AAD Vigil Cuatro User Manual page 17

Conclusion:
If the Vigil Cuatro is set in "PRO" mode, it will activate at a average altitude of 840 ft or 256 m above
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the ground, at a falling speed of 115 ft/sec (78 mph or 35 m/sec.) or greater.
It is well accepted that this minimum activation level must be guaranteed whatever the position of the skydiver.
If the skydiver is falling in a back to earth position, the reading will reflect the correct pressure, since the
sensor is not influenced by a depression (burble), but if the skydiver is falling face to earth, then the sensor
located in the depression zone (burble) will read a pressure up to 10mbar lower, or an altitude ±260 ft or ±79
m above the real altitude, and will, in this case, activate later, or ±260 ft or ±79 m lower, i.e. at an actual
altitude of 580 ft or 177 m above the ground level, which would be too low.
Therefore, a compensation of +260 ft or +79 m above the nominal activation altitude has been integrated
into the software. For example in "PRO" mode, a programmed activation altitude of 1100 ft or 335 m has been
set to ensure that, notwithstanding the skydiver's body position, activation will always be at a minimum altitude of
840 ft or 256 m (actual altitude) above the ground level.
Remarks:
• In a test chamber, the activation in "PRO" mode will be at 1100 ft (840 ft + 260 ft) or 335 m
(256 m + 79 m) as there is no depression zone (burble).
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