Boeing is approaching a key milestone in its progress toward certification of the 777X—type inspection authorization (TIA)—as it continues to target 2025 for U.S. FAA approval. The company brought flight test vehicle WH001, a 777-9, to the Dubai Airshow this week as it looks to build momentum and perhaps reassure customers about the program that has garnered orders for well over 300 of the widebodies.
TIA would kick off formal FAA participation in flight testing toward certification credit. The test program has already accumulated 3,000 hours and 1,000 cycles, and John Dyson, senior product and services marketing specialist for Boeing, said the company has already conducted most of the testing planned for the FAA certification flight trials in advance of TIA.
“TIA is really the big milestone that once we hit it, [we can] kind of a sprint through the flight test program,” he said, adding that the company has worked closely with the FAA all along and that it continues to learn from its other programs, including the 737 Max 7 and Max 10.
While unable to provide a definitive time for certification, he said that based on the remaining work balance, the company expects the 777X to enter into service "sometime in 2025.”
The development program has four aircraft in flight test. Dyson called WH001 “the workhorse of our fleet,” but three participate in various aspects of flight controls, avionics, and other testing. Boeing fit the fourth with a full interior mockup to test the cabin components.
Launched in 2013, the 777X uses new GE9X engines, which produce a record 134,300 pounds of thrust, according to GE Aerospace. The design produces a 10 percent improvement in specific fuel consumption over the GE90-115B, which powers the 777-200LR and 777-300ER. Dyson said the engines have run "well within the fuel efficiency projections.”
Other features include composite wings with folding wingtips. The folding wingtips build on Boeing's expertise through its F-18 and are built in Saint Louis, across the street from the F-18 production site. Dyson explained the importance of the folding ability given the aircraft’s 235-foot span, the longest in the industry. The feature ensures the ability to park at existing gates at more than 200 airports globally. “Wherever a triple seven applies today, this airplane can fly as well,” he said.
The aircraft also has a lower cabin altitude of 6,000 feet, four additional inches of cabin width that permits 10-abreast seating, and other technologies and advancements borrowed from the 787.
Boeing remains in negotiations over the launch operator, with a few seeking that position. Overall, Dyson said interest has picked up in the aircraft as it has begun to regain momentum in the certification program, characterizing sales activity as “really busy.”
Originally slated for certification in 2020, the program had encountered delays primarily as it assessed what it would need from a more regimented FAA certification program. The delays have hindered fleet replacements as the 777 no longer has a direct competitor in its space.
To that point, Dyson noted: “There’s nothing that can replace a 777 but a 777.”