WASHINGTON (Reuters) -The Federal Aviation Administration said on Sunday that a new telecommunications issue at the facility that guides aircraft at Newark Liberty International Airport forced the agency to briefly slow aircraft in and out of the airport. The Philadelphia Terminal Radar Approach Control suffered a new problem that briefly led the FAA to issue a ground stop while it ensured redundancies were working as designed. On Friday, the Philadelphia facility suffered a 90-second radar and telecommunications outage, the second in two weeks after a serious outage on April 28.