The official US Air Forceaccident investigation board report noted several reasons that led the Boeing CT-43A, callsign "IFO-21", to crash. Chief among the findings was a "failure of command, aircrew error and an improperly designed instrument approach procedure". The inclement weather was not deemed a substantial contributing factor in the crash. The Boeing CT-43A used for this flight was formerly a T-43A navigator training aircraft that was converted for distinguished visitor travel. The flight was on an instrument flight rulesnon-directional beacon approach, which is a non-precision type of instrument approach, to Runway 12 when it strayed off course. Non-precision approaches are those that do not incorporate vertical guidance. While NDB approaches are essentially obsolete in the United States, they are still used widely in other parts of the world. Because of their infrequent use in the United States, many American pilots are not fully proficient in performing them. The investigation board determined that the approach used was not approved for Department of Defense aircraft, and should not have been used by the aircraft crew. The board determined that the particular NDB approach used required two operating ADFs, the instrument used to fly such an approach, on board the aircraft, but this aircraft only had one ADF installed. To successfully fly the approach, one ADF was required to track the outbound course of 119° from the Koločep NDB, while another ADF was required to observe when the aircraft had flown beyond the Cavtat NDB, which marked the missed approach point. The alternative available to the crew was to repeatedly switch their one ADF between the signals at the KLP and CV beacons, though this would add further workload and stress to the crew. Further, the board noted that the approach was rushed, with the aircraft flying at above the proper final approach speed and had not received the proper landing clearance from the control tower. The crash site, on a hill, was northeast of where the aircraft should have been on the inbound course to the NDB. The published NDB approach brings the inbound aircraft down a valley, and has a minimum descent height of at the missed approach point, which is below the elevation of the hills to the north. The runway is at MSL. Five other aircraft had landed prior to the CT-43A and had not experienced any problems with the navigational aids. There was no emergency call from the pilots, and they did not initiate a missed approach, even though they were beyond the missed approach point when they hit the hill at 2:57 PM local time. Each country is responsible for publishing the approach charts, including minimum descent heights, for its airports, and the investigators noted that the minimum in mountainous terrain in the United States is, as compared to the on the chart given to the crew of IFO-21. It was a requirement of the US Air Force to review and approve all charts, and to ban flights into airports for which the charts did not meet the proper American aviation standards. The commander of the 86th Operations Group, Col. John E. Mazurowski, revealed that he had requested approval to waive the review for Dubrovnik, as the approach had worked for years and the delay of a full review could hamper the interests of the American diplomatic mission.
Outcomes
Dubrovnik Airport was singled out for an improperly designed approach and landing procedure. A number of US Air Force officers were found to have contributed to a failure of command. The general commanding the 86th Airlift Wing, Brig. Gen. William E. Stevens, vice-commander Col. Roger W. Hansen and the commander of the 86th Operations Group, Col. John E. Mazurowski, were all relieved of their posts. Mazurowski was later found guilty of a dereliction of duties and was demoted to major, while twelve other officers were reprimanded. The USAF ordered all military aircraft to be equipped with a flight data recorder and a cockpit voice recorder. American military aircraft are no longer allowed to fly into airports without explicit approval from the United States Department of Defense, not even for high ranking diplomatic missions.
Legacy
The area of the crash site is identified by a large stainless steel cross on Stražišće peak. Hikers can reach the peak via the "Ronald Brown Path", which is named in commemoration of the U.S. Secretary of Commerce who died in the crash. A memorial room has been installed in the Ronald Brown memorial house in the old city of Dubrovnik. It features portraits of the crash victims as well as a guest book. The head of navigation at Čilipi Airport, Niko Jerkuić, was found dead three days after the accident with a bullet wound to his chest. The police investigation concluded that the case was a suicide.
In popular culture
The crash of IFO-21 was covered in "Fog of War", a Season 4 episode of the internationally syndicated Canadian TV documentary series Mayday.
