High-altitude military parachuting
High-altitude military parachuting (or military free fall (MFF)) is a method of delivering military personnel, military equipment, and other military supplies from a transport aircraft at a high altitude via free-fall parachute insertion. Two techniques are used: HALO (high altitude - low opening) and HAHO (high altitude - high opening).
In the HALO technique, the parachutist opens his parachute at a low altitude after free-falling for a period of time, while in the HAHO technique, the parachutist opens his parachute at a high altitude just a few seconds after jumping from the aircraft. Military HALO techniques date back to 1960, while in recent years, the HALO technique has been practiced by civilians as a form of skydiving.
In military operations, HALO is used for delivering equipment, supplies, or personnel, while HAHO is generally used only for personnel. In typical HALO/HAHO insertions the troops jump from altitudes between 15,000 feet (4,600 m) and 35,000 feet (11,000 m).