Flytec 3040 QNH correction - Manual (Page 2)

The QNH
The QNH is the actual air pressure in hPa (hectopascal) based on sea level.
One hectopascal corresponds to one millibar (mbar). In aviation the QNH serves as the zero
point for the altitude calculation and is announced daily at air fields and in the flight weather
report. Using the QNH you can calibrate your instrument on the day of your flight.
Correcting the QNH
After a year or two, the QNH may begin to show slight deviations due to ageing of the pressure
sensor. In this case you can correct the QNH independently of the altitude.
ATTENTION : If these correction are not made correctly or accurately,
all altimeter and barometer values will be inaccurate.
1. Set the display to ALT ft. By pressing on the key Alti ft for approximately 4 seconds you
can enter the setting mode .
2. Set the exact altitude of your position with the arrow keys UP und DOWN .
3. Compare the displayed QNH with the QNH given in the weather report for the day and
note the difference.
4. Press simultaneously on the keys 1, 2, 3, 4
to get into the QNH Correction-Mode.
5. You are now in the QNH-Correction setting mode. Correct now the difference in
(0,1 mbar) steps, which the QNH 3040 of the balloon equipment deviates from the up-
to-date announced QNH. Press twice the key Alti ft, in order to leave the adjusting mode.
6. In the display ALT ft. the altidude is now beeing actualised. This new height does no longer
correspond with the height from you entered before. Go now again into the altitude adjusting
mode, and enter again the exact height of your position. Now the QNH agrees with the
announced QNH.
7. Once you have made this setting, your pressure value is correct again and it will need
no adjustment for some time.
(Display m blinking)
QNH-Correction-E-All.pdf