Human error, a technical malfunction or an incorrect command are the versions on which investigators of the reasons that led to the crash of the L-39 training aircraft in "Graf Ignatievo" work. This is what Major Hristo Anchev, a supervising prosecutor from the Military District Prosecutor's Office Plovdiv, told BNT. According to him, the reason cannot be clarified quickly. 

Investigators expect data from the black box to narrow down the versions, but experts will say whether it can be read. The legal period for an investigation is 2 months, but it can be extended, Major Anchev added. The flight that cost the lives of pilots Major Petko Dimitrov and Senior Lieutenant Ventsislav Dunkin, lasted exactly 13 minutes. They took off on September 13 at 12:17 p.m. Witnesses said the plane plummeted in a straight line, leaving the formation of two other planes.