Flight Details
Alliance Air flight CD-7412 departed Netaji Subhash Chandra Bose International Airport, Kolkata, at 0651 hrs. on July 17, 2000, bound for Patna, Lucknow, and Delhi. After a normal departure from Runway 01R, the aircraft climbed to flight level 260 (FL260) on track to Patna via airway W52.
Sequence of Events
Kolkata Radar controlled the aircraft from 0652 to 0659 hrs., after which it was handed over to Kolkata Area Control Centre. The aircraft reported over waypoint SAREK at FL260 at 0712 hrs. and switched to Patna Control, noting no reported traffic for descent. At 0713 hrs., the crew contacted Patna ATC with an estimated time of arrival of 0736 hrs. Patna ATC cleared the aircraft for the PPT VOR ILS/DME ARC approach to Runway 25. The controller provided the 0650 hrs. METAR: calm wind, visibility 4000 meters, haze, broken clouds at 25000 feet, temperature 29°C, dew point 27°C, QNH 996 hPa.
The aircraft was cleared to descend to 7500 feet and to report 25 DME from PPT VOR, which it did at 0726 hrs. It then descended to 4000 feet on QNH 996 hPa and was asked to report 13 DME for the ILS/DME ARC approach. At 0728 hrs., the aircraft reported commencing the arc. It reported crossing the lead radial 080 at 0731 hrs. and aligning with the localizer. The crew was then instructed to descend to 1700 feet on QNH 997 hPa and to call established on the localizer.
At 0732 hrs., the aircraft informed ATC that it intended to perform a 360-degree turn because it was high on approach. ATC asked if the airfield was in sight; receiving an affirmative reply, ATC cleared the aircraft to report on finals after the 360-degree turn. The crew acknowledged, and this was the last radio contact.
Immediately after, the air traffic controller saw the aircraft in a normal descent aligned with Runway 25 but appearing high on approach. The aircraft then made a steep left turn, lost altitude suddenly, and disappeared behind trees. The controller saw a large column of smoke rising from the Gardani Bagh area and initiated crash response.
Occupants and Casualties
All six crew members and 49 passengers were killed; five people on the ground also lost their lives. Three passengers survived with serious injuries.
Investigation Findings
The official investigation determined that the accident was caused by loss of control due to human error by the aircrew. The crew did not follow the correct approach procedure, resulting in the aircraft being high on approach. They kept the engines at idle thrust and allowed the airspeed to decrease below normally permissible values. They then maneuvered with high pitch attitude and rapid roll reversals, which triggered the stick shaker stall warning. At that point, the crew initiated a go-around procedure instead of the approach-to-stall recovery procedure, leading to an actual stall, loss of control, and impact with the ground.