Boeing 777X test model, N779XX, successfully retook flight last week after a hiatus of nearly half a year. This model, along with three other pre-series models, has been undergoing test flights since 2020 but has faced some challenges. The model, N779XX, resumed testing almost a month after its sister model, N779XW, resumed its test flights following a two-month pause to address engine issues. While Boeing aims to begin delivering the aircraft to airlines in two years, challenges in the certification process may delay deliveries.
Second 777X Test Aircraft Successfully Takes Flight
The second 777X test aircraft, N779XX, successfully took off from Seattle’s Boeing Field (officially known as King County International Airport) on January 13, according to Aviacionline. This test model will now join N779XW in the certification process.
FlightAware data shows that N779XX left BFI at 11:46 and flew for nearly 2 hours. The aircraft reached a cruising altitude of 37,000 feet and a speed of 552 mph. It reportedly performed two approaches during the flight. It made a brief stop at Grant County International Airport in Moses Lake, Washington, before returning to BFI, mentioning that the plane’s last flight was on August 14, 2022.
Boeing’s 777X Test Fleet
Boeing has manufactured four pre-series models of the 777X: N779XW, N779XX, N779XY, and N779XZ. As per Aviacionline, N779XY was grounded in July, and N779XZ completed only one flight in 2021 and has not flown since. N779XW resumed flights in December after being grounded for two months. The two remaining test aircraft are expected to return to the skies later this year. Reports indicate that N779XY is scheduled to resume test flights in April, and N779XZ is scheduled to return to testing in July.
There is also a fifth test, 777X, that was intended for testing the aircraft’s interior and exterior, but there is no confirmation whether it will be used. The goal of returning the four primary test aircraft to the skies is to reach Type Inspection Authorization (TIA), which will enable Federal Aviation Administration (FAA) experts to board the plane and begin final certification, according to reports.
Challenges of GE9X Engine Issues on 777X Certification and Delivery Timeline
The 777X is equipped with the latest GE9X engines, the world’s biggest aircraft engines. As part of the certification process, test flights have been conducted to ensure the engines and technology are functioning properly and safely. Recent groundings related to engine issues have raised concerns among some airlines about the delivery timeline of the aircraft.
Dubai-based Emirates, an airline that operates only widebody planes, has been eagerly awaiting the certification of the new 777X aircraft. The carrier is keeping older and less efficient Airbus A380s in its fleet to maintain operations and capacity. Tim Clark, Emirates CEO, stated that the airline is not expecting to receive its first 777X until at least 2025.