Operation Manual

LX90xx system Version 4.0 February 2014
Page 127 of 151
8.1.3 Set Elevation and QNH
This setting is crucial for final glide calculation: therefore pay careful attention to it.
The instrument will offer elevation from the terrain database based on current latitude and
longitude. Elevation will mostly be within few meters from the current elevation. Use the
PAGE selector knob to fine-tune the elevation. If the elevation is unknown and the QNH
pressure is known you should NOT press button QNH. Just keep turning the PAGE selector
knob and observe the QNH value to adjust it to proper value. The QNH button should be
pressed only when airfield elevation and QNH pressure are given. This might happened on
some competitions. In all other cases elevation should always match QNH pressure.
The profile selection and Elevation dialogues are not shown if the system is
switched off and on during flying.
8.1.4 Preflight Check
After elevation setup the system will switch to airport mode. It will take few moments to
draw the map screen for the first time. All waypoint files and databases are loaded at that
time and therefore instrument might react somewhat slowly.
It is recommended to check the MacCready, ballast and bugs settings to match the current
glider configuration. Press the MC/BAL button. The dialogue for MacCready, Ballast and
bugs will appear.