The An-12 had delivered cargo at Chelyabinsk (CEK) and was heading back to Perm (PEE). The airplane took off from runway 09 at 14:03 UTC. About a minute after takeoff the crew reported smoke in the cockpit. They requested permission to return for landing on runway 09. While positioning for an approach to runway 09 smoke continued to fill the flight deck. The crew also received several (false) warnings. Then two engines automatically shut down. Aileron control was lost about 11 km before landing. The aircraft struck terrain and burned. CONCLUSION (translation from Russian) The aviation accident involving An-12 RA-12957 was the result of a collision with the ground, which was the result of loss of aircraft roll controllability due to the destruction ailerons control cables while carrying out an emergency approach to the airport of departure Chelyabinsk because of the haze cargo cabin. The destruction of aileron wiring occurred, presumably, in the area of the 23-25 web frames of the cargo hold. The reason for the destruction of the wiring installation has most likely been a significant heating of a control rod located in this zone, made of alloy D16-T, and its subsequent break under tension-load operation. Heating of the control rod could be a consequence of fire of the aircraft’s electricity network, in immediate proximity from the control rod. This led to smoke in the cargo hold, unexpected triggering of alarm systems, aircraft equipment failures, and the auto-shutdown of two engines. Electrical bunch-conductors, distributors, blocks and aggregates of the aeronautical equipment, located in the 15-25 frames zone (ceiling of the cargo compartment) came under intense attack by fire, resulting in a collision collision with the ground, as a result of which it was impossible to accurately determine the primary origin and reason of the fire.