What happened
On the night of May 6, 1969, a Douglas DC-6 A/B, registration HB-IBT, operating on behalf of the International Committee of the Red Cross (ICRC), crashed approximately 10 km north of the Uli airfield in Biafra. The aircraft was performing a supply flight from Cotonou as part of a humanitarian airlift. During the final approach, the aircraft struck tall palm trees, causing significant structural damage and an immediate post-impact fire. The impact destroyed the airframe, and the aircraft burned completely. All four occupants—the pilot, co-pilot, flight engineer, and loadmaster—were killed.
The investigation
The investigation examined the extreme operational environment of the Biafran airlift, characterized by wartime conditions. The investigation established that the aircraft was well-maintained and that the crew was highly qualified, with the captain being an experienced pilot on the route. The investigation also reviewed the specific approach procedures used at Uli, where runway and approach lighting were intentionally kept extinguished until the final moments of an approach to avoid attracting enemy fire. The investigation noted that the flight was part of a high-pressure operation where crews often flew multiple night sorties per night under intense physical and psychological strain.
Findings
- The crew elected to perform a direct approach to the unlit runway, bypassing the standard prescribed approach procedure.
- This direct approach likely led to a significant error in distance estimation; the crew believed they were on short final while still approximately 10 km from the runway.
- The extreme operational pressures, including the need to minimize time on the ground to avoid air attacks and the physical exhaustion from high duty periods, contributed to the error.
- The lack of visual references due to the unlit airfield and the use of a non-standard approach made it impossible for the crew to accurately judge their position relative to the runway.
Safety action
No specific safety recommendations were recorded in the final report, though the investigation highlighted the extreme risks inherent in the wartime flight conditions and the high duty loads placed on the crews.