The Tara Air plane bound for Kathmandu carrying 19 passengers crashed in dense cloud in December shortly after taking off from a small airstrip 140 kilometres (90 miles) east of the capital.[break]
Investigator Rabindra Kumar Sherchan said the plane descended on the instructions of air traffic control to avoid a helicopter in the area, but it then clipped a hill top with its left wing.
"The cause of the accident was the unwise decision taken by the crew to descend without taking the harsh mountain terrain into consideration," said Sherchan, a member of a government-commissioned investigation board.
He said there was also confusion between the pilot and the co-pilot, with the latter controlling the flight as the aircraft entered the cloud.
The 27-year-old Canadian-built Twin Otter plane was carrying Buddhist pilgrims returning from a Buddhist holy site in the area.
One passenger was identified as an American citizen of Tibetan-origin and the other 18 were from Bhutan.
Officials from Tara Air, a privately owned domestic airline that runs a service to the Himalayan nation´s remote destinations, were not available for comment.
Aviation accidents are relatively common in Nepal, which has a very limited road network. Remote areas are accessible only on foot or by air.
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