The US National Transportation Safety Board (NTSB) has released its final report on the crash of United Airlines Flight 328. failure On February 20, 2021, in the engine shortly after departure from the Denver airport. The report concludes that there is probable cause for the incident Failure due to right turbine blade wear.
According to NTSP, the failure Turbine blade was partly due to Adequate studies It does not recognize signs of cracking At a lower level. In addition, inadequate spacing of inspection intervals by manufacturer Pratt & Whitney allowed cracks to go unnoticed and ultimately resulted in wear failure.
The report also notes that the severity of engine damage increased following blade failure design and turbine inlet testing. These components do not ensure that the inlet will adequately dissipate energy from an in-flight fan blade loss event, limiting further damage.
Fortunately, there were no injuries to passengers or crew. There were no injuries on the ground due to debris falling from the plane during its safe return to the runway in Denver. However, one vehicle and a residence were damaged due to damage to the intake lip skin and fan fairing support.
Police in Broomfield, Colorado showed up Photos of debris from this Boeing 777-200 It took off for Honolulu and made an emergency landing 24 minutes after takeoff.
After the incident in February 2021, the United States Federal Aviation Administration (FAA) All flights were suspended It has been registered in the country with the same PW4000 series machines for more than a year.
The Denver emergency occurred less than three years after a Southwest Airlines passenger broke off a fan blade on another model, dislodging parts of the engine casing and impacting the plane. Other fan blade failures occurred on a United flight to Hawaii in 2018 and a Japan Airlines Boeing 777 in 2020.
This series of events raised concerns that long-held assumptions about fan blades were wrong: they failed much sooner than expected. The FAA required more frequent inspections.
Broken Blade on Denver is subject Broad facility in 2014 and reviewed again in 2016. Second, the software detected two “low-level symptoms” on the blade, but an analyst concluded they were either camera “noise” or a loose grid.
The NTSB said the blade should have been taken apart, repainted and re-examined or the “unclear indications” should have been sent to a team for further review. The NTSB said it doesn’t appear either one or the other happened.
At the time, these inspections were mandatory every 6,500 flights, and the blades did not need to be replaced until they passed the inspection.
(With information from AP)