1971 Surgut Aeroflot Antonov An-12 crash

The 1971 Surgut Aeroflot Antonov An-12 crash occurred on 22 January 1971, when an Aeroflot Antonov An-12B, registered CCCP-11000, flying from Tsentralny Airport, Omsk, in the Soviet Union's Russian Soviet Federated Socialist Republic (RSFSR), crashed 15km (9.3 mi) 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.

• http://en.wikipedia.org/wiki/1971 Surgut Aeroflot Antonov An-12 crash