> Design and Construction > Automatic Activation Devices and Reserve Static Lines > Automatic Activation Devices > Operation

The CYPRES® system is a barometrically controlled microprocessor that activates a pyrotechnic cutter that cuts the container locking loop. When calibrated to ground level, the barometric sensor activates the unit firing the cutter when the descending parachutist reaches an altitude of approximately 750 feet AGL and exceeds a rate of descent of 115 feet per second. The CYPRES® consists of three parts: (1) the battery and Mprocessing unit, (2) the control unit, and (3) the cutter. [Figure 2-43] The processing unit is generally located in a stowage pouch installed in the reserve container of the parachute system. [Figure 2-44] The control unit is contained in a vinyl pocket located either under the pin protector flap or in the upper backpad area. [Figure 2-45]

Figure 2-43. CYPRES®.

Figure 2-44. CYPRES® container pouch.

Figure 2-45. CYPRES® control unit vinyl pocket.

Figure 2-46. CYPRES® cutter location.

The cutter(s) may be located at the base of the pilot chute or on a flap over the pilot chute. [Figure 2-46] Each parachute system has its own particular requirements, and it is imperative that the rigger have the appropriate manuals for installation.