Flytec Balloon 4:Altitude adjustment
The different altimeters
The Flytec Balloon 4's altimeter indicates altitude above mean sea level (MSL) or Flight Level. In flight mode, the altitude indicator is located at the top right of the display.
- Alt1: MSL altitude in meter (metric setup) or feet (imperial setup)
- Alt2: MSL altitude in feet (metric setup) or meter (imperial setup)
- FL: Flight level, based on QNE (1013 hPa / 29.91 inHg)
Setting QNH or launch altitude
Atmospheric pressure changes over time. Therefore, to get accurate MSL altitude information, the reference pressure or altitude must be set before every flight, and may need to be adjusted during a flight if required by air traffic control. The Flytec Balloon 4 does that automatically for you, but you can override this automatic adjustment manually.
When you turn on your Flytec Balloon 4, as soon as GPS reception has been established, the vario determines its current GPS altitude, and uses this to automatically set QNH. In most cases, this will be sufficiently accurate. The altitude indicator blinks while this process is ongoing. Once launch has been detected, the last measured GPS altitude is used for the flight (unless changed manually) and the altitude indicator stops blinking.
In general, a long press on brings you to the QNH and altitude adjustment screen. Once in adjustment mode, you can use F2 () to toggle between pressure and altitude setting. There are four scenarios for using this screen:
- You know the current barometric pressure calculated for sea level (QNH), as for instance given by an aviation weather report, or by air traffic control.
- You know your present altitude, as for instance determined from a map, or an airfield marking, and that altitude differs from the altitude determined by GPS.
- You want ALT1 and ALT2 to indicate QNE altitude, based on standard atmosphere with 1013 hPa / 29.91 inHg.
- You want to cancel any previous adjustment and return to the automatic adjustment based on GPS altitude.