Accident Description
The aircraft was cleared for takeoff and began its departure roll with the flaps retracted, according to flight data recorder information. It rotated at 280 kph (151 knots) and became airborne at 288 kph (155 knots) with an angle of attack of about 8–9 degrees. Tire marks on the runway indicated that the aircraft passed the end of the runway, with the main tires impacting runway end lights and continuing beyond the paved stopway.
Sequence of Events
Climbing through 15 feet, the pilot flying commanded the landing gear up and increased the pitch angle. The angle of attack rose above 10 degrees while the gear doors opened for retraction, increasing drag. The aircraft began to slow, reaching 305 kph (164 knots), which was the stall speed for the takeoff weight. The left wing began to stall as the angle of attack increased to 17 degrees at a height of 5–7 meters (15–23 feet). The pilot flying attempted to counter the left roll by fully applying left aileron, which deployed the right wing spoilers, and applied right rudder input.
The pilot flying instructed the flight engineer not to retract flaps, indicating that neither pilot was aware the flaps were up. The flight engineer then selected the flaps down. At a speed of 300 kph (162 knots) and with no altitude remaining, the aircraft entered an unrecoverable stall.
The left wing struck a high-voltage mast approximately 1200 meters past the runway end at a height of 5.4 meters (18 feet), shearing off the left wing tip. It then contacted the flag post at the entrance of the Green Square. The left wing struck the stem of a tree at a height of about 40 cm (1.3 feet), separating the ailerons and causing fuel to spill from the left wing. The aircraft broke through the eastern brick wall of Green Square, collided with two electric poles, causing engine number 4 to separate 1504 meters from the end of the runway. It impacted the ground at a 30-degree nose-down attitude and 30-degree left bank.
Debris was distributed over a length of more than 500 meters, and the aircraft burst into flames. All four crew members perished in the crash. Four people on the ground received serious injuries, and three others received minor injuries.
Official Findings
The following findings were identified:
- No checklist was used during any phase from engine start, taxi, and takeoff.
- The operating company did not keep records of the crew's flying experience; they had joined about four months before the accident.
- Engine number 1 showed only 96.2% N1, delivering less thrust than the other three engines.
- Engine number 4 showed a 30° higher exhaust gas temperature than the others, indicating unsatisfactory condition requiring the temperature limiter to be switched off to deliver needed thrust.
- According to the FCOM, the aircraft required 2,850 meters takeoff distance at 188 tons takeoff weight with flaps at 30° and slats at 14°. The clean aircraft lifted off after rolling 2,380 meters, a short distance for that weight and temperature of 27°C.
- The automatic configuration warning, which activates at 70 ± 15 kph if flaps are not extended, did not activate during the takeoff run; it could be switched off or malfunctioned.