Bulgaria's Ministry of Defense's commission investigating the September 13 aviation accident at Graf Ignatievo Airbase, which resulted in the deaths of Lieutenant Colonel Petko Dimitrov and Captain Vencislav Dunkin, concluded that the pilots took an unreasonably high risk. The accident occurred during a training flight involving an L-39 combat training aircraft as part of an air show marking the 20th anniversary of Bulgaria’s accession to NATO.

The commission’s report detailed that complications arose when the aircraft attempted to maneuver parallel to the runway, reducing its speed below the necessary level for performing a vertical maneuver. At 12:30:01, the crew initiated a climb with a G-force of 3.6 and a slight right bank. At that point, the aircraft was at an altitude of 68 meters and traveling at a speed of 455 km/h. The commission noted that this climb initiated a series of events leading to a complex situation.

By 12:30:13, the aircraft had reached an altitude of 647.61 meters but had decelerated to 213 km/h. The crew then initiated a descent with a steep pitch angle that deepened into an emergency situation. The commission observed that, within a second, the pitch angle worsened, creating conditions for a successful ejection between 12:30:17. However, since the crew did not attempt to eject, the situation escalated to catastrophic proportions. The immediate cause of the crash was the impact of the aircraft with the ground. The main factor was determined to be the decision to take a high-risk maneuver, compounded by a failure to follow safety protocols and an incorrect assessment of altitude during the maneuver.

Colonel Petko Vasilev, an expert from the Military Police’s “Investigation of Aviation Accidents and Incidents” department, explained that the commission identified additional contributing factors, including the violation of safety measures, improper execution of the flight task, and misjudgment of altitude. The report suggested that the aircraft was controllable and could have been recovered differently before the situation became catastrophic.

Defense Minister Atanas Zapryanov expressed his concern over the incident, emphasizing that such losses of life in peacetime are unacceptable. He stated that while personnel decisions will be considered, they will only occur after all information is reviewed. Zapryanov assured that those who fail to follow regulations or uphold their duties will be held accountable.

Zapryanov stressed that the commission's investigation is independent of judicial and pre-trial inquiries. He highlighted the importance of maintaining transparency and accuracy in determining the cause of the accident, stating that human lives are of utmost value to the Ministry of Defense. He reiterated that such incidents must be minimized, especially in peacetime.

Colonel Vasilev provided further insights into the commission's four focal areas of investigation: evaluating the crew's flight training and organization of the flight, conducting a medical examination, assessing the aircraft's technical condition, and analyzing the circumstances of the crash. He noted that, on September 9, 2024, a preliminary briefing was held via video conference to review safety protocols for the open flying day event at Graf Ignatievo.

Investigators are currently exploring three main theories for the cause of the crash: pilot error, a technical malfunction, or an incorrect command. The aircraft’s black box was sent to the Czech Republic for analysis, revealing that the plane was flying at an insufficient altitude during the maneuver.