Aeroflot Flight 31 (1955)

Aeroflot Flight 31 was a cargo flight from Moscow-Bykovo Airport to Koltsovo Airport with a stopover in Gorky Airport. On January 13, 1955, the Lisunov Li-2 operating the route crashed during takeoff after the right engine failed. The investigation assumed a sabotage to be the cause of the crash.

Aircraft
The accident aircraft was a Lisunov Li-2T (registration CCCP-Л5000, serial number 33444902). It first flew in 1953, and its airframe had logged 2,188 hours by the time of the accident.

The aeroplane was carrying 1,989 kg of cargo, which consisted of 1,828 kg of mail and newspaper, 92 kg of clothes, and 69 kg of aircraft parts to Sverdlovsk.

Accident
The pilot performed takeoff at 11:28. At 20–30 m, the right engine failed. Quickly, the aircraft lost height, colliding with multiple trees and hitting a house a kilometre away from the airport at 11:30, killing all five crew members on board. The wreckage then caught fire, destroying it and the house. There were no ground fatalities, as the owner had left just minutes before the crash.

Cause
The investigation determined the cause to be a sabotage, evidenced by a nut or an M4 female screw placed in the fuel system of the Li-2, causing the fuel pump to fail. Eight days before the crash, a similar case was reported.