Four-Engine Aircraft Crash Near Moscow-Sheremetyevo After False Engine Fire Alarms (CCCP-86513)

Incident Overview and Initial Climb Details A four-engine aircraft departed Moscow-Sheremetyevo Airport on a scheduled service to Freetown, with an intermediate stop in Dakar. After takeoff from runway 24R, the crew raised the landing gear during the initial climb. Eight seconds later, a fire alarm for engine number 1 sounded. The crew shut down the engine in accordance with the Flight Manual and used the three stages of fire suppression systems. Thirty seconds later, a fire alarm for engine number 2 also sounded. The same procedure was adopted for the second engine, and the crew declared an emergency. ## Loss of Control and Impact At a speed of 320 km/h and a height of 160 meters, with the undercarriage retracted and the flaps down at 30 degrees, the pilot-in-command initiated a right turn. The aircraft was unable to maintain a safe altitude and lost speed and height while in a high angle of attack. From a height of 75 meters, the aircraft stalled, banked left to 70 degrees, then nosed down 20 degrees and crashed in a wooded area located in Mendeleyevo, about 11.4 km northwest of the airport. The aircraft disintegrated on impact, and all 90 occupants were killed. ## Official Probable Cause The official investigation determined that both fire alarms on engines number 1 and 2 were false. Hot air from a ruptured pipe of the air conditioning system had blown on the temperature sensors.