The United Airlines Boeing 777-200 planes, powered with Pratt & Whitney engines, may stay grounded until early 2022. Meanwhile, the Federal Aviation Administration (FAA) reportedly considers whether any new requirements should be applied before returning the type to service.

United Airlines had planned to return the Pratt & Whitney engine-powered Boeing 777-200 jets to passenger service by summer 2021. However, the airline has not ungrounded the aircraft yet because the FAA keeps doubting if any new requirements for the plane variant are necessary, industry sources familiar with the matter told the Wall Street Journal on August 30, 2021. 

The aviation authority reportedly considers proposing an additional engine-blade inspection as well as some modifications that should work as a precautionary measure to prevent engine fan blades from breaking and engine covers from tearing off.

United Airlines grounded 24 Boeing 777-200 aircraft with certain Pratt & Whitney PW4000 engines in February 2021. The grounding was the airline’s response to the incident during flight UAL328. A 777-200 jet, operating flight UAL328 from Denver, United States, to Honolulu, Hawaii, United States, suffered an uncontained engine failure, scattering engine parts over several neighborhoods around Denver. 

Following the incident, Boeing requested the grounding of 128 aircraft around the world pending a safety inspection. 

Reacting to the situation, the FAA issued an emergency airworthiness directive (AD) requiring owners and operators of the Pratt & Whitney PW4000-112 engines powering Boeing 777s to immediately perform a thermal acoustic image inspection before any further flight.

United Airlines is the only airline in the United States that used to actively operate the Boeing 777-200 variant before the incident, the Planespotters.com data indicates.