Brauniger AV Pilot II, Руководство по эксплуатации

Страница: 19 / 50

When the weather changes fast (e.g. cold fronts), air pressure can change in the course of a
day by up to 5 mbar. This represents a change in altitude of 40 meters!
Another method of calibrating an altimeter is by entering the current QNH. What is the QNH?
In flying circles, a general zero point is needed to enable all aircraft at the same altitude to also
have the same altitude on their altimeters. This joint basis is called the QNH. The QNH is the
current air pressure in hPa (1 hPa = 1 mbar) calculated at sea-level. It is redetermined several
times daily and can be obtained in the flying weather report or from airfields by radio.
Altimeter 1 (ALT 1)
Altimeter 1 displays absolute altitude, i.e. the altitude above sea-level.
Function key is used to change from the displays for altimeter 1, altimeter 2 and the stop-
watch. Pressing and holding down this key will make the instrument go into setting mode.
Altimeter 1 setting mode
As mentioned above, the absolute altitude can be
set in setting mode. The altitude and the QNH flash
on 2 lines. Using the setting keys
and , you can set the altitude and the QNH
simultaneously. If you do not know what altitude
you are currently at, you can set the altitude using
the QNH but this method is not as precise as direct
altitude setting. The QNH has a resolution of 1
mbar which corresponds to an altitude resolution
of approximately 8 meters. The altitude, however,
can be set directly to an accuracy of 1 meter.
Pressing the setting keys and simulta-
neously will take you from setting mode to option
mode.
Altimeter 1 option mode
In option mode, you can set the unit for ALT 1
(meters or feet) at the first level and, at the second
level, you can set the unit for the QNH (hPa or in
Hg). The indicator for the relevant unit set flashes
in the display.
The pressure sensor can be corrected at the third
level (± 50 hPa).
If you find that the QNH value displayed at a known altitude deviates seriously from the QNH
value of a weather station in your area, you can correct this deviation by entering the deviati-
on (with a different prefix). I.e. if the QNH displayed by your instrument is 20 hPa too high, enter
-20 to correct this deviation.
This deviation is caused by the aging of the pressure sensor and stabilizes after 2 - 3 years.
ALT 1
ALT 2
CHRONO
SET-MODE
ALT 1/QNH
OPTION-MODE
ALT1 Unit
m - ft
QNH Unit
hPa - inHg
Sensor
Correction
ALT 1
ALT1
ALT1 4 Sec.
OPTION
OPTION
À
Á
Â
17 Operating Instructions AV Pilot II
START - STOP
RESET
CLEAR ALT 2
CLEAR ALT 2
START - STOP
RESET