WASHINGTON—The Federal Aviation Administration (FAA) said on Wednesday it is finalizing three safety directives for some grounded Boeing 777 planes with Pratt & Whitney 4000 engines that will allow them to return to service. The new final airworthiness directives cover Boeing 777s like a United Airlines 777 that failed shortly after takeoff from Denver in February 2021, showering debris over nearby cities. No one was injured and the plane safely returned to the airport. The FAA said the new directives, which were proposed in December after three reported in-flight fan blade failures, require enhanced inspections and modifications that will allow Boeing 777-200 and -300 airplanes equipped with those Pratt & Whitney (PW) engines to resume flights after being grounded for more than a year. One directive requires installing debris shields on the thrust reverser inner wall, inspecting fan cowl doors for moisture ingression, and repetitive checks of the hydraulic pump …