Still we dont know, the official version is that the plane was "Lost", however this is weird, and we know that the FARC have been training with some kind of manpad which use mortar granade which could be fire in straight line.
Even when the Farc has .50 them never have been of create enough damage an the planes always was able to return to their bases.
There is not an official answer and statement from the Colombian Air Force about the "accident" of this Super Tucano. the corps of the Pilot of the Aircraft in mention Lt. Andrés Serrano Lemus is in the hands of the military of the Colombian Air Force. But the corps of the Co-Pilot Óscar Castillois in the hands of the FARC. there are press sources that the Farc mined the accident area, thats why the military and other officials cant reach at this time the area of ther accident. The Commander of the Colombian Air Force General Tito Pinilla said that there is not clear why this aircraft went down. http://www.eltiempo.com/colombia/cal...icr_12023974-4
Also the international comittee of the Red Cross have been contacted by the FARC in order to give to the ICRC the body of one of the crew of the accidented aircraft.
The Colombian Air Force said in the last couple of hours that they have the bodies of the pilot and the co-pilot whose aircraft went down and crashed in the mountains of Cauca, Colombia. The Body of the Lt and commander of the aircraft was founded by firefighters of the region and the second body was delivered to the international comittee of the Red Cross by the Farc.