Background
The aircraft, a twin-engine model, was operating a scheduled flight from Lamidanda Airport to Kathmandu. Departure occurred at 1508 local time. Initial clearance allowed a climb to 10,500 feet. Shortly after, ATC revised the clearance, instructing the flight to maintain 8,500 feet due to other traffic.
Flight and Decision
The captain disagreed with the ATC instruction and continued climbing. The copilot, who was the pilot in command (PIC), urged the captain to comply. Ultimately, the captain authorized the copilot to descend to the assigned altitude of 8,500 feet. This decision was made despite the acknowledged risk of operating in mountainous terrain at that altitude.
Accident Sequence
A few minutes after the descent, the aircraft entered cloud cover. While in these conditions, the right wing impacted the ground. The aircraft subsequently crashed in a rocky area on Palunge Hill, near Okhaldhunga. The wreckage was found the following morning.
Aftermath
The aircraft was destroyed by the impact. All 22 persons on board perished. At the time of the accident, instrument meteorological conditions (IMC) were present, characterized by low visibility and cloudy skies.
Probable Cause
According to the official investigation, the accident was caused by the crew's unwise decision to descend without accounting for the hazardous mountain terrain. The event was described as controlled flight into terrain.