Types of tube fittings.
Methods of tube flaring and installation.
Techniques of tube repair if tubes are not extensively damaged.
In Army aviation three types of metal tubing are used: aluminum
alloy, stainless steel, and copper. Generally, determine the type of
metal visually. If this is not possible, mark the tubing at three-
foot intervals with the manufacturer's name or trademark, the tubing
material, and its specification number. Tubing that is too small to
be marked in this manner, identify by attaching a tag with this
information to it.
Aluminum. In aircraft plumbing, the most widely used metal tubing
is made of aluminum alloy.
This general-purpose tubing has the
advantages of workability, resistance to corrosion, and light weight.
A list of the aluminum tubing authorized for use in Army aircraft is
found in TM 1-1500-204-23-2.
The aluminum tubing generally used in Army aircraft hydraulic
systems operating at pressures of 1,500 psi and below is type 5052,
Military Specification WW-T-700/4.
Because of the workability of
this tubing, assemblies can be readily fabricated in the field. For
those hydraulic systems operating at pressures above 1,500 psi,
Specification T-7081, are used.
To process this tubing into tubing
assemblies requires special procedures and equipment not generally
available in the field.
Therefore, assemblies made from this
aluminum must be obtained through supply channels as factory
prefabricated parts or through depot maintenance shops.
Stainless Steel. Tubing of stainless steel can also be used where
pressures exceed 1,500 psi. Stainless steel must be used for outside
lines, such as brake lines attached to landing gear struts or other
exposed lines that can be damaged by flying objects or ground-
Stainless steel tubing, like the high-pressure
aluminum alloy tubing, is difficult to form without special tools and
is obtained through supply channels or depot repair facilities.
Copper. Copper tubing is primarily used in high-pressure oxygen
systems. The fittings on copper tubing are soldered on with silver.
Copper tubing used for high-pressure oxygen systems is 3/16-inch
diameter, 0.032-inch wall thickness,