contamination to be removed from the fluid before it reaches the various operating components. Filters
of this type are referred to as line filters.
Line Filter Construction. A typical line filter is shown in Figure 1-3. It has two major parts--the
filter case, or bowl, and the filter head. The bowl holds the head that screws into it. The head has an
inlet port, outlet port, and relief valve. Normal fluid flow is through the inlet port, around the outside of
the element, through the element to the inner chamber, and out through the outlet port. The bypass
valve lets the fluid bypass the filter element if it becomes clogged.
Figure 1-3. Typical Line Filter Assembly.
Types of Filter Elements. The most common filtering element used on Army aircraft is the micronic
type. It is a disposable unit made of treated cellulose and is formed into accordion pleats, as shown in
Figure 1-3. Most filter elements are