Accident Overview
On 20 March 2015, at 13:01 local time (18:01 UTC), a Cessna TU206G, registration HK2327, crashed into the Vaupés River near Puerto Corroncho, Mitú, Vaupés, Colombia, following an engine power loss. The aircraft was operated by Aerolíneas Llaneras - ARALL LTDA on a non-scheduled passenger flight (air taxi) from Mitú (SKMU) to San José de Cananarí (9AK). There were one pilot and three passengers on board.
Sequence of Events
The flight originated earlier that day from Villavicencio (SKVV) to Mitú, arriving without incident. After refueling, the pilot filed a VFR flight plan for the 30-minute leg to San José de Cananarí. The aircraft departed Mitú at 12:46 local time. During initial climb, performance was normal at approximately 100 ft/min. About 10 nautical miles from Mitú at 2,800 feet, the pilot observed fluctuations in the manifold pressure gauge. He requested return to Mitú at 12:56 local time. Pressure momentarily normalized but then dropped to 18 inches. The aircraft began losing altitude at 100 ft/min despite the pilot's attempts to regain power. At 12:57 local time, the pilot radioed that he was at 2,000 feet near a river bend. Unable to maintain altitude, he elected to ditch in the Vaupés River. At 13:01 local time, with flaps set and airspeed 75 knots, he reduced power and impacted the river surface.
Injuries and Damage
Upon impact, the aircraft rapidly submerged. The pilot and one passenger evacuated the aircraft and sustained minor injuries. The two remaining passengers did not escape and sustained fatal injuries. The aircraft was partially damaged, including separation of the cargo pod, dents in the forward ventral section, broken forward plexiglass, and general deformation of the right side.
Aircraft and Engine Information
The Cessna TU206G, serial number CU-20605102, had a total of 3,192.34 flight hours. It was equipped with a Continental TSIO-520-M engine (serial 520723) and a McCauley propeller. The engine had undergone a major overhaul on 9 June 2014, accumulating 435.15 hours since overhaul. The last 100-hour inspection was performed on 3 March 2015. Weight and balance calculations showed takeoff weight of 3,260 lbs, within the maximum of 3,600 lbs.
Investigation
The investigation by the Colombian aviation authority (GRIAA) determined contributing factors: engine power loss due to turbocharger malfunction from ingestion of fragments of an exhaust valve guide; operation of the engine under prolonged lean mixture regimes; and deficiencies in the execution of cabin safety procedures during pre-flight and emergency phases. The National Transportation Safety Board (NTSB) participated as the state of manufacture. Meteorological conditions at the time (visual meteorological conditions) were not causal.