FUEL SYSTEM MAINTENANCE
INTRODUCTION
Maintain, service, and adjust aircraft fuel systems
and fuel system components in accordance with the applicable manufacturer's
maintenance instructions. Certain general fuel system maintenance principles
are outlined in the following paragraphs.
When fuel system lines are to be replaced or
repaired, consider the following fundamentals in addition to the applicable
airworthiness requirements.
a. Compatibility of Fittings.
All fittings are to be compatible with their mating parts. Although various
types of fittings appear to be interchangeable in many cases they have different
thread pitch or minor design differences which prevent proper mating and may
cause the joint to leak or fail.
b. Routing. Make sure
that the line does not chafe against control cables, airframe structure, etc.,
or come in contact with electrical wiring or conduit. Where physical separation of the fuel lines from electrical
wiring or conduit is impracticable, locate the fuel line below the wiring and
clamp it securely to the airframe structure. In no case should wiring be
supported by the fuel line.
c.
Alignment. Locate bends accurately so that
the tubing is aligned with all support clamps and end fittings and is not drawn, pulled, or otherwise forced into
place by them. Never install a straight length of tubing between two
rigidly-mounted fittings. Always incorporate at least one bend between such fittings
to absorb strain caused by vibration and temperature changes.
d. Bonding. Bond
metallic fuel lines at each point where they are clamped to the structure.
Integrally bonded and cushioned line support clamps are preferred to other
clamping and bonding methods.
e. Support of Line Units.
To prevent possible failure, all fittings heavy enough to cause the line to sag
should be supported by means other than the tubing.
f. Support clamps.
(1) Place
support clamps or brackets for metallic lines as follows.
(2) Locate clamps or brackets as close to bends as
possible to reduce 
No comments:
Post a Comment