GE9X Mid-Seal Issue Holds Up 777-9 ETOPS Testing, Boeing Says

Boeing’s 777-9 certification campaign has run into a durability problem inside the GE9X engine, and Chief Executive Kelly Ortberg says it is holding up the extended-range twin-engine operations (ETOPS) testing that the aircraft must complete before it can enter service.

Ortberg spoke at a Morgan Stanley investor conference in the middle of September. Aviation Week reported the mid-seal problem on 16 September, and GE Aerospace later added a statement to that report.

What the issue is

The mid-seal is a component that connects the front and rear sections of the GE9X. Ortberg tied the delay directly to it: until the mid-seal certification plan is complete, Boeing cannot get authorisation to begin ETOPS flying. GE Aerospace’s chief financial officer subsequently said the company has a high degree of confidence in the redesigned seal, according to an 18 September brief from CAPA, and Aviation Week reported GE’s view that the upgrade is on track.

ETOPS approval governs how far a twin-engine airliner may fly from a diversion airport. Without it, a 777-9 cannot operate the long oceanic and remote-area routes for which airlines such as Emirates and Lufthansa ordered it.

Timeline

Ortberg has said much of the flight-test programme should be completed by the end of 2026, but that ETOPS testing will extend into 2027 and represents “the final major hurdle before certification”. That leaves certification flight testing likely to finish early in 2027, with some activity continuing past the turn of the year.

FAA Administrator Bryan Bedford said in May that he expected the 737 MAX 7 first, then the MAX 10, “and hopefully the 777 early next year”. The MAX 7 was certified on 3 August, but the MAX 10 has since been delayed by a separate software issue, so the 777X now sits behind a longer queue than that May forecast implied.

Boeing continues to say that first delivery will happen in 2027, to Lufthansa. The 777X was originally scheduled to enter service in 2020, and the programme has been slowed by increased regulatory scrutiny following the 737 MAX crisis.

Why customers care

Lufthansa, Emirates and Qatar Airways have all adjusted fleet plans and extended the lives of existing aircraft while they wait. Each month of delay keeps older aircraft in service and pushes back the efficiency gains the carriers expected from the new widebody.

The seal issue also reaches the freighter line. With the 777-8F expected around 2029, the FAA granted Boeing an exemption in September to keep building the current 777F beyond the 2028 CO2 cutoff.

What to watch next: FAA acceptance of the redesigned seal, the start date for ETOPS testing, and whether the final stages of certification can be finished in the first half of 2027.