Higher altitude elevated risk for copter

Above 10,000 feet, the controls feel mushy, engine power fades and the rotors lose lift in the thinning air — making high-mountain evacuations among the most dangerous peacetime missions for military helicopter pilots.

Blinding white slopes only add to the danger.

"When you're against snow like that, it's very difficult to find a hover reference," said Lt. Col. Chuck Foster, director of Alaska Rescue Coordination Center and a veteran HH-60G Pave Hawk helicopter pilot, the same kind of craft that went out of control and crashed on Mount Hood during a rescue operation yesterday.

"Hovering that craft is not an automatic thing, it takes a lot of skill, and without a fixed object to reference, it's hard to hover in one spot," said Foster.

Investigators are still determining what caused the Pave Hawk to go down yesterday.

Peter Leas, a former climbing guide who witnessed the crash while assisting in the rescue, said the pilot told him the wind, blowing at 40 mph, changed directions, causing a loss of power. The pilot, later identified by the Air Force as Capt. Kelvin Scribner, told Leas he then tried to push the chopper away from the rescue scene to minimize injuries on the ground.

One member of the six-person Air Force Reserve crew, Staff Sgt. Martin M. Mills, was in serious condition with a broken wrist and internal injuries at Legacy Emanuel Hospital in Portland.

The others were taken to the hospital with more minor injuries. Three were treated and released, according to a nursing supervisor.

The helicopter, assigned to the Air Force Reserve's 939th Rescue Wing out of Portland, was rescuing critically injured climbers who had fallen into a crevasse near the summit of Mount Hood, Oregon's tallest mountain at 11,237 feet.

The crew carried two of the climbers down the mountainside to a staging area near historic Timberline Lodge, where they were transferred to Oregon National Guard Black Hawk helicopters for the final leg to a Portland hospital.

But as the crew was trying to get into position to pick up a third climber, the craft appeared to lose control and nosed into the mountain, its rotor splintering into pieces. The helicopter tumbled down the snowy slope, stopping when it struck a snow bank at the base of a huge outcropping called Crater Rock.

Built for combat, the HH-60 Pave Hawk helicopter is also the Air Force's premier search-and-rescue craft — performing dozens of air and sea rescues every year.

A highly modified version of the Army Black Hawk helicopter, the Pave Hawk is built to fly in all weather and is known as a comfortable, easy craft to operate.

But at 10,000 feet, an altimeter warning goes on in the cockpit, and performance begins to drop off. The highest rescue operation for the Pave Hawk was 14,500 feet at Alaska's Mount McKinley. Operations at higher altitudes require sturdier helicopters such as the SA-315 Llama, which has plucked people off McKinley at 19,500 feet.

"The HH-60 is a very good helicopter, no question about it," said Foster, who has been involved in dozens of McKinley rescues. "But at higher altitudes, because the air is thinner, you have less power available. The engines breathe air, so taking air away from it is like taking fuel away. And then you have a double whammy because the rotors become less effective because the air is less dense, and you don't get the same lift."

The result, he said, is "things move a little slower. You accelerate slower, you slow down slower."

That means less time to react to changing conditions, such as the wind shift indicated by the pilot in yesterday's crash.

"If you're operating with a reduced margin of performance, your options are also reduced. These are all things that might have come into play," said Foster, a member of the Alaska Air National Guard.

Pilots prepare for this drop in power with months of high-altitude training at the Air Force rescue school at Kirtland Air Force Base in Albuquerque, N.M.

Foster declined to speculate on possible causes of yesterday's crash. He watched in dismay yesterday as news coverage broadcast the crash over and over.

"It was dramatic footage," Foster said. "That must have been quite a ride."

According to the Air Force Safety Center in Albuquerque, there have been nine crashes and 34 fatalities since the craft was introduced in 1982. The last fatalities came in 1998, when two Pave Hawks collided during rescue training in Nevada; 12 died.

Two years ago, a Black Hawk helicopter crash landed at the 11,300-foot level of Mount Shasta in Northern California while searching for a missing hiker. None of the seven people on board was seriously injured.

Still, helicopters rarely go down during high-mountain rescues, said Dave Kreutzer, manager of aviation rescues at Mount McKinley, where about a dozen air rescues occur each year.

"Mountain rescues are out of the realm of normal flying," Kreutzer said. "You're throwing in wind, you have different mountain conditions and then performance drops off. But most of the time you have experienced crews used to that kind of flying."

The 939th is scheduled to be transferred this fall from Portland International Airport to an Air Force Base in Florida. The Rescue Wing will be replaced by an aerial refueling squadron, a move opposed by Oregon officials and the Pacific Northwest congressional delegation.

In addition to mountain rescues in the Northwest, the 939th often is called to sea to pull injured sailors off ships.

U.S. Rep. Brian Baird, D-Wash., said the Northwest delegation argued that mountain rescues need a quick response, and the 939th is located in a perfect spot. Without them, rescues would have to be handled by cash-strapped local agencies.

"These choppers and crews are scarce and tremendously valuable commodities," Baird said.

Ray Rivera: 206-464-2926 or rayrivera@seattletimes.com.

The Associated Press contributed to this story.