This site contains some very interesting accounts and pictures of the rescue activities on Mt McKinley, Alaska by the
"Denali Lama".
The highlight of many of the rescues is the use of the Screamer Suit, into which the individuals climb, before utilising the integral harness to attach themselves to the longline hook! They are then slung off the mountain - check out the British climbers picked off at 19,000 feet!
Jim Hood has been flying this contract for many years now, initially for Rocky Mountain, and currently for Evergreen. In addition to these rescues, he also had an engine shut down at 14,000 feet, when he landed to pick up an injured climber. The engine lit-off on the third attempt, not before Jim had realized that there was a very high likelihood that they were about to die on the mountain - lucky escape!
http://classic.mountainzone.com/climbing/denali/rescue/