Boeing 777X Flight Tests Halted After GE9X Incident

Originally published on Airways

Boeing has temporarily suspended Boeing 777-9 test flights after an unspecified issue occurred on the aircraft’s General Electric 9X engine. The issue was found during a borescope inspection of a flight test engine. Boeing is looking into the problem in a joint investigation with GE Aerospace. 

Both Boeing and GE Aerospace need to find out whether the issue was limited to the specific engine, a production batch, or if it is a design flaw. During the runs, GE stated that the temperature alert was observed and the operator was able to shut down the engine normally. The specific GE9X engine that was involved with the issue is the highest-time engine with over 2,600 cycles and over 1,700 hours.

Emirates (EK) President Tim Clark stated via aviationweek.com that if the problem with the engine was serious, it would hold up approval from the FAA for the aircraft. This would already push back the already delayed FAA approval for the aircraft.

As of now, EK, which is the launch customer of the Boeing 777-9, still hopes the aircraft will be approved by the FAA by summer 2025 when it plans on debuting the aircraft.

Boeing is testing the GE9X on the Boeing 777-9 aircraft registered WH001. Until October 6, WH001 was the only test aircraft flying. According to Aviation Week, the issues came as the aircraft was tested by conducting thermal exceedance evaluations. 

Like the Boeing 777X engine, the GE9X has also faced problems. GE delayed the first flight of the GE9X, which was scheduled for February 2018, because of problems with the high-pressure compressor and durability issues.

This led to a redesign of the compressor, which delayed the first Boeing 777-9 by six months until January 2020. Previously, the manufacturer planned to take off with the aircraft by the end of 2019.

GE9X Engine. Image: GE

Comments by Boeing, GE, and Emirates Officials

Boeing states, “We are supporting GE Aerospace as they assess a recent GE9X engine issue and will resume airplane testing once their thorough process and appropriate actions are complete. Safety is our top priority, and our supplier and technical teams will take the time necessary to support the review as we work transparently with our customers and regulators.” 

Emirates CEO Tim Clark commented, “On Dec. 6 we get the information about whether the engine is good to go, in other words, was it a batch [issue] or an issue with the whole design of the engine… That affects the ability to get the flight test program going; Boeing wants to restart it in January.”

The EK CEO added, “The TIA, which is meant to be sometime by the middle of next year moves pro rata. If GE has to go back to [do a] redesign and then go through the whole testing process again, it moves back month on month.”

A spokesperson for General Electric stated, “GE is reviewing a technical issue that occurred during GE9X post-certification engineering testing, and we are closely coordinating with Boeing on our findings to support their return to flight testing.”

This is a developing story.