Fifteen months after a spectacular failure over Denver, the FAA has now cleared United Airlines to return its P&W-engined 777s to service.
The event attracted a lot of attention when it happened, partly because of its location. The aircraft, a United Boeing 777-200, was departing Denver (KDEN) as flight UA328, heading for Honolulu. Its initial climb went fine, but its crew later powered up again, preparing to go over the Rockies. That’s when the aircraft suffered an engine failure, over a residential area. It had climbed past 13,000 feet at the time.
Its crew managed to return for a safe landing back in Denver, but not before it rained engine parts on the town of Broomfield. More correctly, these were engine cowl and inlet parts – more on that later. Some days after the accident, United and other airlines grounded their Boeing 777s with these Pratt & Whitney PW4000-112 engines.
United had suffered another, very similar failure to another 777-200 years earlier. In an interesting twist, the passengers of flight UA328 last year eventually made it to Honolulu in the aircraft that suffered that previous failure! United was one of few airlines still operating these P&W-engined 777s. JAL in Japan suffered another such failure three months earlier. They were going to retire the jets early in 2022. So with an investigation likely to take as long as that, the Japanese airline retired them early.
United Airlines And Its Much-Loved P&W-engined 777s
United had no such plans. Originally, the airline hoped to see these aircraft return to service last summer. This wasn’t possible. The FAA wanted to see improvements in three different areas, to allow these jets back in service. Two of these improvements are related to the engine itself. The other had to do with Boeing’s design of the engine cowling and inlet. Boeing is responsible for integrating these engines into its aircraft. Technically, these were contained failures, because the engine’s own casing retained the high-energy parts. But Boeing’s cowl failed.
As we saw last month, United Airlines was hoping to return these 777s back to service in the second half of May. Fortunately for the airline, this time the deadline did not slip. On Tuesday (May 17th) it announced that the FAA has cleared the aircraft for service. The approval was dependent on the implementation of the appropriate service bulletins, addressing the previous failures. These SBs include both modifications to the jets and engines and more frequent inspections.
The airline will perform its first flights with the jets next week. United Airlines has a total of 52 Boeing 777s with these engines. We have seen that other carriers struggled to ramp up capacity after the pandemic. These jets are vital for United, to meet the rising demand for the coming summer season.
Initially, the airline will return a small number of these aircraft to service. United took advantage of the type’s forced hiatus, by servicing a number of jets and repainting them in its newer colours. These aircraft are some of the oldest Boeing 777s still in service.
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