The National Transportation Safety Board (NTSB) announced on Friday that the engine failure of a United Airlines Boeing 777 in Colorado in February 2021 was due to a fan blade crack. The NTSB pointed out that insufficient inspections were a contributing factor.
.gif)
Following the incident, the Federal Aviation Administration (FAA) mandated immediate inspections of 777 aircraft equipped with Pratt & Whitney 4000 engines, resulting in the grounding of these planes for over a year. The affected Boeing 777-200, en route to Honolulu from Denver, scattered debris over nearby cities, but there were no injuries and the plane returned safely to the airport.
The NTSB blamed the incident on inadequate blade inspections that failed to detect early signs of cracking and infrequent inspection intervals set by the manufacturer, which allowed the cracks to grow undetected, leading to fatigue failure. Pratt & Whitney, an RTX unit, did not comment immediately. United stated on a Friday that it had worked closely with the NTSB, FAA, Boeing, and Pratt & Whitney throughout the investigation and was glad to have these aircraft back in service.
In March 2022, following three reported in-flight fan blade failures including the Colorado incident, the FAA issued new safety directives requiring enhanced inspections and modifications. Boeing stated that it has since identified design changes to enhance the structural integrity of the engine inlet and cowling and has been updating the FAA, Pratt & Whitney, and airline customers on its progress. United is the only U.S. operator of 777s with PW4000 engines and had 52 such planes in 2022. As of January, 17 confirmed cracked fan blades have been found according to the NTSB, with the first one identified in December 2004 - excluding three fan blades that experienced full-blade separation during service.