WASHINGTON (Reuters) – US National Transportation Safety Board (NTSB) Chairman Robert Sumwalt said Monday that damage to a fan blade on a failed Pratt & Whitney engine in a Boeing United Airlines 777-200 is consistent with metal fatigue, according to a preliminary report. evaluation.
At a press conference, Sumwalt said it was unclear whether Saturday’s PW4000 engine failure with a “heavy knock” four minutes after takeoff is consistent with another engine failure on another United flight bound for Hawaii in February. 2018 which was attributed to fatigue. fracture in a fan blade.
The engine that failed in the 26-year-old Boeing Co 777 and spattered parts in a Denver suburb was a PW4000 used in less than 10% of the world’s fleet of 777 wide-body aircraft.
In another incident at Japan Airlines (JAL) 9201.T 777 with a PW4000 engine in December 2020, the Japan Transportation Safety Board reported that it found two damaged fan blades, one with a metal fatigue crack. An investigation is ongoing.
The focus is more on engine maker Pratt & Whitney and analysts expect little financial impact on Boeing, but the PW4000 woes are a new headache for the aircraft maker as it recovers from the much more severe 737 crisis. MAX. Boeing’s narrow-body flagship aircraft was grounded for nearly two years after two fatal accidents.
The United engine fan blade will be examined Tuesday after being transferred to a Pratt & Whitney laboratory where it will be examined under the supervision of NTSB investigators.
“What is important is that we really understand the facts, circumstances and conditions surrounding this particular event before we can compare it to any other event,” said Sumwalt.
Boeing recommended that airlines suspend use of the planes while the FAA identified an appropriate inspection protocol and Japan imposed a temporary suspension of flights.
The Federal Aviation Administration plans to soon issue an emergency airworthiness directive that will require intensified inspections of the fan blades for fatigue.
The FAA in March 2019 after the February 2018 United engine failure attributed to fan blade fatigue ordered inspections every 6,500 cycles. A cycle is a take off and a landing.
Sumwalt said the United incident was not considered an irrepressible engine failure because the containment ring contained the parts as they flew.
There was minor damage to the body of the aircraft, but no structural damage, he said.
The NTSB will investigate why the engine hood detached from the plane and also why there was a fire despite indications that the engine fuel had been turned off, Sumwalt added.
Pratt & Whitney, which is owned by Raytheon Technologies Corp, said Sunday it was coordinating with regulators to review inspection protocols.
Almost half of the global fleet of 128 aircraft operated by airlines such as United, JAL, ANA Holdings, Korean Air and Asiana Airlines had already been suspended amid a drop in travel demand due to the coronavirus pandemic.
Reporting by David Shepardson in Washington and Jamie Freed in Sydney; Additional reporting on Tracy Rucinski in Chicago Edited by Kim Coghill and Gerry Doyle