and improving range by as much as 33%.
Design.
It 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. Its wings use a computer designed, supercritical airfoil in order to minimise drag. Its two Pratt & Whitney Canada JT15D turbofans are mounted on the rear fuselage.
Powered by JT15D-5/-5R, it can fly with four passengers, cruising at Mach 0.71–0.73, and most pilots are comfortable flying it over three hours, about cruising at Mach 0.73–0.76, typical missions are 1.5 to 2.0 hours with block speeds.
It burns of fuel the first hour, dropping to for the second.
Basic operating weights range from , full tanks payload is less than with an average passenger load of three, however its full capacity is six passengers 
Development.
The aircraft was originally designed as the Mitsubishi MU-300 Diamond, an all-new, all-jet development to complement and slot above the Mitsubishi MU-2 and provide Mitsubishi Heavy Industries with their top-of-the-line corporate aircraft model (hence the name "Diamond"). It first flew on August 29, 1978. Mitsubishi went on to produce 97 MU-300s, all of which were assembled by the company's United States subsidiary.
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.
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. The Japan Air Self-Defense Force 400T trainer shares the T1-A Type certificate.
In 1993, Raytheon purchased the Hawker business jets from British Aerospace and renamed the Beechjet 400 as the Hawker 400 to include it in the line. 
In 2003, Raytheon began to produce Hawker 400XP, which included: gross weight increase, a nine passenger seating option, thrust reversers, TCAS II, and an emergency locator beacon. 
In 2008, Hawker Beechcraft announced an improved Hawker 450XP including new, more fuel efficient Pratt & Whitney PW535Ds with 2,965 pounds of thrust each, but it was canceled in June 2009 due to poor economic conditions.
Nextant Aerospace re-manufactured Hawker 400XP as the Nextant 400XT, replacing the JT15Ds with Williams FJ44-3APs and adding new avionics and interior. It was FAA-certified in October 2011.
Up to one-third of the 400A/400XP fleet could be retrofitted, enabling improved range, speed and fuel efficiency. It should keep their resale value to remain in economic service for another twenty to thirty years, like Falcon 20s reengined with TFE731s.
In 2012, Textron has first flown Hawker 400XPR, which improves 4-pax range to , has better hot and high performance, and can climb to FL450 at max takeoff weight in 19 min. The conversion features new avionics, interior, winglets, and Williams FJ44-4A-32 engines. Hawker 400XPR was certified in 2016, and first fully configured Hawker 400XPR was delivered in July 2017; the upgrade can be performed in 12 weeks with a choice of Rockwell Collins Pro Line 4 to 21 or Garmin G5000 avionics.
Operational history.
The type is used by many corporate and private users, it is also used by air-taxi and air charter companies.
In 2014, most were U.S. registered, a majority with single aircraft operators.
Flight Options and Travel management co. were its largest operators as NetJets Europe has disposed of its fleet.
The second highest concentration was in Mexico, then Brazil, the rest were scattered throughout the world.
The USAF operated 178 T-1A Jayhawks.
Charter and fractional operators fly at least 800 to 900 hours per year while most corporate operators fly 300 to 400 hours.