ALT-1 Operating Manual
Page 8
Select if you want to show the built in VSI (vertical speed indicator). The built in VSI will be shown
above the altitude readout.
Select if you want your VSI readout in feet/minute (ft/m) or meters/second (m/s).
Note:
meters/second will be shown with two decimals, example: “1.23”.
This is a function that is used to calibrate your VSI to read exact rates of climb or decent. This
function works as a percentage of initial reading. The default setting for this function is 100%.
Increasing this value increases the VSI reading and decreasing the value decreases the reading.
Suggested VSI calibration method
After you have installed the instrument, perform a calibration flight. This should be done in very calm conditions.
Turbulence and thermal activity will make accurate calibration impossible. Many areas have ideal conditions during early
mornings or late afternoons. Place the instrument in “feet” unit mode for ease of calibration. Take your aircraft to a few
thousand feet above ground and start a glide with a low power setting. Take a stopwatch and when the glide is stable
(stable VSI reading) start the stopwatch. Take note of your altimeter reading at the same time. Continue the stable glide
for one minute exactly. After the minute has finished, take another reading of your altimeter.
Example:
VSI reading during stable glide: -400 ft/min
Start altitude: 2500 ft.
End altitude: 2050 ft.
In the above example the VSI is under reading by about 12%. Set your VSI calibration to 112% to cancel out the error.
4.6 ADC Values
Note:
This menu item is for technical personnel only, and is not displayed during the normal
operation of the instrument. Please see section 4 above on how to access this menu item.
This menu displays the ADC values that have been read from the pressure sensors.
4.7 Calibrate
Note:
This menu item is for technical personnel only, and is not displayed during the normal
operation of the instrument. Please see section 4 above on how to access this menu item. Consult
your local dealer or factory before entering this menu.
Move the highlight over the “DONE” menu item and press the rotary button to return to the main
menu.
