Investigation Summary
The investigation revealed that during taxiing, the flight mechanic observed the number 3 engine's turbine outlet temperature (MGT) exceeding 700 degrees Celsius, well above acceptable limits. Despite this indication of a malfunction, the crew proceeded with the takeoff. The number 3 propeller was never locked or feathered, and the engine remained in ground idle mode throughout the roll. As the other three engines provided forward thrust, the windmilling propeller on the number 3 engine created increasing drag (negative thrust). The crew did not increase power to the number 3 engine, likely fearing a further temperature excursion, but also failed to initiate a rejected takeoff. The aircraft reached a maximum speed of 220 km/h (140 mph) but could not rotate. It overran the 2,439-meter runway and a 90-meter concrete overrun area before impacting the terrain. The two survivors were technicians seated in the rear of the aircraft, away from the cockpit.
Final Conclusions
The Interstate Aviation Committee (MAK) released its final report in October 2022, concluding that the probable cause was the crew's decision to conduct a takeoff with an inoperative engine whose propeller was not feathered. The resulting negative thrust prevented the aircraft from reaching liftoff speed. The crew's failure to abort the takeoff once the performance deficiency became apparent led to the runway overrun and subsequent destruction of the aircraft.
Photographic Evidence (1)
Video Analysis
No video analysis linked for this case file yet.
Airframe & Maintenance
Crew Experience
Captain
Rashid Shaydanov, 66 years old. An Uzbekistan national.
First Officer
Altay Abdullayev, 35 years old. An Azerbaijani national.
Systems & Failure Modes
Ivchenko AI-20M-6 Engines
The aircraft is powered by four turboprop engines. Engine number 3 suffered a temperature excursion during taxi, leading to it being left in ground idle during takeoff.
Propeller Feathering System
A safety system designed to turn propeller blades parallel to the airflow to reduce drag in the event of an engine failure; in this accident, the system was not engaged for the failed engine.
Negative Thrust Warning
A cockpit alert that triggered during the takeoff roll, indicating that the number 3 propeller was creating drag rather than forward thrust.
Interesting Facts
- 01The aircraft was 53 years old at the time of the accident and was scheduled for retirement five months later.
- 02The crew consisted of one Uzbek, three Ukrainian, and five Azerbaijani nationals.
- 03The two survivors were Ukrainian technicians who were not in the cockpit during the crash.
- 04The number 3 engine propeller was neither feathered nor latched to the flight stop during the takeoff attempt.
- 05The takeoff was attempted in gusty wind conditions (14 knots gusting to 26 knots).
Safety Actions & Advisories
Crew Training and CRM Enhancement
The investigation emphasized the need for improved crew resource management (CRM) and adherence to standard operating procedures, specifically regarding the decision-making process for rejected takeoffs when engine parameters are abnormal.
Operational Oversight at Remote Airfields
Recommendations were made to ensure that ferry flights from remote locations without maintenance facilities do not bypass safety protocols, such as attempting takeoffs with known mechanical deficiencies to reach a maintenance base.
Location
ACCIDENT SITE · Coordinates taken from the wikidata coordinate.