(d)
Do not repair dents or chafed areas. Replace the tube or tube section if the defect depth is more than the values in Fig.
803. It is not necessary for you to repair or replace tubes
with defect depth less than these values.Electrical rigid conduit repair.
(a) Smooth dents are permitted to the electrical rigid conduit with these limits as shown in Fig. 842. 1) Dent depth damage is not more than 20 percent of the outer diameter. 2) The conduit is not dented or has a scratch that causes it to have kinks, to rub, or to show the inner wire. 3) The dent is smooth and does not make a sharp wrinkle on the outer surface of the conduit. 4) There are no cracks in the conduit. 5) Dents are no permitted on rigid electrical conduits in the
fuel tanks.
(b)
Repair or replace electrical rigid conduits if the damage is more than the limits.
(c)
If you must form the rigid conduit tube to fit an installation, do not bend more than permitted by the forming limits for electrical rigid conduits as shown in Fig. 843.
To repair a damaged tube section, cut out the damaged tube section
and replace it with a fitting or with an assembled tube and fitting
assembly.
To replace a BACA14BP fitting you must use another BACA14BP fitting.
Install the new BACA14BP or D10203 fitting on the new tube section
(AMM 20-11-05/801).
NOTE: Use BACA14BP fittings only for replacement of other BACA14BP
____ fittings unless approved by The Boeing Company on a case-by-case basis. The MS screw-together ends on this fitting are prone to deformation and galling from repeated assembly and disassembly and may leak.
(a) Do an electrical resistance check where required (AMM 20-11-05/401).
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
20-11-05
ALL ú ú 04 Page 807 ú Feb 18/02
BOEING PROPRIETARY - Copyright (C) - Unpublished Work - See title page for details.
A
747-400
MAINTENANCE MANUAL
(8)
To replace a BACU24AB swage union, cut out the damaged fitting and replace it with a B-nut, BACS13AP sleeve or BACS13BX sleeve or a CRYOLIVE flareless sleeve assembly and an MS21924 bulkhead union, using the procedures of Fig. 807.
(9)
To make tube repairs, use tube sections of the same material and use the fittings as shown in Fig. 802. You can make splice a repair of 21-6-9 and Ti-3AL-2.5V tube with 304-1/8h tube of the wall thickness shown in Fig. 821 or 824.
(10)
The permitted limits of hydraulic line damage caused by dents, chafes, or the corrosion removal process per the Corrosion Prevention Manual, are shown in Fig. 803.
(11)
A repair of a tube section can be in one of three groups. The groups have a relation to the location of the tube damage and the quantity of damage. The three groups are as follows:
(a)
Replace a tube end section that has a flareless end fitting you can move apart, with an assembled tube and fitting assembly (Fig. 806).
(b)
Replace a tube center section that has a short damaged segment with a single union (Fig. 805).
(c)
Replace a tube center section that has very much damage with an assembled tube and fitting assembly (Fig. 809).
(12)
If you disconnected more than one hydraulic tube and you think there is a possibility you connected the tubes incorrectly or cross-connected the tubes, do an operational check:
NOTE: Use your own judgement to determine if a check is necessary.
____
(a) Do the post-installation test of one of more components to which the tubes are connected as a check.
(13) If you disconnected electrical wires to get access to the tubes and you think there is a possibility you connected the wires incorrectly or cross-connected the wires, do an operational check:
NOTE: Use your own judgement to determine if a check is necessary.
____
(a) Do the post-installation test of one of more components to which the wires are connected as a check.
B. Repair of a Tube (Make a Splice)
S 948-287
(1)
Make a decision about the type of repair necessary. Use Fig. 802 to make a decision about the group the repair is in.
S 948-288
(2)
Refer to Fig. 805 to find the necessary tube cutout length when you use a single union to replace a damaged tube area.
EFFECTIVITYùùùùùùùùùùùùùùùùùùùùùùùùùùùùùù. ú
中国航空网 www.aero.cn
航空翻译 www.aviation.cn
本文链接地址：747-400 AMM 飞机维护手册 STANDARD PRACTICES - AIRFRAME(21)
