In the military context a drop zone is any designated area where personnel and or equipment may be delivered by parachute or, in the case of certain items, by free drop. The specific parameters for DZ’s may vary between militaries. For example,
NATO’s STANAG normative regulation for drop zone operation and engagement differs from the parameters set out by the
United States Marine Corps. STANAG, 1993 Drop Zone chapter considers a range of factors involved in appropriate drop engagement. Firstly, the airspeed of engagement over the drop zone is used to estimate the time to the landing at the drop zone. Drop altitude is another measurable variable which is calculated between the aircraft and the ground, taking into consideration the personnel, container delivery as well as the weight of the equipment delivered. The time between jumps is also considered which depends on the number of jumpers. Then, the methods of delivery are provided; there are usually three methods: low velocity to decrease airspeed most for sensitive equipment and personnel, high velocity for supplies and free drop. DZ obstacles include trees, water, powerlines or other conditions that may injure parachutists or damage equipment. Access to and size of DZ are calculated with regards to the obstacles and the number of jumpers; for example, one jumper the size of DZ should be at least 550m by 550m. Another important variable which determines the effectiveness of a DZ is the support team (DZST) servicing it. STANAG regulation suggests that there should be at least two trained members of personnel servicing a DZ. Primary missions of the DZST include wartime CDS drops to battalion or smaller size units, and peacetime
visual meteorological conditions drops involving one to three aircraft for personnel, CDS, and heavy equipment. == Recreational drop zone ==