How The GE9X's 134-Inch Fan Creates Problems No Other Jet Engine Faces

A crack discovered in the GE9X engine’s mid-seal during a January 2026 inspection is being framed as more than a program hiccup for Boeing’s 777X. The problem points to how the GE9X’s extreme scaling affects components deep inside the engine core. At the heart of the challenge is the GE9X’s 134-inch (3.4 meters) fan, the largest ever used on a commercial aircraft. While it boosts efficiency—by about 10% versus the GE90—and increases bypass ratio through massive airflow, its size demands higher pressures and temperatures and puts greater stress on shafts, bearings and downstream parts. During testing, the engine has demonstrated up to 134,300 lbs of thrust.