Design work began in 2006 under the codename SMS for super-midsize, and was envisioned to compete with the Hawker 4000, the Bombardier Challenger 300 and the Gulfstream G200 or the Embraer Legacy 600 with a range. Few details were publicized, except that the model was to be powered by two 10,000-pound-thrust Rolls-Royce RB282 engines. The project was revamped after the 2008 recession when demand for super midsized and smaller aircraft decreased dramatically, while demand for the large-cabin, long-range models remained vigorous. In 2009, the design was re-evaluated and the engine choice was reassessed. The 5X was unveiled at the National Business Aviation Association's annual convention on October 21, 2013, to be powered by two Snecma Silvercrests. Compliant Silvercrest engines were originally planned for the end of 2013 but technical issues led Safran to postpone them to the end of 2017, leading to delay the 5X introduction from 2017 to 2020, and the high pressure compressor issues in the fall of 2017 delayed it further with performance shortfalls, preventing a 2020 service entry. On 29 January 2016, Dassault Aviation confirmed a two-year delay and production freeze on the Falcon 5X because of ongoing problems with the Snecma Silvercrest engine. As Dassault endured a near three-year delay to 2020 with 12 cancellations in 2016, it demanded compensation from Safran for the engine delays. After ground tests in spring 2017 including low and high speed taxi, the 5X made its first flight from Bordeaux–Mérignac Airport with a preliminary version of the engines on July 5, 2017. The preliminary flight tests were intended to streamline the development program, leading to full flight testing in 2018. That program was planned to fly with certifiable engines for flight validation and type certification, "limiting the consequences of the four year engine development delay as much as possible". It was then scheduled to enter service in 2020. In October 2017, the prototype went through 50 flight hours, testing system performance and basic handling qualities. Dassault then announced the aircraft's service introduction could be further delayed after Safran discovered high-pressure compressor response problems at high altitudes and low airspeeds on its flying testbed in San Antonio. Dassault did not rule out switching its engine supplier at that point. The prototype reached Mach 0.8 and 41,000 ft.
Falcon 6X
On 13 December 2017, Dassault abandoned the Silvercrest due to technical and schedule risks, ending the 5X development. In its place the company launched a new Falcon model with the same fuselagecross section, Pratt & Whitney Canada engines and a range, planned for a 2022 introduction. The new jet will use Pratt & Whitney Canada PW800s, already powering the Gulfstream G500/G600. The design was unveiled in February 2018, is forecast to make its first flight in early 2021 and begin deliveries in 2022. Dassault hopes to launch a larger and longer-range variant of the 6X, to compete with the 7,700nm -range Bombardier Global 7500 and the 7,500nm-range Gulfstream G650ER. On 6 September, Dassault Aviation and Safran ended their dispute with US$ 280 million in compensatory damages paid by Safran to Dassault. By October 2018, Dassault had started construction of the lower wing and rear fuselage parts. By February 2019, its PW812D variants had accumulated 120h of flight tests. By May 2019, the design was frozen, the engines had 1,000 h of test time, and assembly was expected in 2020 for an on-track program. By October 2019, the first aircraft's front, main and rear fuselage sections were completed before being assembled and joined with the wing in early 2020.
Design
The Falcon 6X is largely based on the Falcon 5X aerodynamics and systems, validated during its preliminary flight test program, but it is optimized to take advantage of its PW812D engines for a longer cabin and a greater range, a Mach 0.90 top speed and a Mach 0.85 cruise. Its cabin is long, can accommodate 16 passengers in three zones with 29 windows including a galley skylight and is high by wide, the largest purpose built business jet cross section. A front-fuselage extension makes its cabin longer. The Falcon 6X reinforces the 5X new wing and keeps its digital flight control system and Honeywell Primus Epic EASy III flight deck. The new engine fans will have a diameter of shorter than in the Gulfstreams, and with four low-pressure turbine stages instead of five, engine weight is reduced by. Its empty weight increases by or 5.7%, from, due to heavier engines, fuel system and structural reinforcements.
