[4] In early 2008 the high pressure spool and combustor have been run in a US$120 million core-demonstrator called SM-X, reaching the take-off speed of 20,300rpm.

[12] In October 2017, after Safran discovered high-pressure compressor response problems at high altitudes and low airspeeds on its flying testbed in San Antonio, Dassault announced the Falcon 5X introduction could be further delayed after 50 test flight hours, and do not rule out switching its engine supplier.

Flowpath will not be too modified and no stages or vanes will be added, the fixes selection will establish the length of the delay and the schedule will be revised before 2017 ends to recover all the surge margin and to operate as planned across the flight envelope.

[16] On 13 December 2017, Dassault abandoned the Silvercrest due to technical and schedule risks, ended the 5X development and launched a new Falcon with the same cross section, Pratt & Whitney Canada engines and a 5,500 nmi (10,200 km) range for a 2022 introduction.

[19] In May 2018, Safran announced it had launched a high-pressure compressor redesign for a go-ahead decision by the middle of 2019, after testing, shelving the Hemisphere program if problems cannot be fixed.

[23] In July 2019, Textron suspended the Cessna Citation Hemisphere development as its turbofans did not meet objectives: the new high pressure compressor exceeded expectations during ground tests but further trials were necessary to "confirm engine improvements and complete overall engine performance and durability validation" and Safran would continue the effort as an "R&T platform".

[28] The two-shaft engine architecture includes a 42.5 in (108 cm) fan with solid wide-chord swept blades, followed by 4 booster stages, all driven by a 4-stage low pressure turbine.