Key Points:

  • The February 2021 United Airlines Boeing 777 engine failure was due to a fan blade crack, according to a report by the National Transportation Safety Board (NTSB).

  • Following the incident, FAA ordered immediate inspections of other aircraft with similar Pratt & Whitney 4000 engines, leading to grounding for over a year.

  • Post the incident, enhanced safety measures were introduced, including more rigorous fan blade inspections and necessary modifications.

United Boeing 777’s Grounding Traced Back to Fan Blade Crack

WASHINGTON D.C. —The National Transportation Safety Board (NTSB) pinpointed a fan blade crack as the primary reason behind the engine failure experienced by a United Airlines Boeing 777 in February 2021 in Colorado. The board brought inadequate inspections under scrutiny as a secondary cause.

The incident, which happened shortly after the flight's departure from Denver en route to Honolulu, resulted in debris scattering over nearby cities. Fortuitously, the mishap did not lead to any injuries, and the aircraft managed a safe return to its takeoff point. Following the failure, an immediate halt on further flights involving 777 aircraft equipped with Pratt & Whitney 4000 engines was called by the Federal Aviation Administration (FAA), a move that grounded the planes for a duration exceeding a year.

United Airlines conveyed its cooperation throughout the investigation in a statement released on Friday. The airline expressed its collaboration with pertinent entities including the NTSB, FAA, Boeing, and Pratt & Whitney, highlighting their contentment in having the aircrafts operational again in their fleet.

Pratt & Whitney, a subdivision of RTX, remained silent without offering any immediate remarks in response to the NTSB’s statements, which spotlighted “the inadequate inspection of the blades” as well as “the insufficient frequency of the manufacturer’s inspection intervals.” According to the NTSB, these lapses allowed "low-level crack indications to propagate undetected," leading to the fatigue failure.

Almost a year after the incident, in March 2022, the FAA instituted new safety directives, propelled by this and two other reported in-flight fan blade failures. These directives were established to augment inspection protocols and induce modifications to forestall similar occurrences in the future. Reaffirming its dedication to aviation safety, the FAA cited the formulation and implementation of these measures as its reactive approach to the fan blade incidents, emphasizing its responsive action on Friday.