(f)
Set each indicator range switch on indicator below initial setting. Radar returns should move toward top of indicators.
(g)
AF 121, 122, Set each indicator range switch to 30.
(h)
SN 351-399, Set each indicator range switch to 40.
(i)
SN 351-399, On each indicator place the SCAN/HOLD switch to HOLD. 1) Weather returns are frozen 2) Antenna continues to scan. 3) WX mode message changes to an alternating WX-HOLD message.
(j)
SN 351-399, On each indicator place the SCAN/HOLD switch to SCAN. 1) Weather returns are updated with each scan of the antenna. 2) The mode message return to WX.
(k)
Adjust each indicator BRT control. Weather radar returns become brighter as BRT control is rotated clockwise and dimmer as BRT control is rotated counterclockwise.
(l)
On control panel, place SYS switch to 2 and repeat test for system 2.
(m)
If no further tests of weather radar are required, perform Weather Radar System Shutdown Procedure.
(4) Gain Test
NOTE: In the absence of weather, mountains, or prominent buildings
____ more than 300 feet away, visual testing of the gain control except the calibration and gain messages may not be possible.
(a)
Place control panel mode selector to MAP. Check MAP message displays in upper left of indicators.
(b)
On control panel select desired range and adjust TILT control to obtain optimum targets.
(c)
Rotate control panel GAIN control just out of AUTO. Check blue CAL message is displayed, on right side, directly below tilt message. A blue MIN gain message should also be present before the CAL message.
(d)
Adjust control panel GAIN control clockwise toward MAX position. Check for the following: 1) Radar returns on indicators become more prominent. 2) Gain messages change from MIN, 1 thru 9 to MAX.
EFFECTIVITY
AF 121, 122; CONFIG 3 SN 351-399 02 A Page 510 Sep 25/94
34-43-00
(e)
Adjust control panel GAIN control counterclockwise toward AUTO position and check for the following: 1) Weather returns on indicators diminish in intensity. 2) Gain messages change from MAX, 9 thru 1 to MIN.
(f)
On SN 352-399, 1) Place control panel mode selector switch to TURB. 2) Place the indicator range switch to 40. 3) Repeat gain test steps (c), (d) and (e) in the TURB mode.
NOTE: If turbulent storm cells are not present within the
____ antenna scanning direction turbulent returns will not be present on the indicators.
(g)
Return control panel GAIN control to AUTO. Check blue CAL and gain messages are no longer displayed.
(h)
On control panel, place SYS switch to 2 and repeat test for system 2.
(i)
If no further tests of weather radar are required, perform Weather Radar System Shutdown Procedure.
(5) Antenna Tilt Test
(a)
Place control panel mode selector to WX or MAP. Check indicator displays appropriate messages for range mode, range mark interval, and tilt.
(b)
Adjust control panel tilt control in steps from 0 to plus 15.0(x) degrees, then back to 0 degree. Tilt message on both indicators should read tilt angle | 1 degree.
NOTE: (X) -- an arrow, pointing upwards or downwards
____ corresponding to plus or minus tilt setting selected, will be displayed.
(c)
Rotate control panel tilt control in steps from 0 to minus 15.0(x) degrees then back to 0 degree. Tilt message on both indicators should read tilt angle | 1 degree.
(d)
Rotate control panel tilt control to -4 degrees. Check close-in targets are more prominent.
(e)
Adjust control panel TILT control to obtain optimum targets.
(f)
On control panel, place SYS switch to 2 and repeat test for system 2.
(g)
If no further tests of weather radar are required, perform Weather Radar System Shutdown Procedure.
(6) Stabilization Test (Using Tilt Table)
(a) Place INS mode select switch in OFF position and shut down INS (Ref 34-41-00 INS A/T).
EFFECTIVITY
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本文链接地址：747飞机维护手册AMM CHAPTER 34 - NAVIGATION 第34章导航3(139)
