The Diamond D-JET is a composite, five-seat, single-engine very light jet developed by Austrian aircraft manufacturer Diamond Aircraft Industries. The intended cost for the aircraft was advertised by the company as being US$1.89 million dollars in March 2009. Development of the D-JET has been disrupted by funding shortfalls during the Great Recession. By February 2013, the development program had been suspended pending company reorganization, which included the workforce related to the D-JET being laid off. During May 2014, Diamond confirmed the continued suspension of the programme, but stated that it had not been cancelled. During December 2016, a majority share of Diamond Aircraft Canada was sold to Chinese firm Wanfeng Aviation; reportedly, this shall result in a detailed re-assessment of the D-JET program, including options for the potential resumption of its development. The Diamond D-JET is a very light jet aircraft, seating up to five personnel and powered by a single engine. A key attribute of the design was its high level of stability during flight, which was reportedly present through its full envelope even during challenging manoeuvres. As a result of its clean exterior design, the D-JET possesses relatively low drag, enabling the aircraft to glide in excess of 65 miles from its 25,000-foot ceiling altitude. The cabin of the D-JET was intended to feature various design elements to enhance onboard comfort, such as the proposed seating layout and the low vibration levels present during flight, for both passengers and crew. The center cockpit pedestal is cantilevered to ease entrance and egress in comparison to some competitors. Separated baggage compartments are located within the interior of the aircraft's nose and to the aft of the main cabin, both of which being externally accessed. The D-JET is powered by a single Williams FJ33-4A turbofan engine, which is equipped with an electronically controlled full-authority digital engine control (FADEC) system. Various functions, such as engine startup and over-speed selection prevention, have been automated and are seamlessly performed by the FADEC system. For redundancy, the dual-channel FADEC system uses four independent electrical power sources in addition to battery backup. Diamond opted to adopt a centerline location for the engine, air for which is fed through inlets embedded into the wing roots. The central location of the engine places makes it close to the center of gravity of the D-JET, reducing pitch forces, however, there are some drawbacks to this approach, including elevated air losses within the ducting arrangement used and a greater likelihood of foreign object ingestion. According to aviation publication Flying Magazine, the controls of D-Jet "feel completely natural...stability is excellent, and I found the workload to be very low". Akin to most jet aircraft, possessing a wide range between minimum and maximum airspeeds, the D-Jet has a larger pitch trim range than a piston-engined counterpart, thus use of the trim control through the takeoff and landing procedures is necessitated to a greater degree than propeller-driven aircraft. The D-Jet is outfitted with relatively large slotted flaps, which were reportedly crucial to achieve the 61-knot maximum stall speed certification required by any single-engine aircraft. These flaps, which resulted in no meaningful pitch changes during retraction or extension, were designed to ease their usage. The avionics of the D-JET comprise a Garmin G1000 glass cockpit, the large multi-function display of which taking center-place on the cockpit dashboard, akin to aircraft such as the Citation Mustang. For de-icing purposes, Diamond opted for pneumatic boots on the wing's leading edges, bleed air for heating the inlets and ducts, and electric heating for the windshields and probes; in particular, Goodrich developed a considerably thinner de-icing system for the D-JET. The landing gear is electrically-actuated on later-built prototypes; atypically, the landing gear is designed to be used as an air brake during landing approaches, being deployable at speeds as high as 200 knots. Maneuvering on the ground was achieved via a nosewheel steering system, actuated via a mechanical linkage to the pedals. According to Diamond, the D-JET could be operated from 3,000-foot runways, assuming that they are both dry and uncontaminated. For details of development, click here.
