Investigation Summary
The investigation into Flight 2415 focused on the failure of the PP-1PM artificial horizons, which likely occurred due to a malfunction in the 36V electrical system. Because the accident happened at night in poor weather (visibility approximately 1,500 meters), the crew had no external visual references to verify their attitude. As they initiated a turn to a heading of 265 degrees, the failed instruments provided incorrect bank information. The crew continued to apply right aileron, believing they were not yet at the desired bank angle, when in reality the aircraft had exceeded 60 to 70 degrees of bank. By the time the crew realized the instruments had failed and attempted to recover, the aircraft had reached a bank angle of 90 degrees and a speed of 580 km/h. The aircraft struck the ground at approximately 620 km/h just three minutes after departure.
Final Conclusions
The State Supervisory Commission for Flight Safety concluded the primary cause was crew disorientation resulting from the failure of the artificial horizons and the lack of a warning system to alert the pilots of such a failure. The failure was attributed to a likely malfunction in the 36V electrical supply. While one board member, Markov, argued for pilot error, he was overruled by the majority who cited the extreme difficulty of maintaining control without reliable attitude data in IMC. The investigation was hampered by the loss of the final six seconds of flight data and cockpit radio recordings, which were destroyed in the post-impact fire.
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Systems & Failure Modes
PP-1PM Artificial Horizon
The primary attitude indicator which failed, leading to the crew's loss of spatial orientation.
36V Electrical System
The power source for the flight instruments; its failure is the suspected cause of the horizon malfunction.
Interesting Facts
- 01Visibility at the time of the accident was approximately 1,500 meters with low cloud cover.
- 02The flight data and cockpit voice recorders were missing the final six seconds of data due to fire damage.
- 03The crash site was located approximately 9.5 to 10 kilometers from Sheremetyevo Airport.
- 04The aircraft involved was a Tupolev Tu-104B, a variant of the first Soviet jetliner.
Safety Actions & Advisories
Instrument Failure Warning
The investigation highlighted the lack of an adequate warning system to alert the crew when the artificial horizons were receiving insufficient power or providing erroneous data.
Known Controversies & Unanswered Questions
Dispute over Pilot Error
Reference ↗One member of the investigative board, Markov, formally disagreed with the final report, attributing the accident to pilot error rather than mechanical failure. He was overruled by the Gosavianadzor board.