Accident
On an unspecified date, a single-engine airplane operating an on-demand charter flight from Olyokminsk to Shushenskoye with an intermediate stop in Zheleznogorsk-Ilimsky crashed shortly after takeoff. On board were two pilots and three employees of a gold mine company.
After departure from Olyokminsk Airport, while climbing to an altitude of 70 to 100 meters, the crew observed that the exhaust gas temperature was abnormally high, reaching 570°C. The copilot reduced engine power, but the temperature did not decrease. Suddenly, the engine lost power, and as airspeed declined, the aircraft began to descend. The pilot attempted an emergency landing, but the airplane struck trees and crashed in a densely wooded area located 600 meters east of the threshold of runway 26.
The impact destroyed the airplane. One passenger was killed, and the other four occupants sustained injuries.
Investigation
The investigation determined that the loss of engine power resulted from the failure of the exhaust gas temperature regulator (designation RT12-7 IIc). This failure led to a subsequent loss of airspeed, a descent, and the aircraft’s collision with trees and the ground.
The accident was attributed to a combination of factors: violation of the regulator repair procedures; repairs carried out by personnel without specific training; and the captain’s failure to check the proper functioning of the temperature regulator after engine start, as required by the Aircraft Flight Manual.
Probable Cause
Loss of engine power in flight caused by the failure of the exhaust gas temperature regulator (RT12-7 IIc). This led to a subsequent loss of airspeed, a descent, and the aircraft’s collision with trees and the ground. The accident resulted from a combination of the following factors: violation of the regulator repair procedures; repairs of the regulator were carried out by personnel who did not have specific training; the captain failed to check the proper functioning of the temperature regulator after the engine was started, as required by the Aircraft Flight Manual.