The US aviation authority on Tuesday ordered a more thorough inspection of the engines, which are similar to those of a Boeing 777 aircraft that had suffered a spectacular failure in Denver days earlier.
The incident in which a Pratt & Whitney engine went up in flames shortly after taking off for Honolulu and scattered debris over a suburb of Denver resulted in numerous Boeing 777s being grounded around the world over safety concerns.
“US operators of aircraft that are equipped with certain Pratt & Whitney PW4000 engines (must) have to inspect these engines before continuing their flight,” said the Federal Aviation Administration (FAA).
The regulator announced that it issued the order “due to a fan failure on Saturday on a Boeing 777-200 that had just departed from Denver International Airport.”
Before they can go back to the skies, operators must perform a thermal acoustic image (TAI) inspection of the large titanium fan blades that sit on the front of each motor. TAI technology can detect cracks on the inner surfaces of the hollow fan blades or in areas that are not visible during a visual inspection, “it said in a statement.
Metal fatigue has emerged as the prime suspect of engine failure that did not cause injuries.
Steve Dickson, the FAA chief, had previously stated at a meeting of the City Hall for flight safety on Tuesday: “We want to understand what happened and take the necessary steps to prevent a similar recurrence.”
“We are fortunate that there have been no deaths or injuries,” added Dickson.
The near-miss over Denver was another setback for Boeing, which only recently resumed delivery of the elongated 737 MAX after two fatal accidents.
It also raises new questions about the FAA, which was outright attacked for overseeing Boeing in the certification of the 737 MAX, and whether maintenance on the plane was adequate, aviation professionals said.
Even before the Denver incident, the US aviation safety authorities had weighed up stricter inspections of the jets and their Pratt & Whitney engines, US officials said on Tuesday.
The FAA reviewed the inspection records and maintenance history after an incident involving a Japan Airlines fan blade on December 4 last year “to determine the cause of the breakage and see if the blade inspections should be adjusted,” an FAA spokesman said on Tuesday Tuesday. The flight landed in Japan without injuries.
Following an incident in February 2018 with another United jet, the FAA reviewed 9,000 fan blade inspection reports and issued an airworthiness policy setting new rules for inspections.
– metal fatigue –
In a briefing on Monday, the National Transportation Safety Board said it was too early to know whether the problem in Denver was similar to that on Japan Airlines’ flight or the February 2018 incident involving another Boeing 777 and Pratt & Whitney was involved.
“A preliminary on-site inspection indicates damage related to metal fatigue,” NTSB chairman Robert Sumwalt said of the briefing.
He said two fan blades broke on engine number two on the Boeing 777-200 on Saturday. One of them was later found on a soccer field while the other was stuck in the engine.
The NTSB also plans to review the inspection log on the United plane to see “who knew what, when, what could have been done and what should have been done,” Sumwalt said.
“Fatigue means the material can have a crack, and if you keep loading it the crack will grow slowly,” said Robert Kielb, professor at Duke University’s engineering school.
“This is an example of an event where we learn about the design 20 years after it went live and then immediately ground the fleet, find out what’s going on, and fix it.”
– Headache for Boeing –
After the Denver incident, Boeing said all 128 777s were grounded with Pratt & Whitney engines.
Of the 128 aircraft, only 69 were in use while 59 were in the warehouse.
The airlines affected included United, which put 24 aircraft out of service, the Japanese airlines Japan Airlines and All Nippon as well as the South Korean airlines Asiana and Korean Air.
On Monday evening, a Delta Air Lines flight on a Boeing 757 en route from Atlanta to Seattle to Seattle was diverted from Salt Lake City “out of caution after an indicator pointed to a possible problem with one of its engines,” a Delta said -Speaker said.
“The flight landed safely without incident and rolled to the gate without assistance.”
Boeing only resumed shipments of the 737 MAX after a 20-month global grounding period after 346 people were killed in two accidents.
The MAX returned to commercial service in late 2020, with air travel still depressed due to the coronavirus pandemic.
Boeing executives said last month they expected it would take about three years for activity to return to pre-pandemic levels.
Michel Merluzeau, an expert at consulting firm AIR, agreed that the recent problem did not appear to be due to poor aircraft design.
“It’s not really a problem for Boeing,” he said. “It’s more about maintenance – like United or Pratt & Whitney servicing engines that have been in use for a long time.”
The episode “is an embarrassing headline, but as a practical issue it will have no impact on Boeing,” said Scott Hamilton of Leeham News, an aviation news site.
(Except for the headline, this story was not edited by GossipMantri staff and published from a syndicated feed.)