PRIMUSr 880 Digital Weather Radar System
Radar Mode - Ground Mapping
NOTE: Refer to Tilt Management in Section 5, Radar Facts, for additional information on the use of tilt control.
Ground- mapping operation is selected by setting the controls to GMAP. The TILT control is turned down until a usable amount of navigable terrain is displayed. The degree of down- tilt depends on the aircraft altitude and the selected range.
The receiver STC characteristics are altered to equalize ground- target reflection versus range. As a result, selecting preset GAIN generally creates the desired mapping display. However, the pilot can control the gain manually (by selecting manual gain and rotating the GAIN control) to help achieve an optimum display.
With experience, the pilot can interpret the color display patterns that indicate water regions, coast lines, hilly or mountainous regions, cities, or even large structures. A good learning method is to practice ground- mapping during flights in clear visibility where the radar display can be visually compared with the terrain.
TEST MODE
The PRIMUSâ 880 Digital Weather Radar System has a self- test mode and a maintenance function.
In the self- test (TST) mode a special test pattern is displayed as illustrated earlier in this section. The functions of this pattern are as follows:
DColor Bands - A series of green/yellow/red/magenta/white bands, indicate that the signal to color conversion circuits are operating normally.
The maintenance function lets the pilot or the line maintenance technician determine the major fault areas. The fault data can be displayed in one of two ways (selected at the time of installation):
DTEXT FAULT - A plain English text indicating the failure is placed in the test band.
DFault code - A fault code is displayed, refer to the maintenance manual for an explanation.
The indicator or EFIS display indicates a fault as noted below.
DDedicated Radar Indicator - A FAIL annunciation is shown at the top left corner of the test pattern. It indicates that the built- in test equipment (BITE) circuitry is detecting a malfunction. The exact nature of the malfunction can be seen by selecting TEST. (Refer to Section 7, In- Flight Troubleshooting.)
Normal Operation | A28- 1146- 102- 00 |
|
