Sequence of Events
On a flight from Ulan-Ude to Nizhneangarsk, while descending to an altitude of 3,050 meters approximately 30 km from the destination airport, the crew contacted air traffic control and reported the failure of the left engine. The approach was continued to runway 22. After touchdown, the crew initiated the braking procedure when the airplane deviated to the right and then veered off the runway. It rolled through a grassy area, went through the perimeter fence, and eventually impacted the building of a sewage treatment plant located 380 meters to the right of the runway centerline. The airplane was destroyed by a post-crash fire. The captain and the flight engineer were killed, while the copilot was seriously injured. Ten other occupants were injured.
Probable Cause
The official investigation determined that the accident occurred during landing with one engine inoperative as a result of a longitudinal-lateral rollout beyond the runway and subsequent collision with a building outside the aerodrome, resulting in damage to the aircraft structure and a fire. The landing was performed on a runway with an available landing distance of 1,503 meters, which was significantly less than the required distance of 2,160 meters for the actual conditions. The accident was most likely the result of the combination of the following factors:
- The decision by the pilot-in-command (pilot flying) to land without calculating the required landing distance.
- The incorrect choice by the pilot-in-command of the type and trajectory of the approach, which made it impossible to reduce the flight speed in time. Instead of performing a visual maneuvering ('circle-to-land') maneuver provided for in the approach pattern and agreed upon with the air traffic controller, the crew performed a visual approach.
- The absence in the airline's flight manual and the aircraft's flight manual of procedures for performing a visual approach maneuver ('circle-to-land' maneuver).
- Failure of the crew to take measures to go around for a second approach despite a significant discrepancy between the actual flight parameters and the criteria for a stabilized approach specified in the airline's flight procedures.
- Lack of crew coordination and cross-checking.
- Failure to follow a number of standard operating procedures in terms of informing the pilot-in-command by other crew members about significant deviations of actual flight parameters from the published values.
- Insufficient crew resource management.
- Landing at a significantly high speed of 275 km/h instead of the recommended 220 km/h, which led the aircraft to land 530 meters past the runway threshold.
- Incorrect use of the main landing gear wheel braking system by the crew, resulting in premature compression of the brake pedals (in the air), which, upon repeated contact, led to landing on the braked wheels of the right main landing gear with destruction of the tires and, subsequently, to the aircraft rolling sideways.
- Increased psychological and emotional stress on the part of the captain, compounded by his particular mental characteristics, contributed to the adoption of unreasonable decisions in the situation that had arisen.
The left engine failed in flight due to abnormal operation of the fuel control system, probably the ADT-24. Due to the high degree of destruction of the system by fire, it was not possible to definitively determine which unit failed and the cause of the failure. The abnormal adjustments of the left engine and deviations in the operation of its fuel control system manifested themselves long before the day of the accident and could have been detected by both flight and engineering personnel.