 The accident was caused by the "milkbone" joining bolt in the main wing which had been weakened by years of flying and failed in-flight.All RF-84F aircraft were immediately grounded after inspections of other F-84Fs in the Air National Guard found the same issue affected many other aircraft.The problem was deemed too widespread to justify the economic repair of the aircraft, and it was decided to retire the ANG's fleet of F-84Fs and replace them with more modern aircraft.