Date & Time:
Dec 4, 1984 at 0813 LT
Type of aircraft:
Let L-410
Operator:
Registration:
CCCP-67225
Flight Phase:
Takeoff (climb)
Flight Type:
Scheduled Revenue Flight
Survivors:
No
Site:
Plain, Valley
Schedule:
Kostroma – Ivanovo – Ulyanovsk
MSN:
77 07 06
YOM:
1977
Flight number:
SU637F
Country:
Russia
Region:
Asia
Crew on board:
2
Crew fatalities:
2
Pax on board:
8
Pax fatalities:
8
Other fatalities:
0
Total fatalities:
10
Aircraft flight hours:
3534
Aircraft flight cycles:
3007
Circumstances:
The twin engine aircraft departed Kostroma Airport at 0809LT on a flight to Ivanovo, carrying eight passengers and two pilots. After takeoff, while climbing in marginal weather conditions, the crew was instructed to report once the altitude of 1,800 meters would be reached but the crew failed to respond. The aircraft entered an uncontrolled descent and crashed in a wooded area located 11 km north of the airport. The aircraft was destroyed and all 10 occupants were killed.
Probable cause:
The exact cause of the accident could not be determined with certainty as investigations were hampered because the aircraft was not equipped with CVR/FDR. Nevertheless, it is believed that the pilot-in-command lost control of the airplane after he suffered a spatial disorientation caused by the malfunction/dysfunction of the horizontal gyro.
