Last updated: 20 February 2017
Narrative:An Antonov 24RV passenger plane, registration RA-47302, crashed into the Ob River, Russia, killing seven passengers. The airplane took off from Tomsk (TOF) at 10:10 local time on domestic flight SP5007 to Surgut (SGC).
|Date:||Monday 11 July 2011|
|C/n / msn:|| 57310302|
|First flight:|| 1975|
|Total airframe hrs:||48489|
|Engines:|| 2 Ivchenko AI-24VT|
|Crew:||Fatalities: 0 / Occupants: 4|
|Passengers:||Fatalities: 7 / Occupants: 33|
|Total:||Fatalities: 7 / Occupants: 37 |
|Airplane damage:|| Damaged beyond repair|
|Location:||17 km (10.6 mls) SW of Strezhevoy ( Russia)
|Phase:|| En route (ENR)|
|Nature:||Domestic Scheduled Passenger|
|Departure airport:||Tomsk-Bogashevo Airport (TOF/UNTT), Russia|
|Destination airport:||Surgut Airport (SGC/USRR), Russia|
About 11:48 the pilot reported an engine fire, stating that he would perform an emergency landing. The airplane came down in the Ob River, close to Strezhevoy Airport.
Probable Cause:The aircraft accident involving An-24RV RA-47302 occurred during a ditching, which was performed because of a fire in the left AI-24-2 engine nacelle series number N49312005. Destruction of the aircraft with the loss of life was due to the collision of aircraft and underwater obstacles, which the crew could not anticipate and prevent.
The occurrence of the fire most likely was caused by depressurization system venting left engine failure due to the centrifugal breather CA-24 number G872VT9 with subsequent release air-oil emulsion in the engine compartment of the engine, as well as delayed engine shutdown when the crew received a warning of "shavings in the engine oil", pressure fluctuations of the left engine within ±5 kg/cm2, a burning smell and the oil pressure dropping below the limit.
Failure to inform the crew about the excessive vibration of the engine was due to the deterioration of the vibration measurement system, IV-41AM, most likely due to the changes (fluctuations) of the engine rotor speed in the process of the destruction of the bearing of the compressor rotor rear support and (or) misalignment of the IV-41AM-system which might have affected the decision of the crew to turn off the engine.
The cause of the destruction of the Rotary pointer LP-24 # G872VT9 was the destruction of the impeller due to prolonged exposure to air/oil emulsions with high compressor rotor temperature, due to the destruction of the ball bearing rear bearings.
Significant secondary damage to parts of the compressor rotor rear support site did not clearly establish the cause of the destruction of the bearing. Most likely, the destruction happened during its work with high misalignment of the rings.
Increased misalignment of the rings could be:
- as a result of adverse addition available to the mating parts back support assembly of the compressor rotor beats (within TU) with the beat bearing obtained because of his irregular installation at an average (according to technical condition) engine repairs in JSC "Aramilsky ARP";
- due to deviations from TU geometry of mating parts back support assembly of the compressor rotor.
Contributing factors of the accident, most likely, were:
- the psychological unpreparedness of the pilot in command to turn off the engine in flight due to lack of experience of actual flight with one engine inoperative;
- late detection of a fire by the crew and, as a consequence, failure to take timely measures to extinguish the fire. Due to lack of objective information to determine the cause of the late detection of a fire by the crew, a full assessment of the performance of all elements of the fire alarm system MTP-MTP-2A and 7, could not be made.
» Tomsk Airport
» RIA Novosti
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This map shows the airport of departure and the intended destination of the flight. The line between the airports does not
display the exact flight path.
Distance from Tomsk-Bogashevo Airport to Surgut Airport as the crow flies is 866 km (541 miles).