BOZEMAN, Mont. -- For more than 20 years, Mike Carisch has been a friend and colleague to Perry Krinitt.

On Tuesday, Carisch lost his friend in a helicopter crash in Kamiah, Idaho. Krinitt was piloting a helicopter when it went down killing him and two other people on board.

The Idaho Department of Fish and Game chartered the chopper to study salmon fisheries.

As a tribute to his friend, Carisch decided to do something that he thinks his friend would appreciate it. "I knew he would like it, that's why I did it," Carisch said.

He brought out his own helicopter from his Bozeman home, and hit the skies, towing a large American flag beneath him.

The helicopter slowly crawled above the runway of the Gallatin Field Airport with the American flag flowing in the wind. For about 20 minutes, Carisch flew the flag all around the Gallatin Valley.

He circled around Bozeman, and finally ended up at his own home west of Bozeman.

Carisch said it was important to remember his friend because not only did they share piloting in common, but both men were also firefighters. He said he had seen it done before as a way of remembering pilots, but some onlookers at Gallatin Field Airport said they had not seen anything like it before.

Carisch said he and his friend took different paths to becoming pilots, but over the years they always stayed in touch, and were always friends.

Krinitt was 43 when he died. His family said he lived in Bozeman with his wife.

Two other people were also killed on the flight. Larry Barrett and Danielle Schiff were both Fish and Game Biologists.

Experts think that a mechanical malfunction caused the aircraft to go down.

No one on the ground was injured in the accident.