Boeing has resumed flight testing of its 777X airframe after Boeing and GE worked on issues with the GE9X engine reported last month. Since December 17, N779XW has been flying and has finished three days of testing from its base in Seattle. Let’s learn more.

What happened to the 777X?

On November 30, Boeing temporarily halted test flights for the 777-9 after the aircraft’s General Electric 9X engine experienced an unspecified issue. And it was unknown whether the problem only affects this particular engine, a specific production run, or—possibly more seriously—a recently discovered design flaw.

Temperature sensor triggered

GE Aerospace said: “We had a finding during a borescope inspection of a flight test engine and decided with Boeing to remove the engine and send it to our test facility in Peebles, Ohio for engineering test runs.”

During the runs, GE stated that the temperature alert was observed, and the operator could 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.

Returned to the skies

Before the aircraft can take to the skies again, much less acquire regulatory certification for commercial operations, any engine anomaly must be thoroughly tested and resolved. Even though it seems like the problem hasn’t been resolved yet, steps have been taken to allow test flights to resume.

The test program for the 777-9 has officially resumed, as first noted by FlightGlobal. On December 17, N779XW took off from Boeing Field (BFI) in Seattle and traveled for almost an hour and a half over Washington and Montana before landing back at BFI. Since then, the aircraft has been very active, taking to the skies once more on December 19 before heading to Spokane Airport (GEG) on December 21 for additional testing. In a statement to FlightGlobal, Boeing said:

“We have resumed airplane testing following our comprehensive safety process and appropriate mitigations while our supplier and technical teams continue their work. We’re supporting GE Aerospace as they continue to assess a recent GE9X engine issue.”

Boeing

Could there be a delay in the delivery of the 777X?

Emirates, one of Boeing’s biggest clients, has recently been a vociferous critic of the company. The carrier has been obliged to maintain outdated 777s and A380s in the fleet after the projected replacement, according to CEO Tim Clark, who has been vocal about 777X delays. Clark worries that Boeing’s target delivery date of the first quarter of 2025 may be slipping away. In November, he said:

“The July 2025 delivery date we estimate is something I said, not Boeing. They said they want to deliver by the end of 2024 or first quarter of 2025. I said judging by their performance today, we make that July 2025. And Boeing Commercial CEO Stan Deal agreed.”

Sir Tim Clark, Emirates’ CEO

Although no one wants this to happen, delays are extremely likely because of the FAA’s enhanced scrutiny of the 777X clearance procedure. Despite numerous speed bumps, the 777-9’s trip is still ongoing for the time being.

Read also: The Differences Between the Boeing 777 Variants

Source: FlightGlobal

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