When you’re in need of a rescue the approaching thump-thump-thump of rapidly rotating blades is a joyous sound. To give the helicopter rescue the greatest chance of success, a suitable landing zone will have to be found. The ideal landing zone should not require a completely vertical landing or takeoff, both of which reduce the pilot’s control. The ground should slope away on all sides, allowing the helicopter to immediately drop into forward flight when it’s time to take off. Landings and liftoffs work best when the aircraft is pointed into the wind because that gives the machine the greatest lift. The area should be as large as possible, at least 60 feet across for most small rescue helicopters, and as clear as possible for obstructions such as trees and boulders. Clear away debris (pine needles, dust, leaves) that can be blown up by the wash of air, with the possibility of producing mechanical failure. Light snow can be especially dangerous if it fluffs up dramatically to blind the pilot. Wet snow sticks to the ground and adds dangerous weight. If you have the opportunity, pack snow flat well before the helicopter arrives—the night before would be ideal—to harden the surface of the landing zone. Tall grass can be a hazard because it disturbs the helicopter’s cushion of supporting air and hides obstacles such as rocks and tree stumps.
To prepare a landing zone, clear out the area as much as possible, including removing your equipment and all the people except the one who is going to be signaling the pilot. Mark the landing zone with weighted bright clothing or gear during the day or with bright lights at night. In case of a night rescue, turn off the bright lights before the helicopter starts to land—they can blind the pilot. Use instead a low-intensity light to mark the perimeter of the landing area, such as chemical light sticks, or at least turn the light away from the helicopter’s direction. Indicate the wind’s direction by building a very small smoky fire, hanging brightly colored streamers, throwing up handfuls of light debris, or signaling with your arms pointed in the direction of the wind.
The greatest danger to you occurs while you’re moving toward or away from the helicopter on the ground. Never approach the rear and never walk around the rear of a helicopter. The pilot can’t see you, and the rapidly spinning tail rotor is virtually invisible and soundless. In a sudden shift of the aircraft, you can be sliced to death. Don’t approach by walking downhill toward the helicopter, where the large overhead blade is closest to the ground.
It is safest to come toward the helicopter from directly in front, where the pilot has a clear field of view, and only after the pilot or another of the aircraft’s personnel has signaled you to approach. Remove your hat or anything that can be sucked up into the rotors. Stay low because blades can sink closer to the ground as their speed diminishes. Make sure nothing is sticking up above your pack, such as an ice ax or ski pole. In most cases someone from the helicopter will come out to remind you of the important safety measures.
One-skid landings or hovering while a rescue is attempted are solely at the discretion of the pilot. They are a high risk at best, and finding a landing zone and preparing it should always be given priority.
Buck Tilton (Wilderness First Responder: How to Recognize, Treat, and Prevent Emergencies in the Backcountry)