United Airlines (UA, Chicago O'Hare) has been cleared by the US Federal Aviation Administration to restart operations of its Pratt & Whitney PW4000-powered B777s, more than a year after they were grounded over engine safety concerns.

Chief Commercial Officer Andrew Nocella said at a Bank of America industry conference that the regulator issued a safety bulletin to the airline on May 16, 2022. He predicted that the first aircraft would be back in service in "around a week" from that day.

United Airlines operates fifty-two B777s powered by PW4000 Family engines, comprising nineteen B777-200s and thirty-three B777-200ERs. All of them were grounded in February 2021, after an uncontained engine failure caused an emergency landing of a B777-200 shortly after take-off from Denver International. The airline hoped to start reactivating the B777s this month, but the delayed FAA approval caused it to adjust its schedule to June.

United Airlines never wavered in its commitment to its PW4000-powered B777s, in contrast to JAL - Japan Airlines, ANA - All Nippon Airways, Asiana Airlines, and Korean Air, which all retired or reduced their respective fleets of aircraft powered by this engine family after the grounding.