Yak-40 crash in Zeya

The Yak-40 crash in Zeya was an aviation accident that occurred on Saturday evening, 29 August 1981, at Zeya Airport. A Yak-40 airliner of the Blagoveshchensk Joint Air Detachment of the enterprise Aeroflot was operating scheduled domestic flight SU-674 on the route Irkutsk — Chita — Zeya — Blagoveshchensk, but during the landing approach at Zeya Airport in difficult weather conditions it collided with trees, after which it crashed to the ground near the runway of Zeya Airport and was destroyed. Of the 34 people on board — 29 passengers and 5 crew members, three were killed and 31 survived.

According to the results of the investigation, the causes of the crash were the crew's violation of the weather minimum and a premature descent with the aim of establishing visual contact with ground references during the landing approach, with unsatisfactory air traffic control and meteorological support of the flight at Zeya Airport. The commission also noted that meteorological observations at the inner marker for the landing magnetic heading of 25° had not been organised. They were conducted from a site located near the control tower (1200 metres from the runway threshold), from where the inner marker area could not be seen visually, and the formation of fog in this area, with its rather complex geographical conditions, could not be detected by the weather observer.

Crash

On 29 August 1981, in the evening at 18:20 local time (12:20 Moscow time), flight 674 with 29 passengers and 5 crew members took off from the runway of Chita's Kadala Airport; the flight was operated by Yak-40 registration CCCP-87346, flying from Irkutsk to Blagoveshchensk with intermediate stops in Chita and Zeya. Having climbed, the airliner took up a flight level of 7800 metres. It was piloted by a crew whose commander (aircraft commander) was V. S. Tyulenev. The crew also included a checking pilot-inspector of the Blagoveshchensk air detachment, who was conducting a check flight under scheduled-service conditions in order to clear the trainee aircraft commander to perform independent flights on this. In total there were 34 people on board: 29 passengers and 5 crew members.

At 19:42 the crew was in the zone of the Magdagachi area control centre when it contacted the local air routes controller of Zeya Airport and asked about the weather at the alternate aerodrome of Zavitaya, to which the controller replied: "Zavitaya is technically serviceable, the weather is good, here we now have [visibility] two [kilometres] and it may be less, something-something is drawing an odd fog off the river". In reply the pilot-inspector told him: "It shouldn't be less than two hundred by two thousand" (vertical visibility — 200 metres, horizontal — 2000 metres; the meteorological minimum for the airport), which somewhat confused the controller. At 20:05, in the course of preparing to begin the descent, the crew again contacted the airport controller and requested the weather. In reply the controller passed on the information that the weather forecaster-observer had been about to pass on: "cloud 120 m, visibility less than 2 kilometres", after which he advised them to call again in five minutes. These weather conditions were below the meteorological minimum; however, at this point the crew showed overconfidence and, instead of seriously assessing the weather conditions at Zeya aerodrome, began to convince the controller that after descending to the decision height (DH), should it be necessary to divert to the alternate aerodrome, the available fuel reserve would fully allow this. Then the crew of flight 674, in violation of the instructions, told the controller that they intended to descend to the DH, to which the controller said that visibility at the airport was less than 2000 metres, as the visibility marker located 2 kilometres from the control room could not be seen, and therefore he advised them not to descend.

Since the controller had no information on the official weather for 20:05, because the observer of this airport's aviation meteorological station (AMSG) had not made the observation, but at the same time he could see that visibility was falling below the minimum, he demanded that the observer carry out an unscheduled observation of the visibility and cloud height. The controller also did not demand that the crew of flight 674 stop the descent and divert to the alternate aerodrome.

At 20:08 the observer telephoned the controller and reported: "cloud [height] 260 metres, visibility 2 kilometres". Without requiring these weather data to be documented on the appropriate form, the controller passed them to flight 674. These weather conditions corresponded to the meteorological minimum, which, according to them, allowed a landing at Zeya, so the crew, still in the zone of the Magdagachi area control centre, began to descend from flight level 7800 metres to 3000 metres, after which at 20:18 it entered the zone of Zeya Airport. The airport controller cleared the crew of aircraft 87346 to descend to the transition level (1800 metres), gave the aerodrome pressure (720 mm Hg) and cleared them to join the approach pattern at a height of 1200 metres on a magnetic heading of 25° (from the south). At 20:23 flight 674 reported passing the outer marker at a height of 1200 metres relative to the aerodrome level, in response to which the controller cleared them to continue flying the pattern.

At the same time the crew of flight 675, which was being operated …