United Airlines Flight 328

On February 20, 2021, United Airlines Flight 328 (UA328/UAL328), a scheduled domestic flight from Denver to Honolulu, suffered a contained engine failure shortly after takeoff from Denver International Airport (DEN). The aircraft, a Boeing 777-222 powered by Pratt & Whitney (P&W) model PW4077 turbofan engines, experienced a fan blade separation due to metal fatigue causing an engine fire and extensive damage to the nacelle. Despite being classified as a contained failure, as the fan blade fragments remained inside the nacelle, large parts of the engine's cowling, inlet and thrust reverser detached, creating a debris field over 1 mile (1.6 km) long across residential areas of Broomfield, Colorado. The falling debris damaged private property, including the roof of a home and a parked vehicle. Witnesses captured footage of falling debris on smartphones and a dash cam, while passengers recorded video of the damaged engine and posted it to social media. The fuselage sustained minor damage, but the crew was able to shut down the affected engine and return safely to Denver, landing on runway 26 at 1:28 pm MST (06:28 UTC), 24 minutes after departure. No injuries were reported among the 231 passengers and 10 crew, or on the ground. The U.S. National Transportation Safety Board (NTSB) opened an investigation into the incident. In response, the U.S. Federal Aviation Administration (FAA) issued an Emergency Airworthiness Directive requiring immediate inspection of Pratt & Whitney PW4000-series engine fan blades before further flight. Similar 777-200 aircraft were temporarily grounded by multiple aviation regulators around the world. Japan Airlines, which had experienced a similar engine issue in December 2020, retired its PW4000-powered 777-200s earlier than planned in March 2021. United Airlines, which also had a similar incident in February 2018, grounded its fleet of PW4000-powered 777-200s from early 2021 until July 2022.