KATHMANDU, Nepal (AP) — Rescuers on Monday found the wreckage of a plane that slammed into a snow-covered mountain in Nepal and burst into flames, killing 18 people, including a child, authorities said.

Moving slowly through thick snow, rescuers walked for 13 kilometers (8 miles) to the crash site. Air traffic control had lost contact with the plane on Sunday afternoon in poor visibility due to snow, rain and fog.

"Our plane was technically airworthy and we believe it was the weather that caused the crash," said Ram Hari Sharma of Nepal Airlines. He said there will be a full investigation.

The state-run airline is often criticized over allegations of corruption and flying old planes. Last year, the European Union banned all Nepalese airlines from flying to Europe because of poor safety records.

The plane had 15 passengers and three crew members. One passenger was Danish, according to the Danish Foreign Ministry, while the rest were Nepalese. The age of the passenger with the infant ticket was not given.

The plane's charred wreckage was flung across a wide area, said police official Bam Bahadur Bhandari. Some victims were identified using documents found in the wreckage, he said.

A helicopter was able to spot the wreckage earlier Monday near Machinelek, about 250 kilometers (160 miles) west of the capital, Katmandu, but they only way to access the remote location was on foot.

The bodies were first picked up using ropes and nets by a smaller helicopter and then taken to a cleared area. They were then moved to a bigger army helicopter and flown to the capital, Katmandu.

Doctors at the Tribhuwan University Teaching Hospital were performing autopsies before releasing the remains.

Police and soldiers were trying to dig a temporary helipad for rescue helicopters. The cockpit voice recorder was also recovered from the crash site, the air rescue office in Katmandu said.

The plane was flying from Katmandu to Jumla, about 400 kilometers (250 miles) to the west, when it made an unscheduled fuel stop in the city of Pokhara, about a third of the way into the journey. The de Havilland Canada-manufactured Twin Otter was 43 years old.

In May, another plane of the same make and model operated by Nepal Airlines crashed while attempting to land at a mountain airstrip in northern Nepal, injuring all 21 people on board.