63 fatalities

1973-05-11: Ilyushin II-18 (CCCP-75687) — Aeroflot - Russian International Airlines — Semipalatinsk, Kazakhstan

Semipalatinsk, KazakhstanFlight

On May 11, 1973, an Ilyushin II-18 (registration CCCP-75687) operated by Aeroflot - Russian International Airlines was involved in an aviation accident near Semipalatinsk, Kazakhstan in flight. 63 people were killed. Investigators recorded the probable cause as: The exact cause of the accident could not be determined. The assumption that the aircraft collided with an object was not ruled out. It is believed the crew may have started an emergency descent but the reason of this manoeuvre could not be established. This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 8 related events involving the same aircraft type or operator are linked below.

Sourcesthe Bureau of Aircraft Accidents Archives (B3A)Primary reportUpdated 1781232723Data APIEditorial standards

While cruising at 7,800 meters in good weather at night, the aircraft lost control during a left turn, entered a dive, and disintegrated at 5,000 meters. All 63 occupants were killed.

Incident Overview

While cruising at an altitude of 7,800 meters in good weather conditions at night, the pilot-in-command initiated a left turn. Control was lost shortly thereafter, and the aircraft entered a dive, spiraling toward the ground.

In-Flight Breakup

At an altitude of 5,000 meters, elements of the upper wing surface and the stabilizers detached. The aircraft disintegrated in the air before impacting a steppe approximately 84 kilometers south of Semipalatinsk.

Wreckage Distribution

Wings and stabilizer parts were found at a distance of about 3.5 kilometers from the main crash site, consistent with an in-flight breakup.

Occupants

The aircraft carried 63 occupants, all of whom were killed in the accident.

Investigation and Probable Cause

The official investigation determined that the exact cause of the accident could not be identified. The possibility of a collision with an object was not excluded. It was believed that the crew may have initiated an emergency descent, but the reason for this maneuver could not be established. The flight data recorder was seriously damaged in the crash and could not be read properly, limiting the analysis of the flight parameters.