What happened
During a local night training session at Douala Airport, the crew was conducting various maneuvers using alternating departures from runways 12 and 3-0. Following several afternoon exercises, the crew initiated a takeoff from runway 12. Shortly after liftoff, the Douglas DC-4 struggled to maintain sufficient altitude. Approximately 1,200 meters beyond the end of the runway, the propeller on the second engine made contact with a tree.
The aircraft continued its low-altitude flight path and collided with a second tree, which ruptured a fuel tank and ignited a fire. During the sequence of events, the propellers for engines one, two, and four became detached from the aircraft. The plane subsequently crashed 200 meters further along the flight path in a large explosion. All five crew members on board were killed in the accident.
Findings
The investigation concluded that the primary cause was flying at an excessively low altitude during the night training exercise. Evidence suggested that the instructor had instructed the pilot to maintain a circling altitude of only 150 feet, a practice that continued into the night operations. It is believed that the aircraft's flaps were being retracted during the climb; if this retraction occurred at low speeds, it would have caused the nose to pitch down.
Given the performance characteristics of the Douglas DC-4, particularly with one engine at reduced power, the flight path was insufficient to clear the nearby treeline. The investigation also noted that the instructor's lack of judgment and a potential lack of seriousness regarding safety margins were critical factors. Additionally, pilot fatigue following a two-hour low-altitude training session may have contributed to the outcome.