22 January 1971 Surgut Aeroflot Antonov An-12 crash

The 22 January 1971 Surgut Aeroflot Antonov An-12 crash occurred when an Aeroflot Antonov An-12B, registered CCCP-11000, flying from Omsk Tsentralny Airport, in the Soviet Union's (RSFSR) on 22 January 1971, crashed 15 km short of the runway on approach to Surgut International Airport, Surgut, RSFSR. An investigation found the aircraft's ice protection system was ineffective because the engine bleed air valves were closed during the flight; ice therefore built up on the aircraft causing it to go out of control.

Accident

In the first half of January 1971 CCCP-11000 was one of two Antonov AN-12s which, along with 3 crews from the 75th flying squadron were temporarily based at Omsk airport, these aircraft were used in transporting freight. On January 22 an order was received to fly CCCP-11000 to Syktyvkar, where routine maintenance work was to be carried out on the aircraft. It was decided to combine the flight with the delivery of 12 metric tons of freight to Surgut. The goods to be transported consisted mainly of rolls of netting, plastic floor tiles and other household goods, as well as a C-995 piledriver for use in construction. Aboard were two crews, the flight crew and a relief crew. The flight crew consisted of:

Captain - Sergei Alexeyavich Bakharev

Second officer - Anatoli Petrovich Dekhtarenko

Navigator - Valeriy Konstantinovich Bakhin

Flight mechanic-instructor - Mikhail Ivanovich Kazachkov

Radio operator - Anatoli Antonidovich Tichenko

Steward - Vladimir Mikhayilovich Malinin

The relief crew consisted of:

Captain - Leontiy Andreyevich Butov

Second officer - Anatoliy Mikhailovich Shama

Navigator - Pyotr Stepanovich Azarenkov

Flight mechanic - Anatoliy Mikhailovich Udayev

Radio operator - Nikolai Ivanovich Soklakov

Steward - Igor Ivanovich Pushnikov

Two others were also on board: an engineer from the 75th flying squadron; Nikolai Pavlovich Kayakan and loadmaster; Yevgeniya Rudolfovna Kramar.

At Surgut, according to the weather forecast provided to the crew, there were Stratocumulus clouds at a height of 500-700 m, visibility was 3-4 km, there was snow, with icing conditions in the clouds. After take-off at 18:09 Moscow time from Omsk airport the AN-12 climbed to a flight level of 6600 m.

At Surgut there was solid cloud at a height of 450 m, visibility was 5.5 km, a fresh breeze was blowing from the north and the air temperature was -9 C. At 19:20 the radar controller at Surgut gave permission for the crew of the An-12 to descend to a height of 4500 m, and then to a height of 1200 m. When the crew reported that they had reached a height of 1200 m, they were ordered to contact landing control. They approached the runway on a magnetic heading of 180° and the aircraft entered the second turn of its circuit whilst descending to a height of 400 m, the distance to the runway at this point was 11 km. At 19:34 Moscow time the crew reported that they were passing the outer marker beacon at a height of 400 m, which was acknowledged by the controller. At 19:36 Moscow time (21:36 local time), the aircraft was 11 km laterally and 16 km radially from the runway. The crew received the order to perform the third turn of their holding pattern, this instruction was acknowledged by the crew. This was the last communication that took place with the aircraft.

When the An-12 was at a distance of 18 kmto the North-East of Surgut airport at a speed of 330 km/h conducting a left turn, the aircraft experienced flow separation on the wing as a result of which it entered a progressive left turn and lost altitude. At this point, having deviated from its original course by 110°, and now on a bearing of 40° and with a left bank around 90° the aircraft crashed into the ground in the vicinity of the river Pochekuika and was completely destroyed with the wreckage catching fire.