Aeroflot Flight E-35D

Aeroflot

Company type	State-owned enterprise
Industry	Aviation
Founded	March 17, 1923 (1923-03-17)
Headquarters	Moscow , Soviet Union (now Russia)
Products	Air transport services

Aeroflot Flight E-35D ended in tragedy on 1 August 1990 near Stepanakert when a Yakovlev Yak-40 aircraft, operated by Aeroflot, crashed, resulting in the loss of all 46 individuals aboard.

Aircraft

The Yak-40 bearing registration CCCP-87453 (manufacturer’s serial number 9431036, production number 36-10) was produced by the Saratov Aviation Plant on 9 September 1974. Shortly thereafter, it was delivered to the Ministry of Civil Aviation of the USSR and assigned by 7 October to the Armenian Civil Aviation Directorate’s 2nd Yerevan Aviation Detachment.

Accident

Flight E-35D was scheduled from Yerevan to Stepanakert and was commanded by Captain Ararat L. Dallakyan, with co-pilot Alexander Ovanisyan and flight engineer Zhora Davtyan. Initially carrying 30 ticketed passengers, the captain unlawfully allowed an additional 13 passengers without tickets to board. The aircraft departed Erebuni Airport at 09:41. Although the standard cruising altitudes for this route ranged between 5100 and 6600 meters, the crew received permission to fly at 4500 meters after passing the OPRS Andranik waypoint; however, this altitude was below the minimum safe altitude of 4516 meters.

At 09:47, Erebuni’s dispatcher instructed the crew to switch communications to the approach controller but incorrectly stated that the aircraft was 20 kilometers from departure airport instead of the actual distance of 35 kilometers. Upon contacting approach control, the crew was informed of the correct distance but continued using the erroneous figure for their navigation calculations, leading to inaccurate speed and position assessments that were further worsened by tailwind conditions. At 09:50, the crew reported crossing Andranik while actually being 17 kilometers beyond it; similarly, at 09:57, they claimed passing Azizbekov when they were already 21 kilometers past that point. The crew failed to conduct proper navigation checks during flight. Their ADF-9 radio compass had been tuned to Stepanakert airport’s beacon since departure, relying on passive navigation throughout. During the flight, they executed four left turns: at 09:50:10 to a heading of 110°, at 09:53:10 to 90°, then subsequently to headings of 81° and finally 75°. Due to their incorrect distance estimations, these maneuvers caused them to pass Andranik two kilometers left of course at 09:49 and Azizbekov four kilometers left at 09:55.

Notably, the flight path deviated from its prescribed route by being straightened. This adjustment stemmed from escalating hostilities in the Nagorno-Karabakh conflict during that period, which led Armenian crews to avoid Azerbaijani airspace out of safety concerns. The original approach procedure for Stepanakert involved a turn near OPRS Aghdam located within Azerbaijani territory; by straightening their trajectory, the captain intended to reach a transition altitude of 2400 meters on final approach and then proceed directly toward Stepanakert OPRS on a course of approximately 75°, facilitating a quicker approach.

At 09:59, although the crew reported passing OPRS Azizbekov, they were actually located about 21 kilometers beyond it and were instructed to switch communication to Kafan airport’s dispatcher. Upon contact, they were told to maintain an altitude of 4500 meters until reaching the Lachin traverse—the designated descent boundary—though this boundary was unofficial as it lacked marking or inclusion in Kafan or Stepanakert aerodrome flight manuals. The dispatcher did not track or inform the crew about their precise distance or bearing relative to Stepanakert airport. Likewise, the crew failed to report estimated times for passing Lachin or clarify their exact position.

By this time, Captain Dallakyan had begun questioning their positional calculations; however, poor weather conditions with a continuous cloud cover between approximately 3000 and 3300 meters obscured ground visibility. Spotting what he believed was a mountain peak at an elevation of around 2823 meters on their left side near Lachin traverse, he communicated an estimated descent time at exactly 10:03:00. The dispatcher granted permission for descent from safe altitude down to 3900 meters at Lachin traverse based on radar checks; however, the actual mountain height was significantly higher at approximately 3616 meters. Consequently, due to mislocation, descent began prematurely before reaching the designated traverse point. Since Kafan dispatch did not monitor the flight closely nor receive position reports from the crew upon reaching level flight at 3900 meters around 10:07, no corrective actions were taken. At about 10:08, while still descending without interruption and falsely reporting an altitude of 3900 meters to Kafan dispatch, they requested clearance to communicate with Stepanakert airport’s control center. Unaware of their true altitude or location—and lacking direct communication with Stepanakert controllers—the Kafan dispatcher authorized this handoff.

When contact was established with Stepanakert at approximately 10:08, positional error had expanded to roughly 24 kilometers. The crew planned a minimal maneuver landing and descended along a heading of about 75°, believing they were approaching the outer marker zone correctly. The captain informed Stepanakert controllers that they were entering controlled airspace at an altitude of around 3900 meters passing Lysogorsky pass and requested permission for descent down to transition altitude of roughly 2400 meters upon reaching the outer marker. Although Stepanakert airport lacked radar capabilities and thus situational awareness regarding actual aircraft location was limited, controllers cleared descent down to an altitude of about 3000 meters at the inner marker.

At precisely 10:09:57 while descending through cloud cover on course towards Stepanakert airport’s vicinity, the Yak-40 collided with terrain on Karabakh Ridge at an elevation near 2520 meters—approximately twenty-two kilometers west of Stepanakert airport—resulting in complete destruction of the aircraft and total fatality among all occupants. This accident represented the deadliest Yak-40 crash up until that time and remains among the most severe incidents involving this type as of recent records.

Causes

Summary: The catastrophe resulted from a combination of multiple factors:

1. The Captain breached established flight protocols by improperly navigating, altering the route unnecessarily, and initiating an unauthorized descent to a dangerously low altitude, which ultimately caused the aircraft to collide with mountainous terrain.
2. Air traffic controllers at Erebuni, Kafan, and Stepanakert airports failed to comply with air traffic control regulations within their designated zones. This was evident in their neglect of flight monitoring procedures and their failure to intervene when the crew deviated from navigation rules and flight operations, thereby missing the opportunity to prevent the aircraft from striking an obstacle. These lapses were influenced by deficiencies in the coordination of flight operations and air traffic management along the Yerevan–Stepanakert corridor by both Armenian and Azerbaijani UGA.