The final report, investigated by the Indian Directorate General of Civil Aviation, concluded that the cause of the crash was due to pilot error.

The aircraft was on approach with its engines at idle thrust and the crew made several maneuvers with high-pitch attitude.

Two Pratt & Whitney JT8D/17A engines powered the aircraft, each developing approximately 16,000 lbf (71 kN) of thrust at sea level.

During the left turn, the stick shaker activated, warning the crew on the impending stall condition.

The aircraft continued to bank, losing its altitude and eventually grazed trees and a single-storied house in a government residential housing estate, crashing in a government residential colony behind Gardani Bagh Girls School at 07:34 a.m.[3][1] Plumes of smoke immediately appeared from the last area where the aircraft was last seen.

Airport officials and police were met with anger from locals due to the chaotic situation.

The situation finally came under some control after multiple jawans and military officers were deployed to the area.

One passenger, a male teenager, managed to survive unscathed from the crash and was able to walk away from the wreckage.

[8] The aircraft itself had been involved in an accident in January 1986 in which one of its wings had accidentally grazed the ground, causing substantial damage.

The technical logs, however, revealed that the damage was repaired in immediate effect with a "satisfactory result".

[1] Just two weeks before the crash, the British Foreign Office had warned Britons not to board Alliance Air following the withdrawal of a service contract by Rolls-Royce.

They should have started their descent to 2,000 feet (610 m) while commencing the turn but the aircraft remained at the same altitude and heading, even though two minutes had passed since the message was sent from the ATC.

The crew tried to make a zig zag motion in order to lengthen their approach path, thus gradually decreasing their altitude.

The aircraft had just crossed the lead radial at an altitude of 3,000 feet (910 m) and was just 3.5 nautical miles (4.0 mi; 6.5 km) from the distance measuring equipment (DME).

The correct procedure stated that an aircraft should have been at an altitude of 2,000 feet (610 m) and was 11 nautical miles (13 mi; 20 km) from the DME while it was crossing the lead radial.

[1] The aircraft crossed the extended runway centre line and entered a zig-zag motion again, first to the left and then to the right.

During the entire sequence, from the start of the zig-zag until 15 seconds before the crash, the engines remained at idle position.

The reason why the engines were set at idle was not clear, though investigators suspected that it was due to their high altitude for an approach.

As per the approach chart, the aircraft should have been at an altitude of 610 to 650 feet (190 to 200 m) while it was at a distance of 1.2 nautical miles (1.4 mi; 2.2 km).

The low speed of the aircraft caused the activation of the stick shaker, warning the crew on the impending stall condition.

When confronted by a stall, the crew should have applied full engine thrust and reduced the aircraft's nose pitch.

The switching of the flap to 15 degree caused a substantial loss of lift due to the reduction of upwards airflow.

Investigators revealed that the presence of tall trees from a nearby zoological garden posed risks to all pilots who intended to land at Runway 25.

Pilots usually stay above the normal glide path until just before the threshold, resulting in late touch down.

While the trees didn't pose threat to normal flights in daytime, investigators stated that the presence of tall trees within the approach path would leave no margin of error for pilots who intended to land in Patna at night, during bad weather, on a wet runway or with an aircraft system malfunction.

The presence of road near the runway caused the threshold to be displaced by 400 ft.[1] The final report of the crash was published in April 2001, 9 months after the accident.

They had kept the engines at idle thrust and allowed the air speed to reduce to a lower than normally permissible value on approach.

Charges included were "culpable homicide not amounting to murder" and "rash driving or riding in a public place.

[10] Even after the official final report was published, most residents who lived near the crash site, along with the relatives of those who perished in the crash, believed that ATC error was the cause of the accident, claiming that the decision to put the blame on the pilots was "a very easy choice" and even implied that the decision was a cover-up attempt.