MILITARY CYPRES USER'S GUIDE
Page 22
Airtec GmbH
You have to change the reference air pressure whenever
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the airfield or the elevation at which you switch CYPRES on and the
intended drop zone are at different elevations
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or if you need an immediate arming of the device.
4.4
Changing altitude reference
All Military CYPRES are available as Relative Adjustment or Absolute Adjustment
version. Military CYPRES units using the relative adjustment method (pressure
difference between switch on and DZ location) are not particularly marked. Military
CYPRES units using the absolute adjustment method on the other hand, are marked
with the black letters ‘Abs. adj.’ above and below the LED on the control unit
4.4.1
Changing altitude reference (relative adjustment method)
The unit can even be switched on in an aircraft provided the air pressure is constant
during the whole setting. Prior to making the altitude adjustment it is definitely necessary
to know two absolute air pressure values:
1. the absolute air pressure in the plane i.e. the point you are at, and
2. the absolute air pressure at the drop zone.
When asking the pilot about the air pressure it is very important that you obtain the
absolute air pressure inside the cabin and at the landing site (not the sea level
pressure or the altimeter setting). (Alternatively, if you do not, for whatever reason,
know the absolute air pressures, the altitude adjustment can be carried out using a
special calculator. With this procedure, however, small inaccuracies are unavoidable.
For details see chapter 4.4.1.2)
Military CYPRES with
relative pressure adjustment
Military CYPRES with
absolute pressure adjustment
The altitude adjustment using air pressure differences is carried out as follows:
To do the adjustment you conitue tp press the button of the control unit after you turn
your CYPRES on. CYPRES will continue with its self-test, and once it has finished, it
will display air pressure differences in steps of 1 hPa (1 hPa = 1 mbar).
The display changes in single steps starting with 1, the little arrow pointing alternately
upwards and downwards for a short time. When the 1 appears on the display the
CYPRES asks whether the air pressure at the intended drop zone is 1 hPa lower
than at the setting location. When the 1 appears on the display CYPRES asks
whether the air pressure at the intended drop zone is 1 hPa higher than at the setting
location. The display changes to 2 , then to 2 , etc. In chapter 4.4.1.1 you will find
