An-10 catastrophe near Syktyvkar

An-10A with tail number 11193 (factory - 0402104, serial - 21-04) was released by the Voronezh aircraft factory on June 30, 1960 and transferred to the General Directorate of the civil air fleet , which by July 7 sent its 75th air squadron of the Syktyvkar separate air group of the Civil Air Fleet . In total, at the time of the crash, the airliner had 2,156 flight hours (according to other data, 1,896 hours) and 1,158 landings ^{[1] [2]} .

The plane carried out a training flight, during which an inspection was conducted of the piloting technique at the flight crew of the Syktyvkar air unit. At 14:47, the An-10 took off at a magnetic rate of 187 °. The sky at that time was covered with continuous stratus clouds with a height of the lower edge of 200–300 meters, and the top - 1500–2000 meters, there was light snow, moderate south-westerly wind blew, the air temperature was about -4 ° C, and visibility was about 4— 6 kilometers. also, according to evidence from other aircraft, moderate icing was observed in the clouds. The crew of 9 people carried out flights in a circle using the OSP system and the SP-50 with the following alternation: two calls without landing and one with landing, that is, three calls on one person being checked. After completing 6 visits, two inspected persons who completed their program were landed ^[1] .

On board now were 7 people: FACS.F. Babikov and B.S. Nikolaev , Senior Pilot Instructor of the General Directorate of the Civil Air Fleet P.P. Solovyov , co-pilot I. K. Shugin , navigator Yu. I. Sadovsky , flight engineer I. S. Bordachev and the radio operator E.I. Sergeant . The 11th flight was carried out with a go-around , while the plane was piloted at that moment by Babikov sitting in the left-wing seat of the PIC, and Inspector Solovyov was sitting on the right-hand seat. When flying over the BPSS, the crew reported on a missed approach , to which the KDP dispatcher instructed them to make a right turn with a climb of 600 meters. The crew confirmed the occupation of a height of 600 meters and announced the start of the first turn, and after that - the start of the second turn. Then, unexpectedly at 17:37, they reported from the aircraft: “We are falling, falling, falling ... the engines failed” . After that, the connection stopped ^[1] .

An-10 finished the second turn, or just finished it when three engines failed: No. 1, 2 and 3. The crew increased the power of the remaining No. 4 engine, but the asymmetry of the thrust led to the introduction of the airliner into the left bank. Declining at the rate of 15–20 ° and along a trajectory with a slope of 45–50 °, the An-10 at an angle of 15–20 ° and with a left bank of 80–90 ° at a low speed hit a forest 10.2 kilometers from the KTA Syktyvkar airport along azimuth 113 ° (east) and east of the village of Upper Maksakovka , after which it was completely destroyed and set on fire. All 7 people on board were killed ^[1] .

As it was possible to find out the technical commission, at the time of the disaster only the fourth engine was working, which was in take-off mode, while the other three were in autorotation mode and were not working. It is most likely that the engines failed due to ice formed at the air intakes , which then came off and hit the engine compressors. The reason for the formation of ice could be the imperfection of the An-10 anti-icing system ^[1] .

The cause of the disaster is the failure of engines with the appearance of a significant negative thrust, which caused an emergency situation in difficult flight conditions in the clouds at night at an altitude of 600 meters.

Probable causes of engine failure:

1. Cutting the fuel with valves of hydraulic stop KTA-5F due to the increase in pressure in the discharge line from the block of valves EUG-93 as a result of blockage of the pipeline.
2. Ice entering the engine compressors due to:
   • Insufficient efficiency of air intake heating
   • Untimely activation of the icing alarm and activation of the air intakes by the crew. At the same time, according to the testimony of two pilots who left the board after the sixth flight, the heating of the air intakes was turned on during the entire flight and was not turned off.

Related causes:

1. The absence on the plane of unbeatable artificial horizon
2. The absence of KFL-37 type feathering buttons on the plane and the inconvenient arrangement of engine failure signaling lights
3. The lack of training for the flight crew in autorotation flights over the past two years due to the limitations of the autorotation time imposed by the OKB to 1 minute.

- ^[1]