Republic of Yakutia (Sakha)

Failure and fire on engine n°3 for unknown reasons.

It was determined that the crew disengaged and re-engaged several times the automatic pilot system for unknown reasons. This created tail and elevators' movements and the reaction of the crew was inappropriate. The aircraft suffered violent oscillations on both roll and pitch axis then entered an uncontrolled descent. The partial disintegration was the consequence of aerodynamic forces that exceeded the aircraft certification.

Wrong takeoff configuration on part of the crew who neglected several published procedures. The following contributing factors were reported:
- The total weight of the aircraft at the time of the accident was 7,5 tons above MTOW,
- Lack of crew training,
- Premature retraction of flaps during initial climb,
- Insufficient rate of climb/climbing speed.

The accident was the consequence of a poor planned approach and a wrong approach configuration. The following contributing factors were reported:
- Lack of crew training,
- It was the first time (except for one crew member) that the crew was landing at Yakutsk-Magan Airport,
- Marginal weather conditions (visibility below minimums at the initial destination airport),
- Failure to comply with flight crew recommandations,
- Poor crew instructions and interaction,
- The crew failed to follow the published procedures for a standard approach and landing,
- Deviations in aircraft piloting during approach and landing, causing the aircraft to land too far down the runway,
- The pilot-in-command maintained the aircraft in a nose-up attitude for a period of 9 seconds between the main gear touchdown and the nose gear landing,
- The reverse thrust systems were not activated,
- The spoilers were deployed too late,
- Lack of leadership on part of the captain during the approach and landing,
- The crew did not make the decision to initiate a go-around procedure when the landing maneuver was obviously missed.

The accident was the consequence of an error on part of the flight engineer who mistakenly selected reverse thrust on engine n°2 and 3 only, letting both engines n°1 and 4 running at takeoff power.
The following contributing factors were reported:
- The spoilers could not deploy because reverse thrust was not activated on all four engines,
- The crew was disorganized during the landing phase,
- Poor crew coordination,
- The mistake committed by the flight engineer was identified too late by the rest of the flying crew, ¨
- Heavy verbal charge during the landing phase,
- Insufficient professional skills of the flight engineer.

It was determined that the crew failed to prepare the flight according to published procedures and failed to follow the pre-takeoff checklist. Investigations reported that the flaps were deployed at an inappropriate angle of 8° instead of the prescribed 30°. At liftoff, the copilot realized the mistake and reduced the engine power to abandon the takeoff procedure but the captain took over controls and decided to continue the takeoff. Thus, the poor crew coordination was considered as a contributing factor.

It was determined that the engine failed due to fuel exhaustion. The crew failed to return to the departure airport when weather conditions worsened with a visibility below minimums and the fuel quantity was insufficient for all flight.