Boeing has resumed test flights for the 777X wide-body aircraft following a two-month hiatus.
The flight test program was resumed on December 17, 2022, with the 777-9 jet flight BOE1 from Boeing Field (BFI) in Seattle. According to Flightradar24.com data, the aircraft registered N779XW was scheduled to land in Moses Lake (MWH), but the plane returned to BFI airport instead.
The 777-9 was scheduled to operate a similar flight between Seattle and Moses Lake two days later on December 19, 2022. However, after 30 minutes spent in flight, the flight history suggests that the plane was diverted to the Boeing Field.
The plane was last spotted in the skies on December 21, 2022, when the aircraft performed three test flights, including a returning flight between Seattle (BFI) and Spokane (GEG).
“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 confirmed in a statement to FlightGlobal on December 21, 2022.
GE9X engine issues
N779XW is one of four 777X jet prototypes involved in the testing process, which was launched in January 2020. However, it remains the only plane to operate test flights following a technical engine incident which occurred during post-certification on October 6, 2022.
N779XW was undergoing several test flights between Seattle and Moses Lake in the United States when one of its GE9X engines failed.
The engine had already completed more than 2,600 flight cycles and around 1,700 hours of run time on the day of the incident. Although the engine problem has not yet been solved, results of a borescope inspection conducted by GE Aerospace showed a fault in the flight test engine temperature sensor.
None of the other three 777Xs have flown since the incident after Boeing temporarily suspended the testing process.
According to Boeing, delivery of the first 777X jet is expected to take place in 2025. However, it is still not clear if issues with the GE9X engine will force Boeing to adjust the certification program.