Investigation Summary
The investigation focused on the phenomenon of 'cold soaked' fuel causing ice formation even in the absence of active precipitation. The aircraft had arrived in Yerevan with fuel temperatures estimated at -21°C. Despite an ambient temperature of -3°C, the supercooled fuel in the wing tanks caused atmospheric moisture to freeze onto the wing surfaces, a process known as hoarfrost. The First Officer conducted a preflight walkaround and reported the wings were clean, but the investigation by the Interstate Aviation Committee (MAK) determined that visual and tactile inspections are often insufficient to detect the thin, clear layers of frost that can critically disrupt the airflow on CRJ-series wings, which lack leading-edge slats. Flight data showed the aircraft banked left almost immediately after liftoff at a height of approximately 5 meters. The crew attempted to counter the roll with right aileron, but the left wing remained stalled. The aircraft's sensitivity to wing contamination was a known factor; a similar accident had previously prompted a Transport Canada Airworthiness Directive regarding wing anti-ice usage. On Flight 1834, the crew activated engine anti-ice but did not activate the wing anti-ice systems, nor did they request deicing fluid application despite the freezing temperatures and high humidity.
Final Conclusions
The Interstate Aviation Committee (MAK) concluded that the probable cause was the asymmetric loss of wing aerodynamic properties due to frost contamination. Contributing factors included the crew's failure to activate wing anti-ice systems and the performance of a takeoff at speeds below those recommended for potentially contaminated wings. The report specifically highlighted that the situation was aggravated by the crew exceeding the recommended angular velocity (rotation rate) when lifting the nose wheel, which is difficult to monitor instrumentally and critical on the sensitive CRJ100 wing.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain
Viktor Shishlo, age 50
First Officer
Alexander Mukhin, age 44
Systems & Failure Modes
Wing Anti-Ice System
A system designed to prevent ice buildup on the leading edges; it was not activated by the crew during the takeoff sequence.
Leading Edge
The CRJ100 uses a 'hard' wing without slats, meaning any surface roughness from frost can cause a premature stall at normal takeoff angles of attack.
Interesting Facts
- 01All 21 people on board survived the crash, though seven passengers sustained serious injuries.
- 02The aircraft was destroyed, coming to rest inverted and split in two.
- 03The fuel in the tanks was significantly colder than the ambient air (-21°C vs -3°C), leading to frost formation (cold-soak).
- 04The CRJ100 wing design lacks leading-edge slats, making it highly sensitive to even minute amounts of ice contamination.
- 05The First Officer performed the preflight inspection instead of the Captain, contrary to procedures for icing conditions.
Safety Actions & Advisories
Enhanced Wing Inspection Procedures
The investigation emphasized that visual and tactile inspections are inadequate for detecting critical frost on CRJ wings, leading to stricter deicing requirements in cold-soak conditions.
Transport Canada Airworthiness Directive
Following the accident, Transport Canada issued an Airworthiness Directive requiring the use of wing anti-ice systems during the final stage of taxiing in specific weather conditions to prevent frost formation from cold-soaked fuel.