美国一飞往日本东京的客机因发动机故障紧急折返

Group 1 - A United Airlines flight to Tokyo was forced to return to Washington Dulles International Airport due to an engine failure, with no injuries reported among the 275 passengers and 15 crew members on board [1][4]. - The aircraft involved was a Boeing 777-200ER, and the incident occurred during takeoff when a part of the engine cover detached and caught fire, leading to a fire in the airport's ground brush [4]. - Smoke was observed near the runway at Dulles Airport, but the fire was subsequently extinguished according to the Metropolitan Washington Airports Authority [4].