S 214-014
(9)
Do a check of the O-ring on the antenna:
NOTE: On some airplanes, the thru-hole for the connector post
____ on the antenna is wider than the O-ring groove on the antenna. If you see this, do not install the O-ring because it will not operate as a seal.
(a)
Replace the O-ring, if it is necessary.
(b)
Put a layer of BMS 3-24 on the O-ring and in the O-ring groove.
(c)
Install the O-ring in the O-ring groove on the antenna.
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(10) Connect the antenna cable to the antenna post.
(a) Make sure the connector is tight without twist tension from the cable.
S 354-067
(11) Do this procedure to apply a layer of BMS 3-27 on the antenna faying surface on the fairing:
CAUTION: DO NOT PUT BMS 3-27 ON THE O-RING OR IN THE O-RING GROOVE.
_______ IF YOU APPLY BMS 3-27 TO THESE AREAS, THE O-RING WILL NOT SEAL CORRECTLY.
(a) Apply a thin layer of BMS 3-27 to the antenna base and up the antenna post as shown in Fig 401.
S 824-035
(12) Put the antenna in its position on the screw holes on the fairing.
NOTE: Make sure the FWD arrow on the antenna points at the nose
____
of the airplane.
S 434-019
(13) Apply a thick layer of BMS 3-27 to the threads and shank of the cadmium-plated stainless steel screws, then install all except one of the screws to attach the antenna to the fairing.
NOTE: Tighten the screws equally in a diagonal pattern until
____
the antenna is tight against the fairing.
S 434-059
(14) Use the torque wrench to tighten the screws in a diagonal pattern to 20 to 22 inch-pounds.
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WARNING: DO NOT GET SOLVENTS IN YOUR MOUTH, OR YOUR EYES, OR ON YOUR
_______ SKIN. DO NOT BREATHE THE FUMES FROM SOLVENTS. PUT SOLVENTS ARE HAZARDOUS MATERIALS. SOLVENTS MAY BE FLAMMABLE OR HARMFUL TO THE ENVIRONMENT. REFER TO PRODUCT MATERIAL SAFETY DATA SHEETS (MSDS) AND LOCAL REQUIREMENTS FOR PROPER HANDLING PROCEDURES.
(15) Clean the excess BMS 3-27 from around the antenna base with solvent, Series 95 (AMM 20-30-95)
NOTE: Aerodynamic sealant, BMS 5-95 will not bond to BMS 3-27.
____
S 764-021
(16) Use the ohmmeter to do a resistance test between the antenna base and the airplane skin (AMM 20-22-01/601).
NOTE: This is the electrical bond resistance between the antenna
____ base and the metallic flame-spray surface of the fairing.
Remove the paint and primer from a small area on the fairing to provide a contact for the ohmmeter probe.
(a) Make sure the resistance is not more than 0.025 ohms.
S 424-114
(17)
Install the last screw to attach the antenna to the fairing.
S 424-115
(18)
Use the torque wrench to tighten the screw to 20 to 25 inch-pounds.
S 394-051
(19)
Put BMS 5-95 at a 45 degree angle around the edge of the antenna base (AMM 51-31-01/201).
NOTE: Put BMS 5-95 on the heads of the screws in the antenna.
____ Smooth the sealant so that it is not higher than the bottom face of the antenna.
S 414-038
(20) Install the radio altimeter R/T in the center equipment center (AMM 34-33-02/401).
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本文链接地址：747-400 AMM 飞机维护手册 导航 NAVIGATION 2(80)
