WELLINGTON, New Zealand – Guy Cotter was so concerned about the safety of Sherpa guides and porters through Mount Everest’s notorious Khumbu Icefall that he and another commercial guide operator hatched a plan: Before this year’s climbing season began, they would use helicopters to transport 4 tons of equipment above the icefall.

Nepal-based Simrik Air backed the plan and hired New Zealand pilot Jason Laing, an expert in hauling loads using long cables. But in January, the answer came back from Nepalese authorities: Permit denied.

Three months later, Laing put his expertise to use. But not hauling gear. On April 18 came Everest’s worst disaster, in which 16 Sherpas were killed in an avalanche at the icefall. Laing made flight after flight that day, using his long cables to rescue four injured Sherpas and haul out 13 bodies. The three others are buried under heavy snow and ice.

“It was tough,” Laing said. “I just had to get on with it.”

Among those killed were three Sherpas hired by Cotter’s company, Adventure Consultants.

It’s not the first time Nepal has rejected proposals to reduce the need for Sherpas to lug equipment up and down the icefall. But Cotter and other commercial operators say they hope the avalanche will prompt long-overdue safety improvements.

“It’s a shame it takes a major tragedy to get us to that point,” Cotter said.

The Khumbu Icefall is considered the most dangerous terrain of the climb. It is a river of ice, a half-mile or so of constantly shifting glacier punctuated by deep crevasses and massive overhanging blocks of ice called seracs that can be as large as 10-story buildings. The icefall can move 6 feet in just one day. Crossing it can take 12 hours. Ropes can be snapped by the moving ice, ladders broken.

Cotter, a New Zealander, is a well-known operator at Everest. He first climbed the mountain in 1992 and has owned and run Adventure Consultants since 1996. This year was typical: He had 10 clients from Britain, Japan, the U.S. and Iceland, among other places, and employed 44 Sherpas as porters, guides and cooks. His company was one of several seasoned operators at the mountain.

Simrik Air Operations Manager Siddartha Gurung said that before the permit was denied, his company had been preparing to make about 30 flights to Camp 1, above the icefall, carrying enough weight to eliminate 300 Sherpa trips.

“That’s 10 potential lives saved on every trip,” he said, adding that he believes the death toll would have been lower if the permit had been approved.

“The government is like this in Nepal; they’re very bureaucratic, and their decisions don’t make sense,” Gurung said. “They don’t have a good understanding about what really happens in the mountains.”

Maddhu Sudan Burlakoti, head of Nepal’s mountaineering department, refused to comment about its decision to deny the permit.

In the past, Nepal’s government has cited environmental concerns as a reason to avoid using helicopters at Base Camp and above.

Some climbers also have complained the craft would detract from the purity of their experience. Sherpas, too, worry it may mean less work for them. A top guide can earn $6,000 in a three-month climbing season, nearly 10 times Nepal’s $700 average salary.

Flying helicopters in such thin air comes with its own risks. Base Camp is at an altitude of 17,600 feet, while Camp 1 is at about 19,500 feet.

“It’s getting very near the limit,” Laing said. “It’s high risk, and there are variables. It has its own climate. It can be warm or windy or turbulent.”

Using helicopters is not the only change Cotter has pushed for. He said he and other operators repeatedly have asked to store gear year-round at Camp 2, rather than the current system, which requires them to remove everything from the mountain each year. He said large dining tents and other items could be broken down and stored safely at the camp.

Cotter said the two changes he has advocated would easily cut in half the number of Sherpa trips through the icefall.

Todd Burleson, president and owner of Seattle-based Alpine Ascents International, said he also has tried to limit the loads taken by Sherpas up the icefall.

“We have expressed desire to store gear at Camp 2, but this has been denied,” he wrote in an email from Nepal, where he has been trying to comfort the families of five Sherpas employed by his company who died in the avalanche.

Burleson said he also believes it would make sense to use helicopters to transport gear up the mountain before the spring season began, though he cautioned that too many flights could end up being risky.

He said improvements also need to be made to the route up the icefall, which currently is administered by Sherpa teams called Icefall Doctors that are managed by a nonprofit group, the Sagarmatha Pollution Control Committee. Each climber pays the committee $600 to use the route.

“We also need to address the SPCC in fixing the icefall. This was removed from our hands many years ago, so we must wait for them to decide which way the route goes, etc. This is not the best way,” Burleson wrote. “They need better training, equipment and staff to make this route safer.”

Kapindra Rai, an SPCC official, disagreed, saying it closely monitors the route throughout the climbing season, employs expert staff and regularly replaces ladders and ropes.

“The Icefall Doctors have years of experience, and they are the experts in the business,” he said. “It was an avalanche and not our route that is to be blamed.”

Many believe climate change is contributing to making the icefall more treacherous.

Nepalese authorities in recent weeks have decided to finally allow the two things that Cotter and other operators have been pushing for. They allowed helicopters to retrieve gear from Camp 1 rather than have Sherpas carry it back down the icefall. And they are allowing operators to keep some gear at Camp 2 over winter.

In both cases, Nepalese authorities say they’re allowing one-time exemptions because of the avalanche. Many operators, however, hope the changes will become permanent.

“The icefall is not improving. It’s getting worse and worse,” said Gurung, the helicopter manager. “From now on, it’s the only option.”

Associated Press writer Binaj Gurubacharya in Katmandu, Nepal, contributed to this report.