This week, we discuss one of the most interesting light jets in the sky, the Hawker/Beechcraft 400, with corporate pilot and aircraft manager Mark Feldman. Mark also tells us about his Boeing Stearman, which you won’t want to miss. Then we talk about WAAS in our new segment Alphabet Soup. Plus, aircraft ownership news, Don’s Tip of the week, and your feedback.
More about the Hawker/Beechjet 400
The aircraft was originally designed in 1977 by Japan’s Mitsubishi, the same company that built the MU-2 turboprop. The new jet was designated the MU-300 with an eye to reassembling it in Texas with Mooney. Mooney went bankrupt and Mitsubishi went it alone at its manufacturing plant in San Angelo, Texas, rebranding the aircraft the Diamond one and getting FAA certification in 1981. The airplane featured a flat floor and a squared oval fuselage that gave passengers more shoulder room and made the 305-cubic-foot cabin seem larger. Overall luggage capacity is 800 pounds. The Diamond featured other innovations not typically seen on light jets of its day: a supercritical wing with a 20-degree sweep to cut drag and increase speed; roll spoilers, which assist with high-speed turns; and anti-skid brakes.
1977 Mitsubishi designed and built two prototypes of a twin-turbofan business aircraft designated the MU-300, the first flying on 29 August 1978. A cantilever low-wing monoplane with a pressurised fuselage and retractable tricycle landing gear, the MU-300 was powered by two JT15D-4 turbofan engines, Mitsubishi Heavy Industries’ MU–300 Diamond has roots dating back to 1969, when the company analyzed the same market Cessna was targeting with its Citation line. Cessna, however, got a huge lead on Mitsubishi when it came time to start pushing airframes out the door—nearly a decade, in fact. Much of the delay was meeting rigorous Part 25 certification rules the FAA had imposed. Diamonds emerged some 500 pounds heavier than target weight. Unlike Cessna, which installed a straight wing on its Citation line at the time, Mitsubishi’s Diamond used a large cabin on a swept wing to differentiate its entrant. Standard accommodation was provided for a crew of two and seven passengers. At the end of the development programme the prototypes were dismantled and shipped to the USA, where they were reassembled by the company's US subsidiary Mitsubishi Aircraft International Inc. Redesignated the Diamond I, the two aircraft were used in the US certification programme, which was granted on 6 November 1981. Initial customer deliveries began in July 1982 and 62 were built. Don was at the Beechcraft airport in Wichita viewing one of the first built in the USA, in the after show. Don has a story about that.
Beech was decidedly behind the power curve and needed to play catch-up. Its solution: buying the Diamond program from Mitsubishi in 1985 and acquiring kits to assemble 64 aircraft. These are known as Beechjet 400s. In 1991, Beech began native manufacturing of the airplanes with a few improvements; these are called 400As. That same year, the Air Force ordered 211 Beechjet 400As to use as trainers for tanker and transport pilots (the 400T or T-1A “Jayhawk”).
In 1983, the manufacturer launched an improved model, the Diamond IA, which featured uprated Pratt & Whitney Canada JT15D-4D engines and first-generation glass-panel avionics. The next iteration, the Diamond II, offered more fuel capacity and still more powerful engines.
The 400A, later rebranded the Hawker 400XP by Hawker-Beechcraft, introduced improvements. These aircraft begin with serial numbers “RK” and range in price on the used market from as little as $700,000 to $2.5 million for a Hawker 400XP from 2010, the last year they were produced. Production of the XP began in 2003, and if you don’t want to invest in a complete makeover, this is the model to buy. It features Rockwell Collins Pro Line 4 avionics and an updated interior.
Similar to its MU–2 stablemate, the Diamond uses nearly full-span flaps to lower approach speeds while utilizing spoilers for roll control. This allowed the Diamond to keep approach reference speeds within a reasonable range, while the swept wing allowed the Diamond to best the Citation II’s high- speed cruise by about 50 knots at a nominal fuel penalty of 13 gallons per hour.
Pilots loved that the Diamond was fast and easy to fly, while passengers raved about the large cabin with a trenchless floor. Comfort is enhanced by a 9.0 psi cabin differential, providing sub-6,000-foot cabin altitudes at typical Diamond cruise altitudes in the mid to upper 30s. It’s certified to FL410.
Beechcraft, which created follow-on designs—the Beechjet 400, 400A, and Hawker 400.
Then called the Beechjet, it falls into the light-jet category: two pilots, up to seven passengers, a range of up to 1,885 nautical miles (with the throttle pulled back; otherwise plan on a little more than 1,400 nautical miles with four passengers) and a top cruise speed of 465 knots. More than 600 have been produced for civilian use. It is currently being remanufactured with many improvements by Nextant Aerospace as the 400XTi and by Beechcraft as the 400XPR
The 400XTi is essentially a Beechjet 400/Hawker 400A/XP with new Fadec-controlled 3,050-pound-thrust Williams International FJ44-3AP engines replacing the original 2,965-pound Pratt & Whitney Canada JT15D-5Rs, aerodynamic improvements to the nacelles and pylons, a new Rockwell Collins Pro Line 21 flight deck, fresh interior and other enhancements. The jets undergo 60 engineering changes, replacement of more than 40 time-controlled components, compliance with A-, B-, C- and D-check inspections as well as compliance with all FAA airworthiness directives and applicable manufacturer service bulletins during a 6,000-man-hour renewal/overhaul process. The resulting remanufactured 400XTi carries a two-year tip-to-tail warranty (three for the engines), which can be extended to five years as an option.
The first remanufactured version was the 400XT, but last year Nextant introduced the 400XTi, with an improved and more spacious composite cabin shell that takes full advantage of unused space in the fuselage, a new noise insulation package, Nextant-designed winglets, Luma Technologies LED warning panels and a Mid-Continent Instruments LCD standby attitude module and True Blue Power MD835 lithium-ion backup battery units. The MD835s eliminate a 90-day inspection interval for the jet’s original lead-acid backup batteries.
An improved version, the Diamond IA, fitted with uprated JT15D-4D engines giving overall performance increases, an EFIS cockpit and with maximum take-off weight increased to 7361kg, was announced in 1983 and the first of 27 built, distin guished by the extra port side window, was delivered in 1984. With an MTOW reduced to 7157kg, but with extra fuel, and more powerful JT15D-5 engines, a further eight aircraft were pro duced as the Diamond II. However, in December 1985, Mitsubishi sold the Diamond II design rights to Beech, together with components for 64 aircraft. These were assembled at Wichita and marketed as the Beechjet 400. Beech then initiated full manufacture of the type and by the beginning of 1991 had received orders for 113 slightly modified Model 400As In February 1990 the US Air Force chose the type as the airframe. element of the Tanker/Transport Training System under the designation Beech 400T T-1A Jayhawk. The USAF requirement is for 211 aircraft and the first of these was delivered in July 1991 and entered service in March 1992, training KC-135, C-5, KC-10 and C-17 crews. Performance-wise, the Diamond IA is good for 420 knots at FL350 to FL370 on about 1,200 pounds per hour. There’s enough fuel for three hours at high-speed cruise or about four hours at long-range cruise.
There is a comparison chart of the deferent models. Buy the remanufactured Nextant Aerospace, as the 400XTi and by Beechcraft as the 400XPR. Just visit our show notes, for the details. And for more history and stories about Don’s involvement in these jets. Don reveals stories of his experiences with these jets, for our patreon subscribers.