An-24 crash in Tarko-Sale

The An-24 crash in Tarko-Sale was an aviation accident that occurred on the evening of Friday 9 December 1977 on the southern outskirts of Tarko-Sale. An An-24RV airliner of the Surgut Combined Aviation Detachment of Aeroflot began operating scheduled domestic flight SU-134 on the route Tarko-Sale — Surgut, but a minute after takeoff the airliner crashed into the ground (a swamp) and was completely destroyed. Of the 23 people on board — 18 passengers and 5 crew members — 17 were killed and 6 survived with injuries.

Timeline of events

Originally the aircraft was to take off on a magnetic heading of 20° and then turn onto the en-route heading of 190°. But since it was calm, the crew asked for permission to take off on a heading of 200°, so that after takeoff they would only have to turn 10° to the left, which could save time. The controller agreed to this proposal, and on 9 December 1977, in the evening at 19:25 local time (17:25 Moscow time), flight SU-134 departed from Tarko-Sale Airport 18 passengers and 5 crew members; the flight was operated by An-24RV tail number USSR-46795, flying from Tarko-Sale to Surgut. In total there were 23 people on board: 18 passengers and 5 crew members. At that time it was a moonless night, there were only scattered clouds in the sky, it was calm, the air temperature was −38 °C, and visibility was 5 kilometres.

Having climbed to a height of 120 metres at a speed of 295 km/h, the crew retracted the flaps. The retrimming of the aircraft with the elevator during this process was insufficient, so when the flaps were fully retracted the aircraft stopped climbing and began to descend. The crew then, by deflecting the ailerons by 6° and the rudder by 5°, quickly put the airliner into a right bank of 20° (1.5—2 times greater than in a standard manoeuvre), and the control column was briefly pushed "forward". Because of this the aircraft began to descend with a vertical speed of up to 9 m/s. The crew then returned the ailerons almost to neutral, but the rudder remained deflected to the right, so the right bank continued to increase and reached 30°. Then the elevator was returned to the position it had been in before the flaps were retracted, but because of the lack of retrimming of the aircraft the vertical speed reached 15 m/s and the indicated airspeed 425 km/h. 8—10 seconds after the aircraft was put into the right bank, the crew began to recover from this bank, for which they deflected the ailerons and the elevator, thereby reducing the bank and the vertical rate of descent. The crew did this at the rate of a standard manoeuvre, as if not suspecting that the ground was already dangerously close. The engines meanwhile continued to operate at takeoff power.

A second and a half later the An-24, flying on a heading of 200° with a right bank of 21°, at a true airspeed of 365 km/h (indicated — 425 km/h) and with a vertical speed of 8—10 m/s at a pitch angle of 4°, 2339 metres from the end of the runway, struck a frozen swamp covered with sparse woodland with its right wingtip. From the impact the airliner was completely destroyed and partially burned. The wreckage was scattered over an area 365—388 metres long and 50—60 metres wide. The rescue services that arrived found 9 survivors at the crash site: the navigator and 8 passengers. Later, however, 3 passengers died of their injuries in hospitals. In total 17 people were killed in the crash: 4 crew members and 13 passengers.