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Debris from the reactor of flight UA328 in Broomfield, a suburb of Denver. (Photo: AFP/Michael Ciaglo/Getty Images)

Engine explosion spurs Boeing 777 groundings in US and Asia

Debris from the reactor of flight UA328 in Broomfield, a suburb of Denver. (Photo: AFP/Michael Ciaglo/Getty Images)

Airlines grounded dozens of older Boeing Co 777 aircraft after the failure of a Pratt & Whitney engine showered debris into a Denver suburb and prompted US regulators to order emergency inspections.

United Airlines Holding Inc halted operations of 24 of its planes in the wake of the incident involving one of its fleet over the weekend. The US Federal Aviation Administration ordered fan-blade checks on PW4077 engines made by Raytheon Technologies Corp.’s Pratt & Whitney division.

United Airlines Holding Inc halted operations of 24 of its older Boeing Co 777 aircraft after the failure of a Pratt & Whitney engine showered debris into a Denver suburb at the weekend. (Photo: Flight Radar)

Airlines in Japan and South Korea also have 777 jets with the engine variant. Japan’s transport ministry grounded the planes early Monday, while Korean Air Lines Co. and Asiana Airlines Inc. said theirs would be idled.

The incident on United Airlines Flight 328 from Denver to Honolulu took place shortly after it took off on Saturday with 231 passengers and 10 crew members on board. The Boeing 777 landed safely back at Denver and nobody was injured by the falling debris. Footage of the burning engine was filmed by a passenger aboard the flight, while people on the ground captured scenes of the plane overhead and scattered aircraft parts near houses.

The scare comes at an extremely sensitive time for the global aviation industry, which has been plunged into crisis by the coronavirus pandemic and its impact on travel. Boeing is only just dusting itself off from the nearly two-year grounding of its best-selling 737 Max jet following fatal crashes in Ethiopia and Indonesia, while Pratt has faced separate issues with its geared turbofan engines on Airbus SE A320neo jets, particularly in India.

Two fan blades were fractured on the United flight, the National Transportation Safety Board said. Most of the destruction was contained to the engine and the plane suffered only minor damage.

Footage of the burning engine was filmed by a passenger aboard the flight, while people on the ground captured scenes of the plane overhead and scattered aircraft parts near houses.

Another blow for Boeing

While the incident doesn’t suggest broader problems with the 777, a twin-engine wide-body plane typically used on intercontinental routes, it adds another urgent issue to Boeing’s to-do list just after the 737 Max was cleared to fly again in markets including the US and Europe. The company also halted deliveries of its 787 Dreamliners to check for manufacturing flaws.

“We recommended suspending operations of the 69 in-service and 59 in-storage 777s powered by Pratt & Whitney 4000-112 engines until the FAA identifies the appropriate inspection protocol,” Boeing said in a statement, adding that it supports decisions by the FAA and Japan’s Civil Aviation Bureau to temporarily ground aircraft powered by the engines.

The European Union Aviation Safety Agency said Monday it was in touch with the FAA about two incidents involving Boeing planes with Pratt & Whitney 4000 family of engines. A 747 cargo plane had to make an emergency landing on Saturday shortly after take-off from Maastricht in the Netherlands, following an uncontained engine failure.

“We are voluntarily & temporarily removing 24 Boeing 777 aircraft powered by Pratt & Whitney 4000 series engines from our schedule. We will continue to work closely with regulators to determine any additional steps and expect only a small number of customers to be inconvenienced.”

While airlines in the US, Japan and South Korea operate 777s with the PW4000 family of engines, United is the only US carrier with that combination. A Japan Airlines Co 777-200 fitted with the engines suffered a similar failure on December 4.

Spokespeople for Japan Airlines and ANA Holdings Inc said Monday they’ve grounded their 777s following the transport ministry’s order and are using other aircraft, while South Korea’s transport ministry said it was looking into the issue.

Korean Air halted all operations of 12 777-200 and four 777-300 jets with PW4000 engines and is in talks with the South Korean government and manufacturer. More than half of those Korean Air planes are already in storage due to the coronavirus pandemic. Asiana has nine 777s with the Pratt engines, mostly sitting unused.

Only 60 Pratt-powered 777-200 and -300 models are still flying globally, according to analysis of Cirium data by George Ferguson at Bloomberg Intelligence. Another 67 of the jets are in storage, although they haven’t officially been retired.

The inspections could hasten the end of the earliest 777 models if the repairs turn out to be costly, Ferguson said. “They are already out of favor because of their size and the pandemic.”

The 777 is distinctive for its hulking turbofans that are about as wide as a 737 jetliner cabin. The PW4000-112 debuted with the first of the 777s in 1995. In 1999, Boeing awarded General Electric Co. an exclusive contract to power newer, longer-ranger versions of the 777 with its GE90 engines and eventually phased out the Pratt offering.

“Pratt has not had any market share in this space for a long time,” Ferguson said. “It’s all GE.”

The crack that led the fan blade to break on the United flight was similar to one that occurred on a 2018 United flight, said a person familiar with the preliminary investigation results who wasn’t authorised to discuss them.

In the latest failure, one fan blade cracked and broke off near where it attached to a rotating hub, according to the person. A second blade was also broken, apparently after it was struck by the first blade.

Corrective measures

“We are voluntarily & temporarily removing 24 Boeing 777 aircraft powered by Pratt & Whitney 4000 series engines from our schedule. We will continue to work closely with regulators to determine any additional steps and expect only a small number of customers to be inconvenienced.”

The blades on this type of PW4000 are hollow and made of titanium. The cracks appear to start from within the surface, making them hard to detect. Airlines can use technologies such as ultrasound to find them beneath the surface. The blades are only used on some 777 planes, said the FAA, which is stepping up the frequency of inspections.

Pratt has dispatched a team to work with investigators and is coordinating with airlines and regulators. “Any further investigative updates regarding this event will be at the discretion of the NTSB,” the company said in a statement.

The exact details of what type of inspections will be needed and how quickly they must be done are still being worked out, FAA Administrator Steven Dickson said in an emailed statement.

Earlier: United Plane Showers Debris Near Denver After Engine Failure

United has 52 of the planes in its fleet. Of those, 28 are in storage. The airline will work closely with the NTSB and FAA “to determine any additional steps that are needed” to return the aircraft to service, it said in an emailed statement.

Other failures

A flaw in a fan blade on a United 777 in 2018 was blamed by the NTSB on inadequate test standards at Pratt. An inspector had seen a possible sign of a crack years before the failure, but attributed it to paint, the NTSB said.

The company said last June that it had taken corrective actions to address the cause of the failure. After the 2018 incident, Pratt re-inspected all 9,600 fan blades and didn’t find any others with potential safety problems, the NTSB said.

Separately, Dutch investigators are looking into the other engine failure that occurred on Saturday, when a Boeing 747-400 cargo plane shed engine parts after taking off from Maastricht. The Pratt model was a PW4056, which is from the same range as the PW4077.

“These recent incidents on the 777 and a 747 do suggest a closer look needs to be taken at the older PW4000 engines and their inspections and maintenance,” said Sanjiv Kapoor, a former top executive at SpiceJet Ltd. and Vistara, the Indian affiliate of Singapore Airlines.

More: ‘Sheer Panic’ Grips Cabin in First Fatal U.S. Flight Since 2009(Adds Asiana grounding from third paragraph)

–With assistance from Ryan Beene, Angus Whitley, Kyunghee Park, Tsuyoshi Inajima, Katrina Nicholas and Anurag Kotoky.