Aeroflot flight 11

Aeroflot flight 11
	A structurally identical Antonov An-2 from Aeroflot
Accident summary
Accident type	Loss of control through shifting the center of gravity
place	15 km southeast of Repinka , Kazakh SSR;
date	December 10, 1960
Fatalities	12
Survivors	0
Aircraft
Aircraft type	Antonov An-2T
operator	Aeroflot
Mark	CCCP-33181
Departure airport	Semipalatinsk Airport , Kazakh SSR;
Destination airport	Abai Airport , Kazakh SSR;
Passengers	10
crew	2
	Lists of aviation accidents

The Aeroflot Flight 11 (Flight number: SU11 ) was a regional line flight of Aeroflot from Semipalatinsk to Abai in the Kazakh Soviet Socialist Republic . On December 10, 1960, this flight was carried out with an Antonov An-2T , which got out of control in flight and crashed. All 12 people on board were killed in the accident.

machine

The affected machine was a Soviet -made Antonov An-2T that was less than three years old at the time of the accident. The machine had the factory number 114547317 and the model serial number 145-17 . The roll-out took place on September 14, 1960. On October 4, 1960, the aircraft was handed over to the Kazakh division of Aeroflot , where it received the aircraft registration number CCCP-33181 . The single-engine commuter aircraft with STOL properties was Neunzylinder- with a radial engine of the type Schwezow ASch-62IR equipped. By the time of the accident, the Antonov had completed 149 hours of operation.

Passengers, crew and luggage

Ten adult passengers took the flight from Semipalatinsk to Abai. There was a two-person crew on board the machine, consisting of a flight captain and a first officer. No flight attendants were provided on the regional flight. There were 106 kg of luggage on board, the take-off weight of 4,945 kg was within the normal range.

Weather as reported

According to an indicative (i.e. non-binding) weather report received before departure, there should be a cloud cover of stratus and cumulus clouds at a height of 600 to 1,000 meters, coupled with snowfall and a north-westerly wind with wind speeds of 35–45 km / h. Visibility should be four to six kilometers.

Course of the flight and course of the accident

At 8:10 a.m. local time, the captain of the machine and other pilots of the airline were informed about the meteorological conditions along the planned flight route. The validity of the weather report extended from 8:30 a.m. to 9:30 a.m. local time, whereby this weather forecast was given in the flight plan as "indicative". When the captain submitted the flight plan, the air traffic controller on duty refused permission to take off because the form was written under a different name and it did not correspond to the period of validity of the weather forecast required for the flight. The service manager was then called in. Although he recognized the note on the weather report, he did not take any action to request a valid weather report. Rather, he made the decision to allow the pilot to fly without a valid weather forecast in the flight plan form.

The single-engine machine took off from Semipalatinsk at 9:17 a.m. local time. The flight was conducted in difficult weather conditions, which worsened along the way. The captain had the machine rise to an altitude of 650 meters after take-off and was in constant communication with air traffic control. He reported that visibility was two to four kilometers. At a distance of 45 kilometers from Semipalatinsk Airport, he reported visibility of two kilometers. Air traffic control then asked the captain to return to the airport of departure after 15 minutes of flight time and thus two minutes after the expiry of the validity of the weather report, as a safe flight could not be accomplished under the prevailing meteorological conditions. At 9:36 a.m. local time, radio contact with the machine was broken.

Accident investigation

After radio contact with the machine was lost, the search for the wreck began. This was found at 13:03 local time at a distance of 45 kilometers on a course of 186 degrees from Semipalatinsk Airport, near the village of Repinka.

The immediate cause of the accident was found to be a sudden loss of speed and stall on the machine after a loss of vertical controllability. This event occurred after the aircraft's center of gravity was shifted back over 40-42% in flight. This incorrect weight distribution occurred after several passengers had gone to the rear of the machine, where the toilet was. Corresponding traces on the structural elements of the tail section and the tail unit support this knowledge. When the angle of attack of the aircraft began to increase, the rest of the passengers could have slipped into the rear of the cabin due to insufficiently reliable fixation of the seats and the lack of seat belts. In addition, the flight of the turnaround for the return to Semipalatinsk may have contributed to the stall. After the loss of speed at a relatively low altitude of around 500 meters, the crew could no longer intercept the stern-heavy machine from the stall. This was made more difficult by the restricted view and the not clearly recognizable horizon under whiteout conditions due to the weather .

The main cause of the accident was identified as the poor organization and handling of the flight at Semipalatinsk Airport, which enabled the aircraft to be cleared for take-off and take-off, even though there was no valid weather forecast for the route and destination airport. One of the contributing factors was the poor meteorological advice at Semipalatinsk Airport, as a weather report was published which forecast weather that was above the weather minimum, which did not correspond to the factual conditions along the flight route. The inadequate cooperation between the civil aviation weather service AMSG and air traffic control in Semipalatinsk was also criticized, as was the weak meteorological infrastructure for determining weather forecasts for the region around Semipalatinsk.

swell

Aircraft accident report An-2, CCCP-33181 on airdisaster.ru (Russian)
Crash of an Antonov AN-2 near Semipalatinsk: 12 killed , B3A - Bureau of Aircraft Accident Archives
Accident report An-2, CCCP-33181 in the Aviation Safety Network
Operational history and accident report An-2, CCCP-33181 , russianplanes.net (Russian)