MILITARY CYPRES USER'S GUIDE
Airtec GmbH
Page 27
The unit can even be switched on in an aircraft provided the aircraft climb or
descend rate does not exceed 5 m/s (1000 ft/min) during the whole setting. To be
able to make the altitude adjustment it is definitely necessary to know the absolute air
pressure at the drop zone.
When asking the pilot or the Air Traffic Controller about the air pressure it is very
important that he gives you the absolute air pressure. (Alternatively, if you do not,
for whatever reason, know the absolute air pressure, the altitude adjustment can be
carried out using a special calculator. With this procedure, however, small inaccuracies
are unavoidable. For details see chapter 4.4.2.2)
The speed with which the numbers change is not constant. If the button is pressed
the numbers change in the beginning at uniform slow speed, allowing one to make
precise 1 hPa adjustments. If the button is kept pressed however the rate of change
of the numbers speeds up providing the ability to enter a large pressure value. If the
button is released and pressed again, the numbers change again at the slow rate.
The procedure of pressing, releasing and pressing again can be repeated as often
as required. It is important to note that if the button is released for longer than 8
seconds, CYPRES will assume the process has been completed and no further
adjustment will be possible. If this is necessary CYPRES would have to be switched
off and the whole process re-started. After the 8 seconds the selected air pressure
remains on the display and the CYPRES can be switch off like usually.
During these 8 seconds the CYPRES cannot be switched off.
4.4.2
Changing altitude reference (absolute adjustment
method)
The altitude adjustment by entering the air pressure is carried out as follows:
To do the adjustment you leave the button of the control unit pressed after you turned
your CYPRES on. CYPRES will continue with its self-test, and once it has finished, it
will propose a DZ air pressure in steps of 1 hPa (1 hPa = 1 mbar).
The display changes in single steps starting with 1, the little arrow pointing upwards.
When the 1 appears on the display the CYPRES asks whether the air pressure at
the intended drop zone is 1 hPa. The display changes to 2 , then to 3 etc. In chapter
4.4.2.1 you will find an example for an altitude adjustment.
