A point to remember about Colombia is the elevation of most of their airports. Villavicencio is at 1394ft - not particularly high as they go. Pasto is 5950 ft, Bucaramanga 3902 ft. Pereira is at 4818 ft, and they are the smaller airports such as the DC-3s use. Even the 'lower' airports such as Mitú are at 680 ft, (same as LBA), and the one thing they have in common is that they are all close to the Equator.
Surely the 'hot and high' combination is anathema to 70-80 year old piston engines. The loss of an engine on take-off on a DC-3 at those altitudes, especially if they have cargo on board, can only lead to one thing.