A United flight from Denver to Honolulu made an emergency landing shortly after takeoff Saturday as pieces of the engine’s casing rained on suburban neighborhoods. None of the 231 passengers or 10 crew were hurt, and the flight landed safely.
Robert Sumwalt, chairman of the National Transportation Safety Board, said during a virtual news conference Monday night that a fractured fan blade found in the engine had visible signs of “damage consistent with metal fatigue.” The broken blade hit and fractured the blade next to it as the engine broke apart, according to a preliminary investigation.
Sumwalt said the blade that fractured first was flown on a private jet to Pratt & Whitney’s headquarters Monday night to be examined under the supervision of NTSB investigators.
“Our mission is to understand not only what happened, but why it happened, so that we can keep it from happening again,” he said.
The FAA directive said the agency would review the results of the inspections “on a rolling basis.”
“Based on the initial results as we receive them, as well as other data gained from the ongoing investigation, the FAA may revise this directive to set a new interval for this inspection or subsequent ones,” according to the order.
The order means fan blades will need to be shipped to Pratt & Whitney for thermal acoustic imaging tests, the company said in a statement. About 125 Boeing 777 aircraft are powered by the PW4000-112 engine covered under the directive.
The previous inspection interval for Pratt & Whitney PW4000 engines was 6,500 flight cycles. A flight cycle is defined as one takeoff and landing.
Video posted on Twitter from Saturday’s emergency showed the engine fully engulfed in flames as the plane flew. Freeze frames from a different video taken by a passenger sitting slightly in front of the engine and also posted on Twitter appeared to show a broken fan blade in the engine.
Passengers said they feared the plane would crash after an explosion and flash of light, while people on the ground saw huge chunks of the aircraft pour down, just missing one home and crushing a truck. The explosion, visible from the ground, left a trail of black smoke in the sky.
FILE - This Saturday, Feb. 20, 2021, file photo provided by Hayden Smith shows United Airlines Flight 328 approaching Denver International Airport, after experiencing a "right-engine failure" shortly after takeoff from Denver. The Federal Aviation Administration has ordered airlines in the United States to ground planes with the type of engine that blew apart after takeoff from Denver this past weekend until they can be inspected for stress cracks. The order applies to airplanes equipped with certain Pratt & Whitney engines, which are used solely on Boeing 777s. (Hayden Smith via AP, File)
Credit: Hayden Smith
Credit: Hayden Smith