CHICAGO—United Airlines said on Wednesday its Boeing 777-200 planes equipped with Pratt & Whitney (PW) engines are expected to return to service as early as in the first quarter of 2022. The Chicago-based carrier had to ground the wide-body jets after a United flight to Honolulu suffered an engine failure and made an emergency landing in February in Denver. The U.S. Federal Aviation Administration (FAA) ordered immediate inspections of Boeing 777 planes fitted with Pratt & Whitney PW4000 engines after the incident. On Wednesday, the regulator said it is still evaluating the manufacturers’ proposed fixes and will not approve them until it is satisfied that they address its safety concerns. “Any work performed on the airplanes prior to that time is subject to being affected by any new Airworthiness Directives,” the FAA said in a statement. Greg Hart, United’s executive vice president, strategy and planning, said the company has not …