An-24 crash in Alma-Ata

The An-24 crash in Krasnoye Pole was an aviation accident that occurred on the morning of Tuesday, 24 March 1969 in the settlement of Krasnoye Pole. An An-24 airliner of the Alma-Ata Joint Aviation Squadron of the airline Aeroflot began operating scheduled passenger flight SU-2305 on the Alma-Ata — Karaganda — Sverdlovsk route, but immediately after takeoff both of the airliner's engines failed. Because of the engine failure the airliner began rapidly losing speed and pitching its nose up, after which it entered a stall and fell onto houses in the settlement of Krasnoye Pole, demolishing houses and being completely destroyed. Of the 31 people on board — 26 passengers and 5 crew members — 4 were killed and 27 survived.

Crash

On 24 March 1969 at 06:37 local time, flight 2305 departed from Alma-Ata Airport; the flight was operated by An-24 registration USSR-46751, which was preparing to fly from Alma-Ata to Sverdlovsk with an intermediate stop in Karaganda. There were 31 people on board: 26 passengers and 5 crew members. During takeoff the sky over the airport was overcast with nimbostratus clouds with a base of 150 metres, light snow and rain were falling with a northerly (azimuth 340°) wind, visibility was 4 kilometres.

At 06:37 the crew took off on a magnetic heading of 50°. Lift-off from the runway occurred at a speed of 180—200 km/h, and at a height of 5—7 metres at a speed of 200 km/h the landing gear was retracted, after which the An-24 began to climb with a vertical speed of 3—4 m/s. At a height of about 30—50 metres the captain noticed that the indicated airspeed had stopped increasing, so he reduced the vertical speed to 1—2 m/s, which increased the indicated airspeed to 210—220 km/h. At a height of 70—80 metres the captain gave the order to retract the flaps from the takeoff position (15°). But when the flaps had been retracted, two to three seconds later the aircraft began to shake and started turning sharply with a bank to the right and losing height, despite significant deflection of the controls to recover from this attitude.

The An-24 turned right by 40—45° and continued flying straight without bank, losing height and forward speed (down to 170 km/h), while also pitching its nose up more and more. 750 metres to the right of the runway, after clipping trees, the aircraft struck the ground with its tail section within the settlement of Krasnoye Pole. The impact split the fuselage into two parts, and the tail section separated. The aircraft burned out completely, and many residential and non-residential buildings in the settlement were damaged. A stewardess and three passengers were killed in the crash. There were no fatalities among the residents of the settlement.

Causes of the crash

The most probable cause is a loss of power of one or both power plants from the moment the landing gear was retracted, followed by a reduction in thrust of the right engine at a height of 70—80 metres, which caused the shaking and turning of the aircraft with a loss of forward speed and descent.

Dissenting opinion of the representatives of the Ministry of Aviation Industry (MAP): Violation of the Flight Operations Manual — performing the takeoff with flaps retracted, lift-off at a speed of 180—190 km/h with an angle of attack of 13° with possible icing — the aircraft had been treated with hot water, but "Arktika" fluid was not used.