The Federal Aviation Administration (FAA) is looking into a possible violation of aircraft separation standards during the Notre Dame Stadium flyover Saturday, a report from WNDU said.

A Cessna Citation aircraft was beginning to land at the South Bend airport at around 7:30 p.m. on Saturday when the four F-15s “came in for a flyover” for the Notre Dame-Michigan football game, the report states.

Officials are working to determine the exact distance between the aircraft for an investigation that could last multiple weeks, the report said.