An-24 crash in Sovetsky

The An-24 crash in Sovetsky was an aviation accident that occurred on the evening of Tuesday, 21 November 1989, in Sovetsky. An An-24B airliner of the Perm Joint Air Detachment of the enterprise Aeroflot was completing charter flight SU-37577 on the route Perm — Sovetsky, but during the landing approach at Sovetsky Airport the airliner clipped trees, after which it struck a road embankment and crashed into the ground, being completely destroyed. 32 people on board out of 40 — 35 passengers and 5 crew members — were killed; 8 survived, having suffered serious injuries.

Crash

However, when 6 kilometres remained to the runway and the height was 250 m, the vertical rate of descent increased to 5 m/s, but the crew did not notice this, as they were trying to correct a lateral deviation. As a result the airliner descended below the glide path and passed the outer marker 60—90 metres lower than required (120—150 metres versus 210). Noticing this, the pilots gradually reduced the vertical speed to zero and maintained level flight for a kilometre until they returned to the glide path, after which they continued the descent. At a height of 130 metres the flight engineer was supposed to give the call "Assess", but he did not do so, nor did he give the call "Decision height" at the corresponding height (100 metres). The captain himself did not inform the crew of his opinion at the decision height. The instructor flight engineer sitting in the cockpit did nothing to correct the errors made by the person he was checking.

When 300 metres remained to the runway threshold, the controller transmitted updated meteorological data which were below the minimum for the An-24, requiring a go-around. However, the crew did not do this; moreover, at a height of 75 metres the vertical speed increased to 6 m/s, thereby creating an emergency situation. After passing a height of 62 metres the altimeter setting alarm was triggered, but the descent did not stop. Only at a height of 35 metres did the pilots see that the airliner was heading into a forest, so they sharply pulled the control columns towards themselves, thereby raising the aircraft's nose and making it begin to transition into a climb, which led to a load factor of almost one and a half g. Also, someone moved the engines to takeoff power without a command. However, the crew did not manage to stop the descent completely.

180 metres before the inner marker, the An-24 struck trees with its right wing. From the impact the wing was destroyed, and the right engine shut down, with the right propeller automatically feathering. However, the left engine at that moment had already begun to spool up to takeoff power (the collision occurred a couple of seconds after the engine power was increased), which caused asymmetric thrust, which in combination with asymmetric lift (due to the destruction of the right wing) led to a right bank, which quickly reached 27°. The crew tried to counter it with maximum deflection of the rudder and ailerons, which initially reduced the bank to 12°. However, a couple of seconds later, due to flow separation on the stump of the right wing, the right bank began again to grow rapidly (16° per second). At 17:28:47 the An-24, having flown about 500 metres with a bank of almost 90°, 700 metres from the runway struck a road embankment with its right wing, flew over it and crashed into an earth bank, after which it was completely destroyed and burned. The rescue services that arrived found 8 seriously injured passengers at the crash site. The remaining 27 passengers and all 5 crew members were killed.