Aircraft
Investigators Find Metal Fatigue in UAL 777’s Failed Engine
NTSB chairman Robert Sumwalt said that a fan blade from the PW4000 that failed in-flight on February 20 showed so-called "beach" marks.
NTSB investigators record the damage to the PW4000-112 engine that failed on a United Airlines Boeing 777-200. (Photo: NTSB)
NTSB investigators record the damage to the PW4000-112 engine that failed on a United Airlines Boeing 777-200. (Photo: NTSB)

National Transportation Safety Board investigators have found evidence of fan blade metal fatigue in the Pratt & Whitney PW4000-112 engine that failed in flight on February 20, raining nacelle debris over a mile-long area of a Denver suburb and leading to the grounding of 69 Boeing 777-200s still in service.