United Airlines Flight 1175
On February 13, 2018, around noon local time, a Boeing 777-222 airplane, operating as United Airlines Flight 1175 (UA1175), experienced an in-flight separation of a fan blade in the No. 2 (right) engine while over the Pacific Ocean en route to the Daniel K. Inouye International Airport (HNL), Honolulu, Hawaii. During level cruise flight shortly before beginning a descent from flight level 360 (roughly ), and about from HNL, the flight crew heard a loud bang, followed by a violent shaking of the airplane, followed by warnings of a compressor stall. The flight crew shut down the failed engine, declared an emergency, and began a drift-down descent, proceeding direct to HNL where they made a single-engine landing without further incident at 12:37 local time. There were no reported injuries to the 374 passengers and crew on board and the airplane damage was classified as minor under National Transportation Safety Board (NTSB) criteria. NTSB investigators traveled to the scene to begin an incident investigation. They found a full-length fan blade fracture in the No. 2 (right) engine, a Pratt & Whitney (P&W) PW4077 turbofan. Its installed set of hollow-core fan blades had undergone two previous overhauls at P&W that included a thermal acoustic imaging (TAI) internal inspection that is intended to prevent this type of failure. The right engine nacelle lost most of the inlet duct and all of the left and right fan cowls immediately after the engine failure. Two small punctures were found in the right side fuselage just below the window belt with material transfer consistent with impact from pieces of an engine fan blade. The damage was eventually repaired and the aircraft returned to service. Improved procedures for TAI inspection were implemented by P&W, increased frequency of TAI inspection was required by regulators, and a redesign of the inlet duct was also initiated by Boeing, all as a result of this incident and investigation. Aircraft The aircraft involved was a Boeing 777-222, the United Airlines specific variant of the original 777-200 series, registration N773UA, ( 26929) and line number 4. It was equipped with two Pratt & Whitney PW4000 engines and was 23.3 years old, having made its first flight on October 28, 1994. It was delivered new to United Airlines on September 29, 1995. Boeing stopped building the 777 with P&W PW4000 series engines in 2013, and the engine is no longer in active production. Later in 2021, N773UA was used to fly the passengers of Flight 328 from Denver to Honolulu after the aforementioned flight, operated by sister ship N772UA, suffered a similar problem. The Boeing 777 is a long-range, wide-body, twin-engine aircraft. At the time of the incident it had a relatively low accident fatality rate. The only two 777 accidents with total loss of aircraft, passengers and crew are Malaysia Airlines flights MH17 that was shot down over Ukraine in July 2014 and MH370 that disappeared over the Indian Ocean in March 2014. The other fatal accidents, Emirates Flight 521 and Asiana Airlines