Military parachuting has undergone tremendous changes since World War II when more than 20,000 paratroopers dropped into German-occupied Holland as part of the D-Day invasion called Operation Market Garden. The D-Day paratroopers used circular silk-made canopies that employed a static line that opened the chute automatically as the soldier jumped from the airplane.
Today’s military employs two distinctly different parachuting techniques: HALO (high altitude, low opening) and HAHO (high altitude, high opening). Both methods deploy the parachutist from an aircraft traveling at a high altitude. Traditional deployment altitudes, such as in Operation Market Garden and other mass drops of paratroopers since then, usually are between 500 to 2,000 feet. Low altitude drops mean that paratroopers spend less time in the air exposed to enemy attack, and the airplanes that carry them can fly under enemy radar.
HALO and HAHO operations usually deploy personnel anywhere from 15,000 feet to 35,000 feet. Such high altitudes do not lend themselves to the mass deployment of large numbers of paratroopers. Instead, these modern methods are reserved for the covert insertion of special forces or special operations personnel.
HAHO parachutists use specially designed square canopies that can be accurately steered by the user and travel forward at high speeds. The forward movement and steerable character of the canopies allow troops to deploy their chutes at high altitude out of range of the enemy and glide long distances to their intended landing zone. Because the aircraft can travel far outside of enemy airspace, there is less risk of detection.
HALO jumpers use a free-fall technique that causes them to plunge toward the landing zone at high speeds before pulling their ripcord at somewhere between 1,000 and 2,000 feet. The free-fall technique offers the parachutists the opportunity to drop silently toward a landing zone without a deployed canopy that can be detected by observers on the ground. The HALO technique has proven to be quite effective when delivering supplies and equipment as well as personnel to targeted drop zones. The high rate of descent during free fall coupled with the low altitude at which the chute is deployed make it difficult for conventional radar and people on the ground to detect the jumper.
High altitude parachuting carries with it more risks than are usually associated with the inherently dangerous activity of jumping out of airplanes. Jumps that originate above 22,000 feet require that the parachutist carry oxygen. Jumpers risk falling prey to hypoxia which is the deprivation of oxygen to the body. Hypoxia can cause a person to lose consciousness and, if unable to open the parachute, die.
Another risk associated with HALO and HAHO jumps is the subfreezing temperatures that jumpers may experience at high altitudes. Temperatures at 35,000 feet can be minus 50 degrees Fahrenheit. Special cold-weather clothing made for high altitude parachuting helps to minimize the effects of low temperatures.
