Terrain Awareness Warning System
In SETUP MENU > TERRAIN LEGEND item. Default is ON > Legend Menu is always displayed on the map:
Once the TAWS has been set, the color scheme is always displayed. It doesn’t matter which scale is being used.
The TAWS rules can be divided into two different sets:
- L1=500ft agl / M1=1000ft agl / H1=2000ft agl
- L2=1000ft agl / M2=2000ft agl / H2=3000ft agl
L1 and L2 take as reference the Land Elevation value (the value of the terrain altitude in respect of the sea level) which allows TAWS rules to calculate the color scheme to be used for depicting the Obstacle Clearance Height (OCH).
This calculation considers the Lowland and Highland definition:
A - Lowland is the terrain under 3000 feet of elevation
B - Highland is the terrain over 3000 feet of elevation
Rules L1/M1/H1 applies to the case (A - Lowlands), while rules L2/M2/H2 applies to the case (B - Highlands).
The OCH, Obstacle Clearance Height, is the result you have from the difference of your own altitude (fix ALT) less the Land Elevation:
OCH = ALT – LE
In Lowland case the TAWS colours will be red, yellow and green accordingly to the following values of the OCH:
- Red: L1= from < 0 ft up to 500 ft
- Yellow: M1= from <= 500 ft up to 1000 ft
- Green: H1= from <= 1000 up to 2000 ft
- Transparent (no color): over 2000 ft
In Highland case the TAWS colours will be red, yellow and green accordingly to the following rules:
- Red: L1= from < 0 ft up to 1000 ft
- Yellow: M1= from <= 1000 ft up to 2000 ft
- Green: H1= from <= 2000 up to 3000 ft
- Transparent (no color): over 3000 ft