Aeroflot Flight 2174
An investigation revealed the aircraft entered icing conditions leading to a loss of control.As ice accumulated the crew added power to counter the effects of the ice build up but control of the aircraft was lost and it crashed at a high rate of descent 13 kilometers northwest of the runway and 1,130 meters to the right of its centerline with the landing gear and flaps retracted.The construction of the airliner was completed on 4 April 1965 and it had sustained a total of 10,913 flight hours and 8,544 takeoff and landing cycles before the crash.[1][2][3] Investigators discovered that under the conditions the aircraft was operating prior to the crash approximately 15 millimeters of ice would have developed creating significant drag and undermining the wings ability to generate lift.Investigators examining the wreckage found the anti-icing system switches in the off position and confirmed that the anti-ice was not operating during the crash sequence.