GE9X Engine For Boeing 777X Earns FAA Certification

GE9X production engine
One of the first GE9X production engines.
Credit: GE Aviation

GE Aviation’s GE9X, the largest aircraft engine yet developed, has received FAA certification, marking a major step toward entry-into-service on the Boeing 777-9, the first of the 777X family, in 2022.

Although certification tests were held up for several months in 2019 following the discovery of stator durability issues in the high-pressure compressor, GE cleared a redesign in time for the start of 777-9 flight tests in January. Eight GE9X engines, plus two spares, have so far been delivered to Boeing including powerplants for the fourth and final 777-9 test aircraft. That aircraft joined the certification campaign on Sept. 20. 

The test engines accumulated just under 5,000 hr. and 8,000 cycles during the certification program which included flights on the company’s 747-400 flying testbed. Overall, 72 GE9X test flights, totaling more than 400 hours, were flown on the 747 which first flew with the engine in the left inboard wing position in March 2018.

With FAR Part 33 engine certification completed, GE is also completing factory acceptance testing of the first batch of production GE9X units – deliveries of which to Boeing are expected to begin in the fourth quarter. The company also continues to run ground tests of engines in support of Extended Operations (ETOPS) approval and maturation as part of preparations for supporting engines in service. Pre-certification work also included 1,000 cycles of test time for the Initial Maintenance Inspection which establishes the maximum hours or cycles of service between maintenance intervals.

Aside from the 134-in. dia. fan, which comprises 16 composite blades, the GE9X is distinguished by an overall pressure ratio of 60:1, which is the highest for any commercial engine, as well as the incorporation of more than 300 additively manufactured parts. The engine also utilizes five components made from ceramic matrix composites including the first-stage shroud and first and second-stage nozzles on the high-pressure turbine, and the inner and outer linings of the combustor.

Commenting publicly on a GE engine program for the first time since taking the helm at the start of the month, GE Aviation President and CEO John Slattery describes the GE9X as a “game-changing product” and adds that “there is no substitute that can achieve the combination of size, power and fuel efficiency.”

Editor's Note: This article was changed to clarify the final pre-certification task testing.

Guy Norris

Guy is a Senior Editor for Aviation Week, covering technology and propulsion. He is based in Colorado Springs.