Kathmandu - For Captain Surendra Kumar Kunwar, the early morning flight to Lukla from Kathmandu was a routine affair like dozens he had made on the route during his flying career.

The weather had been clear in Kathmandu with the mountains clearly visible in the morning sun as he prepared to take off Wednesday to one of the busiest airports in the country.

But it would not be a regular flight, and only one person on board would survive after the Twin Otter plane crashed in fog 30 minutes after takeoff. Little did the pilot know that he would be the only one to return.

The crash came a day before the end of Nepal's biggest festival, Dashain, which is marked by reunions with family and friends. The deaths of both Nepalese and foreign tourists have cast gloom over the celebrations.

For the families of the Nepalese killed in the crash, the festival has stopped.

Trekking guide Govinda Sharma was on the flight to make arrangements for German tourists for a trek in the Mount Everest region. He had taken leave of his family promising to return.

"We kept the offering for the Dashain festival for him for after he returned," his sister Goma said at his house on the outskirts of Kathmandu. "We will not be celebrating the festival now, and we are throwing out the offerings."

The German tour group was on a 17-day trip to Nepal to trek around Mount Everest and Gokyo Peak. There were several couples in the group.

They were flying into Lukla at the start of a busy day for the airport about 150 kilometres north-east of Kathmandu. Several flights had already landed and taken off without incident.

"I was watching the aircraft coming in to land and taking off," said Suraj Kunwar, a Kathmandu-based journalist on holiday in Lukla.

"I watched the Yeti Airlines plane coming in to land, but clouds rose up and obscured the view," Kunwar said. "Next thing I heard was a loud noise, and I turned around to the end of the runway and I could see fire."

After that, chaos ensued, and tourists waiting for their own flights left their breakfasts or whatever they were doing, Kunwar said.

"Some people were crying, others were shouting," Kunwar said. "There was genuine sense of fear. I ran toward the wreckage trying to film the accident. I couldn't because my hands shook too vigorously."

"There wasn't much anybody could do to save the people inside the plane as the whole fuselage was on fire," Kunwar said. "Local people rushed to see the crash, and many just stood silently or sobbing, watching the plane burn with a sense of helplessness."

Lukla airport, situated on a hillside 2,757 metres above sea level, is considered one of the most dangerous in the world.

Some said the crash was a disaster waiting to happen at one of Nepal's airports. The country has dozens of similar airstrips, many without an air traffic controller to guide the planes.

"Most of the airstrips and airports we service are in hilly or mountainous areas," said Vijay Shrestha, executive director of Yeti Airlines. "Many airstrips are carved out on a mountainside and are not even paved. It is dangerous to service these routes."

Nepalese authorities said the reason for the crash was poor visibility. Weather is one of the biggest concerns for planes operating out of mountain airports.

"The weather can be clear now, and the airport could be covered in thick fog just a minute later with near-zero visibility," said Yetin Giri, a pilot for the state-owned Nepal Airlines.

"In many airstrips across Nepal, we don't even have an air controller to guide us in, and we have to rely on a visual approach without the knowledge of surface wind of other conditions," Giri added.

"Despite the dangers, it is our job to fly, and we will continue doing that," Giri said.