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United, Japan Suspend Operations of PW4000 Boeing 777s

A United 777-200 departs from Washington-Dulles (Photo: AirlineGeeks | Ben Suskind)

Through a Notice to Airmen released Sunday, the Japanese aeronautical authority reported that it had decided to prohibit the operations of Boeing 777s with Pratt & Whitney 4000 engines until further notice. This prevents the operation of 32 aircraft owned by Japan Airlines and All Nippon Airways as well as the overflight and takeoff or landing in Japanese territory by all aircraft with the engines.

The measure, taken by Japan’s Ministry of Lands, Infrastructure, Transport and Tourism affects 13 aircraft operated by Japan Airlines and 19 operated by All Nippon Airways, a subsidiary of ANA Holdings. JAL and ANA had already suspended the operations of these planes before the ministry’s instructions. As a result, a JAL flight to Haneda from Naha was canceled.

This is not the first time that the Pratt & Whitney 4000 family has been in the sights of the Japanese authority: in December 2020, a JAL Boeing 777 equipped with the same PW4000 engines suffered uncontained engine failure, prompting inspections to become more stringent for aircraft operating with the engine variant.

The decision comes after a United Airlines flight from Denver to Honolulu was forced to make an emergency landing on Saturday. The NTSB indicated that an investigation had begun.

For its part, the FAA indicated that it will issue an Airworthiness Directive to carry out “immediate or stepped-up” reviews of Boeing 777s equipped with PW4000 engines. The authority indicated that this most likely would require removing some aircraft from service.

The FAA says it received all available information about yesterday’s incident and concluded that the engine blade inspection interval should be reviewed. He also reported that it is working with Boeing and the engine manufacturer to prepare the Service Bulletins in which the work to be carried out in the inspections will be described.

In a statement released on Sunday evening, United Airlines declared that is “voluntarily & temporarily removing 24 Boeing 777 aircraft powered by Pratt & Whitney 4000 series engines from our schedule.” The airline states that it “will continue to work closely with regulators to determine any additional steps and expect only a small number of customers to be inconvenienced.”

The Pratt & Whitney 4000 series is a widely-used engine that equips aircraft beyond simply the 777. It is used by Airbus A300/A310, A330, Boeing 747-400 and 767 and McDonnell Douglas MD-11. Due to a unique blade configuration, the issue that is prompting regulators to take these actions is limited only to 777s with PW4000s rather than extending to the other types.

The NTSB confirmed that its initial examination revealed that two blades failed aboard United’s flight 328, causing the uncontained failure. One of the blades fractured near its root, and an adjacent fan blade was fractured near mid-span. Additionally, remaining fan blades experienced damage on the leading edges and the tips.

The board will continue the revision of evidence and testimonies in a separate procedure, not affecting the release of an Airworthiness Directive.

Pablo Diaz


  • Pablo Diaz

    Since a little kid, Pablo set his passions in order: aviation, soccer, and everything else. He has traveled to various destinations throughout South America, Asia, and Europe. Technology and systems expert, occasional spotter, not-so-dynamic midfielder, blogger, husband, father of three cats; he believes that Latin America's aviation industry past, present, and future offer a lot of stories to be told.

    View all posts

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