Yak-40 crash near Dushanbe

The Yak-40 crash near Dushanbe was an aviation accident that occurred during the day on Thursday, 12 June 1980, in the vicinity of Dushanbe. A Yak-40 airliner of the Kurgan-Tyube Joint Air Detachment of Aeroflot was operating scheduled domestic flight Sh-88 on the route Leninabad — Dushanbe, but at Dushanbe Airport, on the airliner's path to landing at Dushanbe Airport, there were thunderstorm cells. The crew decided to fly around them, but while doing so the airliner deviated from its course and struck a mountain, being completely destroyed. All 29 people on board were killed — 25 passengers and 4 crew members.

Chronology of events

On 12 June 1980 at 13:04 local time (10:04 Moscow time) flight Sh-88 with 25 passengers and 4 crew members departed from Leninabad Airport; the flight was operated by Yak-40 registration CCCP-87689, flying from Leninabad via the Anzob Pass to Dushanbe, and after climbing the Yak-40 took up a flight level of 7200 metres. It was piloted by a crew whose commander (aircraft commander) was E. M. Lander. In total there were 29 people on board: 25 passengers (23 adults and 2 children) and 4 crew members.

On the section from the Anzob Pass to Dushanbe the sky was covered by scattered clouds with a base of 2500—2800 metres and tops of 6—7 kilometres; moderate turbulence was observed, a fresh westerly wind was blowing and there were thunderstorm cells. This was above the captain's meteorological minimum and did not prevent the flight and landing from being carried out. 73 kilometres remained to Dushanbe Airport when, at 13:32, the crew deviated 9 kilometres west of the airway centreline and began to fly around the thunderclouds. But the controller was informed of this only a minute later, when the deviation from the route had reached 10 kilometres. The controller permitted the crew to fly around the thunderstorms and also cleared them to descend to a height of 6000 metres at the Pugus NDB. At the same time, the area control centre controller did not monitor the airliner's flight and did not detect its lateral deviation until the moment when the Yak-40 had approached to within 67 kilometres of the airport. At 13:36 the crew reported passing the Pugus NDB at a height of 6000 metres. In reality they were still 37 kilometres from it; the error arose from a mistake in determining the wind speed, as well as from malfunctions of the radio compasses, which were caused by electrification of the aircraft while passing through dust haze, and also by the influence of thunderstorms located close to the flight path. Throughout all this the area control centre controller did not monitor the flight of flight Sh-88 and did not pass the crew information on their location. He merely passed the crew information about a bearing of 340° (relative to the aerodrome reference point), after which he instructed them to switch to the approach controller.

The Yak-40 was in fact 43 kilometres north-west of Pugus, but the approach controller did not determine its location when he cleared it to descend to a height of 4800 metres at the outer marker of Dushanbe Airport, and also indicated that the landing would be on a magnetic heading of 86°. Then, at 13:38, the aircraft turned onto a heading of 160° towards the outer marker and began to descend. During the descent the crew received from the approach controller a direct bearing of 330° and the instruction: "Expedite descent to 4800 metres". Since the aircraft was on a bearing of 330°, this meant that it had crossed the limiting bearing of 340° and deviated to the west, but this did not alert the controller, and he did not begin to monitor the flight more closely or to establish the actual location of the airliner. In turn, the crew, descending in cloud, could not correctly determine their location because of malfunctions of the radio compasses in conditions of severe turbulence and icing.

At 13:40 the pilots erroneously reported passing the outer marker at a height of 4800 metres, although it was still 43 kilometres away. But the approach controller, having the necessary radio equipment at his disposal, did not check whether the aircraft had actually passed the outer marker, and instead cleared it to descend to the circuit height — 3600 metres. Flying among mountains 4018 metres high, the crew began a descending right turn and took up a heading of 266° (reciprocal of the landing heading), after which it descended to the assigned height of 3600 metres. Without determining their location, the approach controller instructed them to switch to the circuit controller.

By that time the sky was already completely covered with clouds. When the crew contacted the circuit controller, he, like his colleagues, did not determine the aircraft's location and cleared it to descend to a height of 2100 metres towards the third turn on aerodrome pressure, attaching no importance to the fact that the airliner was outside the descent pattern and far to the right of the limiting bearing of 275°. Passing a height of 3000 metres, the crew reported that aerodrome pressure had been set on the altimeters — 694 mm Hg. The pilots also determined that they were far to the north of the approach pattern and levelled off at a height of 2840 metres, stopping the descent, after which they began to turn onto a heading of 180° …