JDC Electronic SA Geos 11 - Manual (Page 17)

Calibration of QFE pressure
17
In aeronautics, the QFE pressure corresponds to the pressure on the
landing runway (ground level), and is used as the basis for calculating
the height above ground level. Air traffic control will give you this
pressure value.
Select the lower block and display the measuring mode in
relation to the QFE height (it flashes), then keep pushing
the
button down. starts flashing on the upper block.
Release the button as soon as you enter the calibration
function (screen opposite). Use the
button to select
which way the setting is made ( increment,
decrement), then set the value of the pressure using the button.
Pressing briefly on the button sets the value in increments of 0.1 unit.
Keep the
button pressed down in order to enter the settings in one unit
increments. Release then press the button again for a faster setting.
Repeat a second time the “release/keep down” operation to obtain
increments of 10 units. Confirm and exit the calibration by keeping the
button down. The instrument goes back to the standard screen.
Remark: The instrument will display the QFE value (QFE abbreviation
displayed) instead of the absolute pressure, and this as long as the
instrument remains switched on. If turned off and back on again, the
instrument will display the absolute pressure again, but the height will
still remain based on this QFE setting (which can be accessed via
).
DO NOT MODIFY THE CALIBRATION OF THE SENSOR WHICH IS
ACCESSIBLE VIA THE MEASURING MODE FOR ABSOLUTE
PRESSURE, please refer to Section ‘Other’; ‘Calibration of the
Pressure Sensor’.
Compass
Display
The impeller should not be rotating to ensure an accurate reading. This is
due to the fact that the impeller communicates the speed via a small
magnet fitted on its axis. When it rotates, the impeller generates a
magnetic field that interferes with the compass. It is therefore
recommended when using the compass, to rotate the sphere containing
the impeller so as to stop the wind from making it turn.