What happened
On July 17, 2010, a flight plan was submitted for flight NI-9236, intended to operate from Keperveyem to Komsomolsk-on-Amur. The flight was originally scheduled for July 19, 2010, but was unable to proceed due to a takeoff prohibition. Consequently, the flight request was rescheduled for the following day, July 20, 2010.
Prior to the rescheduled departure, the aircraft, an Antonov An-12BK with registration RA-11376, underwent operational technical maintenance. This servicing was performed by the technical services of Vostok-Chukotka Airlines. During the ground maintenance phase, two specialists from the airline's technical department were present on board in the capacity of crew members as specified in the flight assignment.
The investigation
Records from the maintenance work order (No. 229) indicate that a pre-flight inspection was completed by the aircraft mechanic in accordance with the flight manual requirements. No discrepancies or defects were noted during the preparation of the aircraft for flight. The fuel load consisted of 13,500 kg of TS-1 fuel, treated with additive I-M, which was deemed sufficient for the route to Komsomolsk-on-Amur, including planned diversions to Khabarovsk and Yuzhno-Sakhalinsk.