An-24 crash in Samarkand

The An-24 crash in Samarkand was an aviation accident that occurred on 19 December 1978 in Samarkand. An Aeroflot An-24B aircraft was performing a training flight Samarkand-Samarkand, but during the flight it lost control and crashed to the ground. All 5 crew members on board were killed.

Crash

The aircraft was performing a training flight, and it was piloted by a crew from the 163rd Flight Detachment, whose commander (aircraft commander) was instructor pilot A. F. Tsibizov. The crew also included two co-pilots, V. V. Abramov and V. G. Kazanov, who were to be retrained as captains, navigator L. M. Kramer and flight engineer V. M. Lyamtsev. At 06:15 (04:15 Moscow time) the An-24 departed from Samarkand Airport. Carrying out the flight programme, the crew completed eight landing approaches without deviations.

On the ninth approach, landing with one propeller inoperative was being practised. Cloud cover at that time was 5 oktas, a crosswind was blowing, and horizontal visibility was up to 40 km. While practising the landing on one engine, the crew feathered the right propeller. By the instructor's decision, unlike the first eight, the ninth approach was flown not on the normal glide path but under conditions in which a restriction of 25 m was imposed on the height of passing over the runway threshold, and the overshoot on landing was to be 400 m, of which the instructor warned the other crew members.

With the flaps extended to 15° and the landing gear down, the airliner passed the outer marker at a height of 260 m instead of the established 235 m. The descent was taking place at an increased vertical speed, and 400 m before the inner marker the aircraft was already 15 m below the glide path when, at a speed of 238 km/h, the power of the left engine was reduced from 22° to 18° on the UPRT. When 3 seconds remained before passing the inner marker, the flaps were further extended to the landing position of 38°, which at the same time led to an increase in aerodynamic drag, but the engine power was not increased, as a result of which the speed began to fall. The descending aircraft also began gradually to drift to the left of the runway centreline. Since the runway threshold was to be passed at a height of 25 m with touchdown 400 m beyond, and taking into account that the airliner was already 15 m below the calculated glide path (2°30’), the pilots tried to reduce the rate of descent, for which they pulled the control columns slightly "towards themselves", thereby increasing the deflection angle of the elevators. However, this action only increased drag and further reduced the flight speed, which had already fallen below that recommended by the flight manual.

The An-24 passed the inner marker at a speed of 228 km/h, 25 m to the left of and 10 m below the glide path, in practically level flight. At that moment the wind changed from a crosswind to a headwind (azimuth 100°, 4 m/s, gusts up to 7 m/s). Under such conditions, with only the left engine working, and even that at low power, the thrust was already insufficient and the aircraft began to descend faster than calculated. When 600 m remained to the runway threshold, the engines were briefly (for 10 seconds) set to takeoff power. But since only the left propeller was working, a yawing moment arose which began to swing the aircraft to the right, which the pilots tried to counter by deflecting the rudder fully to the left, and the resulting bank they countered by deflecting the ailerons. On a heading close to the landing heading, the An-24 began to climb and crossed the runway threshold at 25 m above the ground, while being 5—10 m to the right of the centreline. The speed fell to 190 km/h, as a result of which the rudder lost effectiveness and the aircraft began to turn to the right at an angular rate of 3°/sec.

Having decided to abandon the approach, the crew retracted the landing gear. Meanwhile the aircraft was deviating more and more to the right, while climbing slightly. The right bank began to grow rapidly, despite the maximum deflection of the control wheel to the left. After another 7 seconds the flaps were retracted, which brought the airliner to supercritical angles of attack and to the onset of a stall.

At 09:04 (07:04 Moscow time) the An-24, flying on a heading of 190° at low forward speed, at an angle of 10—15° and with a right bank of 80°, sideslipping onto the right wing, struck the ground 690 m from the runway centreline and 1120 m from its threshold, a few metres from the bank of an irrigation canal near the fence of a motor depot. On impact the aircraft was completely destroyed and partially burned, and all 5 people on board were killed.