CAUTION: THE PISTON POSITION SPRING CARTRIDGE IS SPRING LOADED TO EXTENDED POSITION. THEREFORE, UPPER TORSION LINK SHOULD BE HELD WHILE APEX BOLT IS BEING REMOVED).
(b)
Adjust sliding scale on fixture so that its 0 position is located on -100 or -200 mark (to agree with airplane type body). Lock scale in position.
(c)
Position fixture under electronics compartment hatchway with vee end pointing forward.
(d)
Raise fixture and rest vee end of arm assembly against aft side of the nose gear shock strut and at the other end, the support bracket angle on the airplane structure flange at Sta 324 (Fig. 201). Adjust support bracket assy to engage support bracket assembly pin into keeper fitting of access door lock at Sta 324.
(e)
Raise hanger bracket and attach to door stop assembly at Sta 294.
(f)
Level assembly by adjusting hanger bracket.
(g)
Install scope on scope mounts.
(h)
Attach target cable assy to the up-lock rollers on the main gear struts with cable attachments. When in position, cable should be taut and ball situated to left of airplane centerline (Fig. 201 and 202).
(i)
Ensure that locknuts on support bracket assembly are loose, to permit movement of fixture from side to side using vee block as a pivot point.
(j)
Sight through telescope and adjust fixture at aft bracket in azimuth until ball is centered in telescope sight. Tighten locknuts in aft bracket to ensure that crosshair and 0 mark on scale will remain at a fixed angle to centerline of airplane.
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502 Target Fixture and Transit Arrangement
May 15/67 Figure 202 34-21-0
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(2)
Fit ground downlocks to landing gear and tow airplane around compass rose at least once, then position airplane on compass rose to meet following conditions:
(a)
Airplane heading within 2 degrees of magnetic north
(b)
Heading roughly tangential to a circle drawn about transit base
(c)
Compass swinging fixture readily seen from transit base (Fig. 202).
(3)
Provide external electrical power to airplane.
(4)
Energize both compass systems by closing circuit breakers listed in Compass Systems -Adjustment/Test. Set compass transfer switches, if fitted, to normal configuration for the systems.
(5)
Set up transit on baseplate in center of compass rose and calibrate as follows:
(a)
Level off transit and sight on marker No.1. Unlock transit lower motion and set scale to read magnetic bearing. of marker minus 66 degrees for 737-200 airplanes and 67 degrees, 58 minutes for 737-100 airplanes. Lock lower motion.
NOTE: If bearing thus calculated results in a minus quantity; add 360 degrees to it in order to validate it.
(b)
Check transit calibration with marker No. 2. Transit should read marker's magnetic heading minus 66 degrees for 731-200 airplanes and 67 degrees 58 minutes for 737-100 airplanes. Correct as necessary.
(c)
Repeat steps (a) and (b) until transit is correctly calibrated.
NOTE: The transit is purposely calibrated to read magnetic heading minus 66 degrees for 737-200 airplanes and 67 degrees 58 minutes for 737-100 airplanes, since it is used to measure airplane heading through the target fixture.
(6)
Place radio power switches to ON. Select a localizer frequency on VHF NAV control panel.
(7)
Set flight director MODE selector to VOR-LOC and weather radar MODE selector to STBY.
(8)
Check that landing gear downlocks are in place. Energize landing gear lever latch by placing a mild steel slug against sensitive surface of air sensing sensor (S106). Do not move landing gear lever while solenoid is energized. The solenoid shall be energized at least 20 minutes before proceeding with test.
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D. Swing Compass
(1)
Deleted.
(2) 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：737 AMM 飞机维护手册 导航 NAVIGATION 1(62)
