|Date||April 3, 1996|
|Summary||Controlled flight into terrain due to pilot error and poorly designed instrument approach|
|Site||3 km (1.9 mi) north of Dubrovnik Airport, Dubrovnik, Croatia.|
|Aircraft type||Boeing CT-43A|
|Operator||United States Air Force|
|Flight origin||Zagreb International Airport, Zagreb, Croatia|
|Stopover||Tuzla International Airport, Tuzla, Bosnia-Herzegovina|
|Destination||Dubrovnik Airport, Dubrovnik, Croatia|
|Fatalities||35 (initially 34)|
|Survivors||0 (initially 1, died shortly after rescue)|
On April 3, 1996, a United States Air Force Boeing CT-43A (Flight IFO-21) crashed on approach to Dubrovnik, Croatia, while on an official trade mission. The aircraft, a Boeing 737-200 originally built as T-43A navigational trainer and later converted into a CT-43A executive transport aircraft, was carrying United States Secretary of Commerce Ron Brown and 34 other people, including The New York Times Frankfurt bureau chief Nathaniel C. Nash. While attempting an instrument approach to Dubrovnik Airport, the airplane crashed into a mountainside. An Air Force Technical Sergeant survived the initial impact, but died en route to a hospital. Everyone else on board died at the scene of the crash.
The aircraft was operated by the 76th Airlift Squadron of the 86th Airlift Wing, based at Ramstein Air Base in Germany. Unlike civilian 737s, the military CT-43A version was not equipped with a flight data recorder nor a cockpit voice recorder.
The official US Air Force accident investigation board report noted several reasons that led the Boeing CT-43A, callsign "IFO-21" (short for Implementation Force), 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 rules non-directional beacon (NDB) 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 (a NASA survey showed that 60% of American transport-rated pilots had not flown an NDB approach in the last year). 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 (KLP), while another ADF was required to observe when the aircraft had flown beyond the Cavtat NDB (CV), 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 80 knots (150 km/h) above the proper final approach speed and had not received the proper landing clearance from the control tower.
The crash site, on a 2,300 ft (700 m) hill, was 1.6 miles (2.6 km) 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 2,150 ft (660 m) at the missed approach point (where they should have climbed and turned to the right if the runway was not in view), which is below the elevation of the hills to the north. The runway is at 510 ft (160 m) 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 2,800 ft (850 m), as compared to the 2,150 ft (660 m) 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 (but not yet received) 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.
Dubrovnik Airport was singled out for an improperly designed approach and landing procedure.
A number of US Air Force (USAF) 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 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
- "List of crash victims". CNN. April 4, 1996.
- "Najpotresnije zrakoplovne nesreće u hrvatskoj povijesti". Index.hr. August 22, 2008.
- Hughes, David "USAF, NTSB, Croatia Probe 737 Crash", Aviation Week & Space Technology, 8 April 1996
- Transcript of US Department of Defense News briefing held on 7 June 2006 "Results of the Accident Investigation Report of the CT-43 Accident". Retrieved: 29 November 2008
- Walters, James M.; Sumwalt, Robert L. III (2000). Aircraft Accident Analysis: Final Reports. McGraw Hill.
- "The weather at the time of the approach was reported as 400 feet broken, 2,000 feet overcast, 8 km or about 5 miles visibility, rain, surface winds for 120, 12 knots, because of the weather, the crew is required to fly an instrument approach procedure into Dubrovnik." Transcript of US Department of Defense News briefing held on 7 June 2006 "Results of the Accident Investigation Report of the CT-43 Accident". Retrieved: 29 November 2008
- FSF ALAR Briefing Note 7.2 - Constant Angle Nonprecision Approach Flight Safety Foundation
- DoD news release Archived September 29, 2007, at the Wayback Machine
- "Fog of War". Mayday. Season 4. Episode 8. Cineflix. 2007-06-03. Discovery Channel Canada.
- "Press Briefing". United States Department of Defense. 1996-05-31. Retrieved 2020-04-22.
- Shenon, Philip (1996-05-31). "Air Force Ousts 3 From Duties In Brown Case". The New York Times. Retrieved 2020-04-22.
- Dubrovnik Online website Archived 2014-03-12 at the Wayback Machine Retrieved: 17 October 2009
- "Ronald Brown memorial house". Retrieved 3 April 2014.
- "Avionom je, ipak, najsigurnije (By plane, However, Is The Safest)". Slobodna Dalmacija. 9 September 2008. Archived from the original on 2008-09-09.CS1 maint: bot: original URL status unknown (link)