Ан-2 RA-17890 06.08.2014

     The accident with An-2 RA-17890 aircraft owned by "Yug-Line" LLC occurred near Prototskoye landing site, Krasnoarmeysky District, Krasnodar Territory (RF) on August 6, 2014. According to the available information two crew members on board didn't suffer, the aircraft was destroyed and burnt down.
     The Interstate Aviation Committee has formed the Investigation team of the accident in accordance with the Russian Aviation Legislation. The Investigation team started its work.
     

     The Investigation team of the Interstate Aviation Committee has completed the investigation of the accident with An-2 RA-17890 aircraft owned by "Yug-Line" Airlines, LLC occurred in Krasnodar Territory (RF) on August 6, 2014.
      The accident with An-2 RA-17890 aircraft was caused by its nosing-over during the emergency landing at the submerged rice bay.
      The emergency landing was due to the engine power loss in flight caused by the destruction of the can type combustor of the exhaust collector and burnout of the carburetor intake valve with the following high-temperature gases ingestion in the intake areas of the engine carburetor.
      The fatigue destruction of the can type combustor of the exhaust collector was caused along the main crack near the intake flex socket, it started from the surface of the damaged inlet port under the tube attachment pin towards the exhaust collector. By the moment of the main crack formation both inlet ports in left can type combustor under the tube attachment pin towards the exhaust collector had intolerable damage and size. During the last overhaul of the engine exhaust system of An-2 RA-17890 aircraft the left can type combustor had intolerable damage in its attaching lug to the exhaust collector which wasn't eliminated.
      The destruction of the inlet port valve was caused by the fusion of the boundaries of it material grains in conditions of acute temperature exposure induced by the destruction of the left can type combustor wall towards the main crack. Inadequate material (aluminum alloy D-16) of the valve specified by the drawing of aluminum allow AL-9T contributed to the valve destruction.     
      The appropriate safety recommendations based on the investigation results were developed.