Aircraft plumbing is that phase of aircraft maintenance dealing with
the metal tubing, flexible hoses, and necessary fittings and seals
providing a pathway for the fluids and gases to move between the
components on aircraft.
Although this text deals mainly with the hydraulic system, the
requirements for the fuel, ventilation, pneumatic, and Pitot-static
systems as well.
Because of this similarity, the maintenance
personnel responsible for hydraulic plumbing are usually required to
perform the repair and maintenance of all aircraft plumbing systems.
For the mechanic to repair aircraft plumbing, or for the NCO or
maintenance officer to supervise this work effectively, he must be
familiar with the material, equipment, and fabrication techniques
necessary to repair and install these lines.
Part A of this lesson deals with the identification and methods of
fabricating the tubes that connect the components of hydraulic
In Part B, the uses and advantages of hose or flexible
tubing are explained, including the markings, fabrication and
installation methods, and storage requirements of these materials.
Part C describes the different types of seals and gaskets used to
prevent leaks in the interconnecting tubes, hoses, and fittings of
VARIETY OF LINES
Throughout this lesson you will see terms such as plumbing lines,
tubing, flexible tubing, and hose used extensively.
plumbing lines refer to any duct work used to transfer fluids or
gases from one location to another. These lines may fall into one of
two general categories: tubes (rigid lines), and hose (flexible
Many materials are used to fabricate these lines; each one
offers a different advantage. When replacing a damaged or defective
line, make every effort to duplicate the original line as closely as
Under some circumstances, however, field expediency
requires replacement of the damaged line with a similar, but not
In choosing what size and type of line to use,
evaluate the following important elements:
Type of fluid or gas the line is to conduct.
Pressure it must operate under.
Temperatures it must operate under.