Nepal said on Saturday an error by a "panic-stricken" pilot likely caused the crash of an Everest-bound plane that killed all 19 on board moments after it hit a large bird.
The twin-propeller Sita Air plane had just taken off on Friday from Kathmandu and was headed to the town of Lukla, the gateway to Mount Everest, when it plunged into the banks of a river near the city's airport around daybreak.
Its right engine had burst into flames after a bird-of-prey thought to be an eagle flew into it and the pilot banked back towards the airport.
But senior aviation ministry official Suresh Acharya told AFP the plane had then turned too sharply because it had not gained enough altitude.
"The preliminary finding of the Civil Aviation Authority notices unusual manoeuvring during the take-off and the pilot communicated to air traffic control the aircraft was hit by a bird," Acharya added.
"But a plane crash does not occur simply just because its engine was hit by a bird," he said, noting incidents when one engine of a twin-engine aircraft had failed and the plane was still able to land safely.
"The pilot may have been panic-stricken," he added, and "made a steep narrow turn instead of forming a wider radius required to bring the malfunctioning aircraft back to the runway".
Acharya, a member of a government commission due to report on the cause of the crash within three months, said the pilot should have gained more height before trying to return to the airport.
The foreign victims had arrived in Nepal on Wednesday and had been slated to begin trekking towards Everest Base Camp on Saturday accompanied by local guides on an expedition organised by English firm Explore Worldwide.
Student Wu Hui, 27, of California, was initially named among five Chinese dead in the crash, which also killed seven Britons, but Sita Air said his passport recovered at the crash site revealed he was an American of Chinese origin.
"One American citizen of Chinese origin was among the 12 foreigners who died in the Sita Air crash yesterday. Seven Britons, four Chinese and seven Nepalis including three crew members are the other deceased in the crash," spokesman Deependra Shahi said.
"The trekking agency is in touch with us and some relatives have arrived Kathmandu to collect the body of the deceased Britons. We are expecting to be in touch with the Chinese side too for the handover of the bodies."
Police said the victims were piled up at the cockpit end of the wreckage, the Kathmandu Post reported, indicating they had either failed to fasten their safety belts or took them off before hitting the ground.
"We have taken out the data recorder and handed it over to the civil aviation authorities. The rescue work at the site has ended," national police spokesman Binod Singh told AFP.
"It has been difficult to identify the bodies and DNA tests may be carried out before they are handed over to the relatives."
The youngest British victim was Ben Ogden, a 27-year-old Oxford University graduate who recently qualified as a solicitor and was a rising star at a London law firm.
His father Andrew was quoted in Britain's Daily Telegraph as saying his son wanted the trip to be "his big adventure" before he "knuckled down to some serious work" and life with his girlfriend of eight years.
Other victims include Timothy Oakes, a 57-year-old secondary school adviser, and his friend Stephen Holding, a 60-year-old retired science teacher.
Building contractor Vincent Kelly, 50, and his brother, property developer Darren, 45, were also killed along with Chris Davey, 52, an electronics engineer, and Ray Eagle, 60, a marathon runner.
It was the sixth fatal crash in Nepal in two years and has raised fresh questions about air safety in the impoverished Himalayan country, home to challenging weather, treacherous landing strips and lax safety standards.
The crashes have claimed the lives of close to 100 people, according to an AFP tally.
British Prime Minister David Cameron on Friday called the crash "a horrific incident" and said: "I feel for the families concerned."
Nepal has a poor road network, meaning many tourists, pilgrims and climbers rely on the country's 16 domestic airlines and 49 airports to reach remote areas.