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Automatic activation devices (AADs) are devices which activate the parachute automatically. Modern systems combine a barometric sensor with a rate of descent sensor so that the system is fully automatic once turned on and calibrated. The activation may be by either pulling the ripcord pin(s) or cutting the locking loop(s), causing the pilot chute to release. Most older models use a mechanical or pyrotechnic pin pulling technique. Newer models use a pyrotechnic loop cutting design. For many years, AADs were primarily used by the military and student parachutists. The designs were bulky, expensive, and, to a degree, inconsistent. The installations themselves were cumbersome and awkward. In the early 1990s a new generation of AADs became available. The CYbernetic Parachute Release System (CYPRES®) uses modern parachute release technology. It is small, reliable, computer based, and uses a pyrotechnic loop cutter. It has an auto-off feature that turns the unit off after 14 hours of operation to conserve power. It also has the ability to calibrate the unit for operation at altitudes other than the calibrating ground level. Based on these concepts, other companies have developed similar systems and as a result, changed the approach to the design and use of AADs. Today, most sport parachutists use an AAD and some countries mandate their use by all parachutists

The following describes the operation and installation requirements of the CYPRES® model AAD. Most other designs are compatible with the CYPRES® installation requirements.