GE Aerospace fixes engine seal flaw that threatened Boeing 777X timeline

GE Aerospace ↘ 0.15% has completed a redesign of a cracked turbine mid-seal inside the GE9X engine, resolving a technical problem that had hung over Boeing's The Boeing Company ↗ 2.76% long-delayed 777X program for much of 2026. The fix clears the way for production engines incorporating the new part to be delivered for early 777-9 customer aircraft, according to reporting by Simple Flying and InsideFlyer.bloomberg+1

From Discovery to Redesign

The crack was first identified during a routine shop visit on a flight-test engine in January 2026. The mid-seal, which manages temperature and pressure between turbine stages where conditions exceed 1,000 degrees Celsius, sits deep inside the core of the world's largest commercial turbofan. Bloomberg first reported the durability concern in February, noting it could require a redesign and retrofit during future maintenance overhauls. Reuters reported at the time that Boeing CEO Kelly Ortberg said the issue would not affect deliveries scheduled for 2027.usnews+3

GE determined the crack stemmed from a specific design tolerance issue rather than a systemic failure. In April, FlightGlobal reported GE was still working on the fix but insisted it would not cause further delays to the 777-9 timeline. By mid-2026, GE's earnings calls confirmed that tooling changes were underway and suppliers were ramping up for the revised component.simpleflying+2

Certification and Delivery Outlook

With the redesign now finalized and FAA-overseen corrective actions completed, Boeing has continued flight testing uninterrupted. The FAA's certification timeline remains intact, though the agency signaled earlier this year that approval would likely come in 2027 rather than 2026. Lufthansa is expected to receive the first production 777-9.visaverge+4

However, the fix introduces retrofit obligations for existing engines. Earlier this year, Boeing struggled to place roughly 20 already-built 777X airframes with launch customers Emirates, Lufthansa, and United, which reportedly balked at the high cost of structural and engine retrofits on aircraft that had sat idle for years.simpleflying

Competitive Pressure Remains

The resolution removes one obstacle, but the 777X program — now approaching seven years behind its original schedule — still faces competitive pressure. Air Canada bypassed the jet in favor of the Airbus A350-1000, citing delivery certainty. Analysts at Leeham News have noted that propulsion issues, rather than airframe certification, are now the priority for the program's development. The first batch of production GE9X engines is expected in late 2026 to early 2027, and their performance in FAA conformity inspections will determine whether Boeing's 2027 delivery target holds.insideflyer+1