What happened
During the departure sequence, the Tupolev Tu-154 began its takeoff roll with the flaps in the retracted position. Flight data indicates the aircraft rotated at 280 kph and became airborne at 288 kph. Evidence from the runway, including tire marks, demonstrated that the aircraft overran the paved surface and impacted runway end lights before exiting the stopway.
As the aircraft climbed through approximately 15 feet, the pilot commanded the landing gear to be retracted and increased the pitch. During the gear retraction process, the opening of the gear doors increased aerodynamic drag. This caused the airspeed to drop to 305 kph, which matched the stall speed for the aircraft's takeoff weight. Consequently, the angle of attack rose to 17 degrees, leading to a stall of the left wing at an altitude of roughly 5 to 7 meters.
In an attempt to correct the leftward roll, the pilot applied full left aileron, which also deployed the right wing spoilers, and applied right rudder. During this period, the pilot instructed the flight engineer not to retract the flaps, suggesting the crew was unaware the flaps were already up. The flight engineer subsequently selected the flaps to the down position. The aircraft entered an unrecoverable stall at a speed of 300 kph.
Following the stall, the aircraft struck a high-voltage mast approximately 1200 meters beyond the runway end, which sheared off the left wing tip. The aircraft then hit a flagpole at the entrance of Green Square and a tree stem, which damaged the ailerons and caused fuel to leak. The flight path continued through a brick wall and into two electric poles. The fourth engine separated from the aircraft 1504 meters from the runway end. The aircraft impacted the ground at a 30-degree nose-down and 30-degree left bank attitude. The impact caused the aircraft to burst into flames, with debris spreading over a distance of 500 meters. The accident resulted in 4 fatalities among the crew and 7 injuries to people on the ground.
Findings
- The aircraft attempted takeoff with the flaps in the retracted position.
- The increase in aerodynamic drag during landing gear retraction caused the aircraft to decelerate to its stall speed.