The Boeing 777X test aircraft WH004 (registration N779XZ) has taken to the skies over Seattle for the first time in more than three and a half years. This prototype took off from Seattle Paine Field International Airport (PAE) on May 7 for a two-hour flight. WH004 completed its maiden flight in September 2020 but was retired from service at the end of 2021 so Boeing could focus on its other three 777X test aircraft. This particular aircraft is the only one in the test fleet equipped with a full passenger cabin, allowing the company to test cabin systems.
The resumption of test flights with WH004 indicates that testing of the 777X is entering its final phase. The full-cabin configuration allows Boeing to investigate key aspects such as the climate system and in-flight noise under real-world conditions. According to AirDataNews, Boeing plans to receive type certification from the U.S. Federal Aviation Administration (FAA) by the end of 2025, allowing for first deliveries to begin in 2026.
The return to service of WH004 was a complex process, as the aircraft had been in storage since late 2021. The test team conducted several months of maintenance and preparation to get the aircraft ready for flight again. Levi King, the aircraft maintenance manager for the test flights, praised his team's efforts and emphasized that the successful reactivation of this aircraft represents an important step toward the program's certification.
Extensive test program to validate the 777X
The Boeing 777X test fleet, consisting of four 777-9 test aircraft, has completed over 1.400 flights and accumulated nearly 4.000 flight hours. Over the past few years, the aircraft's safety, reliability, and performance have been intensively tested. The flight of WH004 marks the beginning of flight testing of the cabin systems for commercial service. Anita Rudack, deputy project manager for 777-9 flight test, emphasized the company's commitment to safely and successfully completing the test program to deliver this exceptional aircraft to customers.
The 777X, whose development began in 2011, is intended to compete with the Airbus A350 XWB. Despite construction beginning in 2017 and its first flight in 2020, the 777X is still nearing completion of its testing phase. The tests now underway with a fully configured passenger cabin are a clear sign of progress in the certification process.
The Boeing 777X will be available in three variants: the 777-8, the extended-body 777-9, and the freighter version of the 777-8, the 777-8F. The 777-9 is enjoying the most orders. Airlines that have already placed firm orders for the 777X include Air India, ANA, British Airways, Cathay Pacific, Emirates, and Lufthansa. As of March 31, Boeing had received 521 net orders for the 777X.