spring moves the piston rapidly back to the top of the
Q14-7. What is the purpose of the brake debooster
cylinder?
debooster. This rapid movement causes a suction in the
line to the brake assembly, resulting in faster release of
Q14-8. With the exception of those aircraft equipped
the brake.
with independent-type brake systems, what
additional brake systems are provided?
EMERGENCY BRAKE SYSTEM
BRAKE ASSEMBLIES
On all aircraft except those equipped with
independent-type brake systems, an emergency brake
LEARNING OBJECTIVE: Identify the
system is provided. On some aircraft a pneumatically
various types of brake assemblies.
operated emergency system is provided. Others have a
reserve hydraulic system; an emergency hydraulic
Brake assemblies commonly used on naval aircraft
reservoir retains a sufficient supply of hydraulic fluid
are the single disc, dual disc, multiple or trimetallic
for manual operation of the brakes in case no hydraulic
disc, and segmented rotor. The single and dual disc
power is available.
types are more commonly used on small aircraft; the
multiple or trimetallic disc types are normally used on
The power boost brake system, described earlier, is
medium-sized aircraft; and the segmented rotor types
equipped with a pneumatically operated emergency
are commonly found on heavier types of aircraft.
system. The emergency system consists of a T-handle,
compressed air bottle, air release valve, and pressure
SINGLE DISC BRAKES
gauge.
The system is operated by pulling the T-handle.
The single disc brake is very effective for use on
This releases the compressed air stored in the air bottle.
smaller types of aircraft. Braking is accomplished by
Air pressure unseats the shuttle valves at the air inlet
applying friction to both sides of a rotating disc--the
ports and seats the hydraulic pressure ports. Air
disc being keyed to the landing gear wheel. There are
pressure is then applied directly to the brakes.
several variations of the single disc brake; however, all
operate on the same principle and differ mainly in the
Once air pressure has been applied, the brake can
number of cylinders and the types of brake housing.
be released only by depressing a button on the air
Brake housings may be either the one piece or divided
release valve. Brake systems must be bled after using
type. Figure 14-9 shows a single disc brake installed
the emergency pneumatic systems, and the air storage
on an aircraft, with the wheel removed. The brake
bottle must be serviced with the specified amount of
housing is attached to the landing gear axle flange with
dry compressed air or nitrogen. A pressure gauge
mounting bolts.
indicates the amount of air in the bottle, in pounds per
square inch (psi).
Figure 14-10 shows an exploded view of a typical
single disc brake assembly. This brake assembly has a
Q14-1. What type of brake assembly has its own
three-cylinder, one-piece housing. Each cylinder in
reservoir and is entirely independent of the
aircraft's main hydraulic system?
Q14-2. On a Goodyear master brake cylinder, how is
the hydraulic fluid fed from the external
reservoir to the master cylinder?
Q14-3. What method is used to bleed a brake system
employing a Goodyear master cylinder?
Q14-4. The main system pressure in a power boost
brake system is used for what function?
Q14-5. Because of the weight and size, what type of
brake system is used on aircraft requiring a
large volume of fluid to operate the brakes?
Q14-6. What connects the brake pedal linkage to the
control valve of the power brake control valve
Figure 14-9.--Typical single disc brake installation.
(pressure ball type)?
14-8
