Tupolev TU-154

It was determined that the crew selected the left main fuel tank to feed all three engines after takeoff from Yuzhno-Sakhalinsk. During 35 minutes of flight, the automatic pilot system was able to control and counteract the imbalance caused by the fuel consumption on one side only. Eventually, the aircraft started to bank right and the crew reaction to an unexpected situation was non compliant, causing the aircraft to enter an uncontrolled descent.

It was determined that the crew failed to prepare the flight according to published procedures. The mass and balance sheet was incorrect. At the time of the accident, the total weight of the aircraft was six tons above MTOW and the CofG as too far forward.

It was determined that the loss of control was the consequence of poor maintenance. The previous evening, the autopilot yaw-channel had been erroneously connected to the bank control and the bank-channel to the yaw control, after maintenance was completed at an unapproved facility.

The commission found that the air starter malfunction occurred when the engine was started due to a structural element of the air conditioning system, probably a fragment of the air-to-air radiator (VVR) splitter of engine n°2, hit under the constant pressure flap. This became possible due to the lack of protection against the ingress of foreign objects from the air lines and the low operational reliability of the VVR. A constant supply of air under pressure from the engines operating at a mode close to the nominal through an open damper led to the starter not switching off and the turbine rotor spinning up to off-design speed with the alarm "Dangerous starter speed" being triggered, which was detected by the flight engineer after starting all the engines. Pressing the starter shutdown button did not turn off the alarm. There were no other signs of failure other than the operation of the warning lamp. The crew, believing that the alarm was false, made the wrong decision to take off, which was a consequence of the unwillingness to act in such a situation due to shortcomings in the regulatory documentation, information support, as well as insufficient information content of the starter's technical condition monitoring system in the cockpit. Laying the mains of all three hydraulic systems through the fire-hazardous compartment of the engine n°2 is a constructive disadvantage of the Tu-154M aircraft.

Shot down by a surface-to-air missile fired by Abkhazi separatists.

It is believed that the collision was the consequence of a poor coordination between civil and military ATC.

The probable cause of accident has been attributed to :
- The failure of the Pilot-in-Command to divert to Ahmedabad when he was informed that the RVR on runway 28 was below the minima applicable to his flight.
- The switching on of landing lights, on the instruction of the second Captain, at a height of only about ten metres, resulting in the loss of all visual references due to the blinding effect of
light reflections from fog.
- The failure of captain to carry out a missed approach when visual reference to the runway was lost.

It was determined that the aircraft was not properly aligned with the runway centerline upon landing after the crew mistook the runway edge lights with the runway centerline lights.