Two U.S. airliners were found to be missing the same landing gear piece after landing this week at Narita airport near Tokyo, according to separate announcements by the airlines.On Saturday, a 30-centimeter-long spring was found missing from the landing gear of a United Airlines plane that landed at Narita, the U.S. airline said.On Tuesday, the same type of spring was missing from an American Airlines aircraft that landed at the airport, according to the airline.The spring is believed to have come off the United Airlines' plane during the flight of the Boeing 777 aircraft from Houston, Unit…READ FULL ARTICLE