(f)  
GAIN - PRE-SET

(g)  
STAB - OFF

(h)  
TILT - 0 Degrees

(i)  
INT - Mid scale

(j)  
RANGE - TEST. Check STBY appears in mode field (Fig. 501).

C.  Test weather radar
(1)  
After a 1 minute warmup, depress WX mode selector. Check test pattern (Fig. 501) appears as follows:

(a)  
TEST displayed in mode field

(b)  
Color bar displayed in auxiliary field

(c)  
Range marks clear and unbroken

(d)  
Range marks are labeled 20, 40, 60, 80, and 100

(e)  
First 3 color bands are green, yellow and red

(f)  
Fourth color band (65 to 80 nm) is yellow

(g)  
Target alert sector is red

(h)  
Noise band between 86 and 95 nm is solid green and extends unbroken across the full display.

(2)  
Rotate INT control in both directions. Check intensity level of test pattern changes.

(3)  
Press AZIM switch/indicator. Check azimuth marks are displayed at 30 degree intervals.

(4)  
Press AZIM switch/indicator. Check azimuth marks are no longer displayed.

(5)  
Press SEC SCAN switch/indicator. Check displayed scan reduces to an 80 degree sector with a scan rate of approximately one sweep each two seconds.

(6)  
Press SEC SCAN switch/indicator. Check scan returns to 160 degrees sector with a scan rate of approximately one sweep each four seconds.

(7)  
Observe scan line sweeping through display. When scan line is at either edge of display, press TGT ALRT switch/indicator. Check target alert field (Fig. 501) displays red box with letter T inside.

(8)  
When scan line enters target alert area, check T is replaced by a flashing TGT ↑ label.

(9)  
Press TGT ALRT switch/indicator. Check target alert field is no longer displayed.

(10)
Press FRZ switch/indicator. Check scan line becomes stationary.

(11)
Press FRZ switch/indicator. Check scan line immediately moves to synchronize with antenna and continue to scan in normal manner.

(12)
Depress CYC mode selector. Check red areas in display flash on and off approximately once each second.

(13)
Depress MAP mode selector. Check test pattern colors green and red change to magenta and cyan.

(14)
If no further test is required, perform Weather Radar Shut-down procedure.

5B8 
34-41-0 Page 502  BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  Feb 20/85 

5D8  Weather Radar Test Modes 
Jun 20/84  Figure 501 BOEING PROPRIETARY - Copyright . - Unpublished Work - See title page for details.  34-41-0 Page 503 

3.  System Test Weather Radar
A.  For the tests involving the display of radar video (echoes from terrain, rainfall, etc.) the airplane should be pointed so antenna sector scan includes hills or mountains preferably at various heights in the distance.
B.  Equipment and Materials
(1)  Portable tilt table with horizontal leveling capabilities and provisions for varying pitch and roll axis of the table platform + 20 degrees. Platform must be capable of mounting a removed vertical gyro (VG) for antenna stabilization accuracy response checks. Accuracy must be 0.25 degrees, or better (used for stabilization accuracy tests).
C.  Referenced procedures
(1)  
24-22-00, Manual Control - Maintenance Practices (apply power).

(2)  
34-22-11, Vertical Gyro - Removal/Installation.

(3)  
34-41-00, Weather Radar System - Adjustment/Test (operational test).

D.  Prepare to test
(1)  
Provide electrical power (Ref 24-22-00, Maintenance Practices).

(2)  
Check WEATHER RADAR AC and DC circuit breakers on electronic circuit breaker panel (P18-1) are closed.

(3)  
Remove selected VG from airplane (Ref 34-22-11, Vertical Gyro R/I) and install on tilt table on a test cart or sturdy table near or under the airplane, or in the airplane if it is fairly stable. Zero level the tilt table platform on all axes.

(4)  
Connect the test extension cable between the VG on the tilt table and the VG connectors on airplane. Energize airplane attitude reference system and check valid attitude signals are being generated by VG.

(5)  
Position controls and switches on weather radar indicator as follows:

(a)  
STBY -Depressed.

Allow one minute warmup period.

(b)  
AZIM switch/indicator - Off

(c)  
SEC SCAN switch/indicator - Off

(d)  
FRZ switch/indicator - Off
　
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