NAVIGATION AND
COMMUNICATION
AIRPLANE
OPERATIONS
MANUAL
2-18-45
Page
10
Code
01
REVISION 38
AOM-145/1114
GROUND MAPPING MODE (GMAP)
This mode is used to alert the flight crew regarding hazards caused by
ground targets. This is especially useful in areas of rapidly changing
terrain, such as mountainous regions. In this mode the system is fully
operational and all internal parameters are set to enhance returns from
ground targets.
The TILT control should be turned down until the desired amount of
terrain is displayed. The degree of down-tilt depends upon airplane
altitude and the selected range. Receiver characteristics are altered to
provide equalization of ground-target reflection versus range. The
selection of calibrated GAIN will generally provide the desired mapping
display. If required, variable gain may be used to reduce the level of
strong returns.
In the ground mapping mode a GMAP label is displayed on the PFDs’
and MFDs’ radar mode field, and the color scheme is changed to
cyan, yellow and magenta. Cyan represents the least reflective return,
yellow is a moderate return and magenta represents the most highly
reflective target return.
For airplanes equipped with dual control panels, it is possible to have
one pilot working the GMAP while the other one is using the regular
WX mode.
CAUTION:
WEATHER TYPE TARGETS ARE NOT CALIBRATED
WHEN THE RADAR IS IN THE GMAP MODE.
THEREFORE, THE PILOT SHOULD NOT USE THE
GMAP MODE FOR WEATHER DETECTION.
To Next Page
