The pilot of the helicopter that crashed in Theodore Roosevelt National Park while rounding up wild horses had a history of safe flying for more than 30 years, his employer says.

Kathy Gilbert, president of El Aero Services in Elko, Nev., said pilot Ted McBride has been flying for the company for 35 years and before Thursday had never crashed.

He was at the controls when the Bell 206 helicopter crashed near a corral in the park. He and park wildlife biologist Mike Oehler were treated for minor injuries at a Dickinson hospital and released.

"We're very thankful that no one was seriously injured," Gilbert said Friday.

She said McBride's description of the crash was that "he was hovering in the proximity of the corral, and in the process of hovering, his (landing) skid hit a guy (tension) wire and it flipped the helicopter over."

The description is similar to that of eyewitnesses, who said the helicopter was between two fences when it lifted and moved to the side, then pitched to the ground.

The chopper was only a few feet off the ground when the crash occurred. Gilbert said Friday that damage to the aircraft was still being evaluated. The helicopter came to rest on its left side next to the corral fence. Parts of its rotor broke off and flew into the corral when the aircraft hit the ground. No people or horses were hurt.

The horse roundup was called off after the crash. The federal Interior Department is investigating the cause of the accident.

Two investigators were traveling to the park from Boise, Idaho, on Friday. Park Superintendent Valerie Naylor said they should wrap up their investigation over the weekend.

She said the park will be reviewing all of its procedures, but said, "I trust we will continue using helicopters in the future."

"Helicopters are by far the most efficient and safest way to round up wildlife," she said.

Helicopters have been used in park roundups for about 20 years, according to Naylor. She said she knows of no other crashes in the park's history.

Naylor said McBride was certified through the Interior Department to do contract work, and had recently helped with a bison roundup in South Dakota's Wind Cave National Park. McBride helped with bison roundups at the North Dakota park in 2004 and 2005, she said.

A helicopter pilot must meet certain standards to be certified with the Interior Department, said Jeff Olson, a National Park Service spokesman. The person must have 1,500 hours as a pilot in command; 100 flying hours within the past 12 months, with at least half of them as pilot in command; and a minimum of 25 hours and the required schooling as pilot in command of the make and model of aircraft the person is flying.

"This has been our standard for at least 18 years," Olson said. "We just don't contract with companies that have entry-level pilots."