WASHINGTON, Dec 13 (Reuters) - Six former chairs of the U.S. Federal Communications Commission (FCC) on Monday urged the Biden administration to quickly resolve a dispute over the planned use of 5G wireless spectrum that the aviation industry says poses an air safety risk. Former FCC chairs Ajit Pai, Tom Wheeler, Julius Genachowski, Michael Copps, Michael Powell and Mignon Clyburn said in a joint letter they were concerned about the Federal Aviation Administration’s (FAA) recent efforts to revisit the FCC’s 2020 decision to allow use of the C-Band spectrum. The former officials said the agencies should work to "resolve the FAA’s concerns expeditiously, but this debate should not be fought publicly in a way that undermines consumer confidence in the process."