Engine certification snag complicates Boeing’s path to 777-9 extended-range approval

A durability issue with a component inside GE Aerospace’s GE9X turbofan is holding up Boeing’s ability to begin extended-range flight testing of the 777-9, according to comments from both companies at a Morgan Stanley investor conference in mid-September.

The problem centres on the engine’s mid-seal, a part that links the front and rear sections of the GE9X and balances power between turbine stages. GE has acknowledged the original design proved less durable than expected and has developed a redesigned version, but the FAA has yet to certify the fix.

Boeing chief executive Kelly Ortberg said on 16 September that the Federal Aviation Administration will not sign off the airframer’s flight-test plan for the 777-9’s extended-range twin-operations (ETOPS) certification — the approval that lets twin-engine aircraft fly long overwater and remote routes — until it receives GE’s certification plan for the redesigned mid-seal. “Until we get the mid-seal certification plan complete, we can’t get authorisation to start that ETOPS [flight testing],” Ortberg said, adding he expects it “very soon” but that the issue will “probably… cause us a little bit of a challenge between now and the end of the year.”

Despite the timing friction, GE chief financial officer Rahul Ghai stressed the following day that the redesigned part is not actually a prerequisite for ETOPS approval itself. “The ETOPS certification does not need the new mid-seal. The existing mid-seal works. That was always the plan,” he said, noting that FAA testing of the redesign should conclude “in the next few months.”

GE says it has already built the new mid-seal into its production line and began delivering updated GE9X engines to Boeing this quarter. The company’s shares closed at $325.48, down 2.98% from the previous close of $335.49, valuing GE Aerospace at roughly $337.7 billion.

For its part, Boeing says the broader type certification effort remains on track, with flight tests progressing under the aircraft’s type inspection authorisation (TIA). Ortberg reiterated that first 777-9 deliveries are still planned for 2027, and 777-9 programme leadership has said the jet will enter service with a 180-minute ETOPS clearance. He also flagged a separate risk: a potential strike by engineers represented by the Society of Professional Engineering Employees in Aerospace (SPEEA), with whom Boeing is negotiating a new four-year contract.

Source: original release

What to watch

• FAA acceptance of GE’s mid-seal certification plan and completion of testing in the coming months.
• Boeing’s start of ETOPS flight testing on the 777-9.
• Progress toward planned first deliveries in 2027.
• Outcome of the SPEEA contract vote and negotiations.