NTSB investigators concluded that the likely cause of the crash was that Clay and Polehinke ignored clues that they were on the wrong runway, failed to confirm their position on the runway and talked too much, in violation of "sterile cockpit" procedures. Comair later accepted responsibility for the crash, but also placed blame on the airport, for what it called poor runway signs and markings, and the Federal Aviation Administration, which had only one air traffic controller on duty, contrary to a memo it had previously issued to have two workers on overnight shifts. A judge ruled that, since it was owned by county governments, the airport had sovereign immunity and could not be sued by Comair.