Date & Time:
Jul 24, 1967 at 1532 LT
Type of aircraft:
Antonov AN-2
Operator:
Registration:
18253
Flight Phase:
Flight
Flight Type:
Government
Survivors:
No
Site:
Plain, Valley
Schedule:
Surgut - Tyumen
MSN:
1 168 473 08
YOM:
1961
Country:
Russia
Region:
Asia
Crew on board:
3
Crew fatalities:
3
Pax on board:
6
Pax fatalities:
6
Other fatalities:
0
Total fatalities:
9
Aircraft flight hours:
1182
Circumstances:
The airplane departed Surgut Airport at 1450LT on a flight to Tyumen, carrying six passengers and three crew members on behalf of the Soviet Ministry of Defense. After takeoff, the crew was cleared to proceed to the southwest at an altitude of 200 metres. Less than an hour into the flight, while cruising at an altitude of 150 metres in marginal weather conditions, the airplane collided with a Mil Mi-6 helicopter registered CCCP-11289 that was flying on the same route but on an opposite direction, flying from Tobolsk to Ust-Balyk. Following the collision, the airplane dove into the ground and crashed in a dense wooded area located 112 km southwest of Surgut. The crew of the helicopter was able to continue his flight and to land without further problem in Surgut. The Antonov was destroyed by impact forces and all nine occupants were killed.
Probable cause:
The accident was caused by the combination of the following factors:
- The air traffic controller in charge of the area authorized the crew of the helicopter to follow the same flight path as the airplane at the same altitude but in an opposite direction, and failed to each crew of the presence of a second airplane on the same route.
- Both crews neglected visual flight rules by continuing their flight in reduced visibility caused by low clouds and at an insufficient altitude.
The following contributing factors were identified:
- The Antonov crew deviated 12 km from the route originally specified in the flight plan and thus entered an area where flights were prohibited in that direction;
- The Antonov was flying at an insufficient altitude of 150 metres, even though it had been assigned an altitude of 200 metres;
- The Antonov crew was not maintaining radio communication with air traffic controllers and did not inform them of its position or the progress of its mission;
- The air traffic controller failed to inform both crews of the deteriorating weather conditions;
- The helicopter crew was not flying along the approved route, as they were following a direct path;
- The senior flight dispatcher on duty at Tobolsk Airport delegated oversight of the helicopter crew’s flight preparations to a trainee flight dispatcher who authorized the direct flight in violation of the approved route;
- The weather forecast for the first half of the Surgut - Tobolsk leg was incorrect.
- The air traffic controller in charge of the area authorized the crew of the helicopter to follow the same flight path as the airplane at the same altitude but in an opposite direction, and failed to each crew of the presence of a second airplane on the same route.
- Both crews neglected visual flight rules by continuing their flight in reduced visibility caused by low clouds and at an insufficient altitude.
The following contributing factors were identified:
- The Antonov crew deviated 12 km from the route originally specified in the flight plan and thus entered an area where flights were prohibited in that direction;
- The Antonov was flying at an insufficient altitude of 150 metres, even though it had been assigned an altitude of 200 metres;
- The Antonov crew was not maintaining radio communication with air traffic controllers and did not inform them of its position or the progress of its mission;
- The air traffic controller failed to inform both crews of the deteriorating weather conditions;
- The helicopter crew was not flying along the approved route, as they were following a direct path;
- The senior flight dispatcher on duty at Tobolsk Airport delegated oversight of the helicopter crew’s flight preparations to a trainee flight dispatcher who authorized the direct flight in violation of the approved route;
- The weather forecast for the first half of the Surgut - Tobolsk leg was incorrect.
