The GE9X engine has won certification from the Federal Aviation Administration, GE Aviation said on Monday. The largest commercial turbofan in the world, the GE9X powers the Boeing 777X, the new twinjet now expected to gain certification sometime in 2022.

The GE9X’s FAR Part 33 certification involved eight test engines that completed just under 5,000 hours and 8,000 cycles. GE Aviation plans to conduct 3,000 cycles of additional ground testing on the GE9X to support Extended Operations (ETOPS) approval. The GE9X team also continues to work on maturation testing to help GE engineers prepare to support the engine in service.

Not always a smooth exercise, certification of the 9X didn’t come without its difficulties, most notably reflected in the need to retrofit redesigned Stage 2 stator vane assemblies in the engines' compressors after revamping their geometry to ensure a proper wear profile. At the time, the problem contributed to Boeing’s decision to shift its original 777X certification target from late 2019 to early 2021.

More recently, Boeing delayed expected certification by another year, to 2022, due to what Boeing CEO David Calhoun described as a need to balance supply and demand as customers began asking for later deliveries due to an expected protracted recovery for widebodies from Covid-19.

GE has delivered eight GE9X test engines and two test spares to Seattle for Boeing’s four 777X prototypes. The engine company also said it has assembled “several” GE9X production engines and remains in the process of completing factory acceptance tests.

For service and support of its customers, GE has established GE9X engine training courses at its Customer Technical Education Center (CTEC) in Cincinnati. The company uses a GE9X engine to develop lean maintenance practices it plans to implement in customer training modules and GE training procedures. Course work includes line maintenance, borescope and boroblend repair procedures, as well as fan stator removal and installation. The CTEC team is also working augmented reality/virtual reality (AR/VR) training courses to supplement the in-person training.