Boeing Responds After Suspending 777X Test Flights

The discovery was made over the weekend and the grounding of the test aircraft announced on Monday.

According to Boeing, the thrust link is a structural component between the engine and the airplane structure. The thrust link is designed to transfer thrust between the engines and pylons that attach the engine to the airframe.

"This part is custom to the 777-9, and each 777-9 engine includes two of this component so there is redundancy," the company told FLYING in a statement. "We are keeping the FAA fully informed on the issue and have shared information with our customers."

The FAA confirmed that Boeing had notified the agency about the situation and was taking steps to assess the issue.

A thrust link is described as a "heavy titanium component" that is not part of the engine itself. The 777X is powered by the General Electric GE9X, which has a 134-inch front fan, sitting in a cowling measuring 11 feet across. According to GE, it is the largest and most powerful engine in the world and also has more fuel efficiency than its predecessors.

Boeing told FLYING that no near-term flight tests were planned on the other flight test airplanes, which have scheduled maintenance and layup activities.

There are three 777X aircraft being used for test flights. One a is located in Hawaii, and the other two are at King County International Airport-Boeing Field (KBFI) in Seattle and Snohomish County Airport-Paine Field (KPAE) in Everett, Washington.

According to the Seattle Times, maintenance technicians discovered cracks in the thrust link after a 777X landed in Hawaii on Friday. Boeing immediately inspected the other two test aircraft and discovered cracks in them as well.

The Boeing 777X was unveiled in 2013 and took its first flight in 2020. Deliveries of the aircraft, which have not yet been certified by the FAA, are slated to begin in 2026.