Colombian investigators believe a Douglas DC-3 crew’s failure to verify minimum safe altitudes during an unscheduled commercial domestic flight led to a fatal collision with high terrain.

Neither the two crew members nor the three other occupants of the Aerolineas Andinas aircraft (HK-4700) survived after it struck a mountain at an altitude of 6,500ft.

It had been operating a flight between Villavicencio, near Bogota, and Florencia, in southern Colombia, on 8 May 2014.

Colombia’s Grupo de Investigacion de Accidentes e Incidentes Aereos attributes the crash to a failure to assess hazards while planning for the visual flight.

It had been received 1,050kg of fuel at Villavicencio, plus 2,540kg of cargo, giving the aircraft a take-off weight of 11,430kg. It departed the airport at 11:15 without any record of take-off clearance, the inquiry says, or a response from the crew.

The crew had planned to fly a track to La Uribe, then San Vicente del Caguan, and on to Florencia. Satellite images showed cloud cover en route but adequate visibility at San Vicente and Florencia.

Previous flights on the route had been carried out at a cruising altitude of 8,500ft. The inquiry says that, despite having GPS and weather radar capability, which could “guarantee” flight at safe altitude, the flight continued to operate at 6,500ft in adverse weather rather than divert or return to its departure point.

GPS equipment recovered from the crash site showed the aircraft had deviated from the straight-line course. The DC-3, which was built in 1944, had been flying at a ground speed of 136kt and recorded information showed an altitude of 6,726ft before the collision in a national park on the border between the Meta and Caqueta departments.

Investigators state that controlled flight into terrain tends to be the result of losing situational awareness, particularly in reduced visibility due to weather conditions, and under self-imposed pressures to complete a flight.

Both pilots were highly experienced, with the captain having almost 10,000h on type. But the inquiry says there is no record of the crew’s being trained in strategies to prevent controlled flight into terrain.

Source: Cirium Dashboard