(Add details of South Korea inspections)
By David Shepardson and Jamie Freed
WASHINGTON, Feb. 22 (Reuters) – Damage to a fan blade on a car that failed on a United Airlines Boeing 777 flight consists of metal fatigue, based on a preliminary assessment, the U.S. president said. investigators for air accidents said.
The Pratt & Whitney PW4000 engine failed with a “hard blow” on Saturday four minutes after the takeoff from Denver, Robert Sumwalt, chairman of the National Transportation Safety (NTSB), told reporters after an initial analysis of the flight data recorder and voice recorder.
According to him, there is minor damage to the aircraft, but non-structural damage.
He said it remains unclear whether the incident is consistent with an engine outage on another Hawaii-bound United flight in February 2018 attributed to a tired break in a fan blade.
“What’s important is that we really understand the facts, circumstances and conditions surrounding this particular event before we can compare it to any other event,” Sumwalt said.
The engine that crashed on the 26-year-old Boeing Co777 and shook parts over a suburb of Denver was a PW4000 used on 128 aircraft, or less than 10% of the global fleet of more than 1,600,777 wide-body aircraft. which was delivered.
In another incident on Japan Airlines (JAL) 777 with a PW4000 engine in December 2020, Japan’s Transport SafetyBoard reported that two damaged fan blades were found, one with a metal fatigue tear. An investigation is underway.
The focus is more on engine manufacturer Pratt and analysts expect a slight financial impact on Boeing, but the PW4000 issues are a new headache for the planner as it recovers from the severe 737 MAX crisis in the country. Boeing’s flagship narrow-gauge aircraft was on the ground for almost two years after two fatal accidents.
The United engine’s fan blade will be examined on Tuesday after being flown to a Pratt laboratory, where it will be examined under the supervision of NTSB investigators.
The US Federal Aviation Administration (FAA) said on Monday that it had already evaluated whether the fan blade inspections would be adjusted after the incident in December in Japan after checking the maintenance records and performing the metallurgical examination of the fan blade fragment.
Boeing recommended that airlines suspend the use of the aircraft while the FAA identified an appropriate inspection protocol, and Japan imposed a temporary suspension on flights.
Pratt & Whitney, which is owned by Raytheon Technologies Corp., recommended that airlines increase inspections in a plan being reviewed by the FAA, sources with knowledge said. Pratt did not immediately respond to a request for comment.
The FAA said it plans to issue an emergency direction guideline soon that will require intensified inspections of the fan blades for fatigue.
“United Airlines has grounded all the aircraft affected by these engines, and I understand that the FAA is also working very fast, as well as that Pratt & Whitney has repeated or repeated a service bulletin,” Sumwalt said. “It looks like action is being taken.”
In March 2019, after the United engine failure in 2018 was attributed to fan blade fatigue, the FAA ordered about 6,500 cycles. A cycle is one takeoff and landing.
The South Korean Ministry of Transportation said on Tuesday it had instructed its airlines to inspect the fan blades every 1,000 cycles, following Pratt’s guidance following the incident in the United States.
Sumwalt said the United incident was not considered an unintentional engine outage because the parts contained the parts while flying out.
NTSB will investigate why the hood separated from the aircraft and also why there was a fire despite indications that the engine was switched off, Sumwalt added.
Sources in the industry said that although the engine is manufactured by Pratt, the casing or casing is manufactured by Boeing. Boeing referred questions to the NTSB.
Nearly half of the global fleet of PW4000-equipped Boeing777 aircraft operated by airlines, including United, JAL, ANAHoldings, Korean Air and Asiana Airlines, have already been grounded amid a dive into trawling due to the coronavirus pandemic. (Report by David Shepardson in Washington and Jamie Freed in Sydney; additional reporting by Tracy Rucinski in Chicago, Joyce Lee in Seoul and Tim Hepher in Paris; Edited by Kim Coghill and Gerry Doyle)