Investigation Summary
Flight 964 was a scheduled service from Kutaisi to Moscow. During the approach to Domodedovo at an altitude of 900 meters, the crew reported issues with their compass. An electrical failure had rendered the primary navigation instruments, including the artificial horizons, inoperative. In the darkness and snowfall, the pilots were unable to maintain a stable heading or attitude. While performing a turn to align with the runway, the crew overcorrected a slight right bank, leading the aircraft into a terminal left-hand spiral. The Tu-104 struck power lines and crashed into a field 16 km from the airport at a high bank angle. The investigation highlighted that the failure of the 36V DC power supply led to the loss of the navigation systems, which, combined with the lack of visual references, made the crash inevitable once spatial disorientation set in.
Final Conclusions
The investigation concluded that the primary cause of the accident was a failure of the 36V DC power supply, which led to the total loss of the aircraft's compass system and main artificial horizons. In conditions of night and poor visibility (IMC), the crew suffered spatial disorientation. While attempting to navigate the approach with failed instruments, the pilots inadvertently entered a steep left bank of approximately 70 to 75 degrees, resulting in a terminal spiral dive into the ground.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Systems & Failure Modes
Artificial Horizon
The primary gyroscopic instrument used to show the aircraft's orientation relative to the horizon; its failure led to spatial disorientation.
Compass System
The directional navigation system which failed due to electrical issues, leaving the crew unable to determine their heading.
Electrical Power Supply
The failure of this system disabled the critical flight instruments required for flight in low visibility.
Interesting Facts
- 01All 122 occupants, including 8 crew members, were killed.
- 02An electrical failure disabled the main gyros and compass system during the approach.
- 03The 122 souls on board consisted of 114 passengers and 8 crew members.
- 04The accident is the deadliest involving the Tupolev Tu-104 aircraft type.
- 05The aircraft entered a steep left bank of 75 degrees before impact.
- 06The aircraft hit the ground in a steep left bank of approximately 75 degrees.
- 07The aircraft was a Tupolev Tu-104B manufactured in 1960.
- 08The aircraft was reconfigured from its original 100-seat layout to 115 seats.
- 09The crash site was located 16 km northwest of Domodedovo Airport.
- 10The debris field measured approximately 248 by 180 metres.
- 11Visibility at the time of the approach was approximately 2,400 metres.
Safety Actions & Advisories
Instrument Reliability Review
The accident highlighted recurring issues with the Tu-104's artificial horizon and electrical systems, which had contributed to several other Aeroflot crashes (Flights 1912, 2415, and 3932).
Location
ACCIDENT SITE · Coordinates taken from the wikidata coordinate.