Aerospace Just Solved Its Biggest Boeing 777X Engine Problem With 1 Redesign

Boeing’s 777X program appears closer to resolving a key engine certification hurdle after General Electric addressed cracking tied to the GE9X turbofan’s “mid-seal.” The mid-seal sits between turbine stages where temperatures exceed 1,000°C, and a redesign has been reported as the main factor affecting the 777X timeline and on-time delivery performance in 2026. GE, Boeing, and the FAA are working through a fix after a crack was uncovered during a shop visit for a flight-test engine. GE says the issue is isolated to a design tolerance rather than a systemic failure, and FAA-supervised corrective actions support ongoing flight tests. Boeing’s target for delivery remains 2027.