Aeroflot Flight 1661

Aeroflot

Industry	Airline
Founded	1923
Headquarters	Moscow , Soviet Union

Template:Infobox aircraft occurrence Aeroflot Flight 1661 was a passenger service operated by an Antonov An-24 that crashed during its initial climb phase, approximately 25 minutes after departing from Tolmachevo Airport on April 1, 1970. All 45 individuals aboard lost their lives. Subsequent investigation determined that the aircraft collided with a radiosonde, resulting in loss of control.

Accident

Flight 1661 was a routine domestic route connecting Novosibirsk and Bratsk, Russia, with a scheduled stopover in Krasnoyarsk. The An-24 took off from Tolmachevo Airport’s runway 25 at 03:42 local time, proceeding on a heading of 251°. Shortly after liftoff, the plane executed a left turn and by 03:53 had reported an altitude of 4,200 meters to air traffic control (ATC), receiving clearance to ascend to 6,000 meters. At 04:10, ATC attempted to reestablish contact with Flight 1661 but received no response. The wreckage was located roughly 142 km from Tolmachevo Airport in a field; there were no survivors. Among those killed were members of a youth ice hockey team en route to a match.

Aircraft

The aircraft involved was an Antonov An-24B bearing serial number 79901204 and registered as CCCP-47751 under Aeroflot. Manufactured in 1967, it had accumulated a total of 3,975 flight hours and completed 3,832 takeoff and landing cycles prior to the accident.

Investigation

Examination of the crash site revealed distinctive damage to the plane’s nose section and radome, including the absence of a significant portion of the windshield. Components recovered from the debris included fragments of two radiosondes used at the time by the Federal Service for Hydrometeorology and Environmental Monitoring to gather meteorological data. Additionally, parts of the nose cone were found six kilometers away from the main wreckage area, showing signs of impact with a solid object. Investigators determined that the cause was an inflight collision with an external object—the radiosonde balloon assembly.

The official inquiry concluded that while climbing through approximately 5,400 meters altitude at a distance of 131 km from Tolmachevo, the aircraft’s nose cone struck a radiosonde. This collision destroyed the onboard weather radar and inflicted damage upon the cockpit area. Losing control, the Antonov entered a steep nose-down descent. At about 2,000 meters altitude and traveling at nearly 700 km/h, aerodynamic stresses caused the wings and horizontal stabilizer to detach due to forces exceeding structural limits. The fuselage continued for another 2.5 km before impacting terrain at roughly 300 km/h with a vertical velocity near 60 m/s. The flight duration totaled twenty-five minutes and twenty-five seconds.

See also

• Aeroflot accidents and incidents
• Aeroflot accidents and incidents during the 1970s
• Compilation of accidents involving sports teams