CHAPTER 14
BRAKE SYSTEMS
INTRODUCTION
the brake assembly in the wheel. This action results in
the friction necessary to stop the wheel.
Three types of brake systems are currently in use
When the brake pedal is released, the master
on naval aircraft. They are the independent-type brake
cylinder piston is returned to the OFF position by a
system, the power boost brake system, and the power
return spring. Fluid that was moved into the brake
brake control valve system. In addition, there are
assembly is then pushed back to the master cylinder by
several different types of brake assemblies currently in
a piston in the brake assembly. The brake assembly
use.
piston is returned to the OFF position by a return spring
in the brake.
TYPES OF BRAKE SYSTEMS
The typical master cylinder has a compensating
port or valve that permits fluid to flow from the brake
LEARNING OBJECTIVES: Identify the
chamber back to the reservoir when excessive pressure
three major brake systems. Recognize the
is developed in the brake line due to temperature
operation of the emergency brake system.
changes. This feature ensures against dragging or
locked brakes.
The three major types of brake systems are the
Various manufacturers have designed master
independent, power boost, and power brake control
cylinders for use on aircraft. All are similar in
valve system.
operation, differing only in minor details and
construction. Two types of master cylinders, the
INDEPENDENT-TYPE BRAKE SYSTEM
Goodyear and the Gladden, are described here.
In general, the independent-type brake system is
Goodyear Master Cylinder
used on small aircraft. This type of brake system is
termed independent because it has its own reservoir
A cutaway view of the Goodyear master cylinder is
and is entirely independent of the aircraft's main
shown in figure 14-2. Fluid is fed by gravity to the
hydraulic system.
master cylinder from an external reservoir. The fluid
The independent-type brake system is powered by
enters through the cylinder inlet port and
m a s t e r cy l i n d e r s s i m i l a r t o t h o s e u s e d i n t h e
compensating port and fills the master cylinder casting
conventional automobile brake system. However,
ahead of the piston and the fluid line leading to the
there is one major difference--the aircraft brake
brake actuating cylinder.
system has two master cylinders while the automobile
system has only one.
Application of the brake pedal, which is linked to
the master cylinder piston rod, causes the piston rod to
An installation diagram of a typical
push the piston forward inside the master cylinder
independent-type brake system is shown in figure
casting. A slight forward movement blocks the
14-1. The system is composed of a reservoir, two
compensating port, and the buildup of pressure begins.
master cylinders, and mechanical linkage, which
This pressure is transmitted to the brake assembly.
connects each master cylinder with its corresponding
brake pedal, connecting fluid lines, and a brake
When the brake pedal is released and returns to the
assembly in each main landing gear wheel.
OFF position, the piston return spring pushes the front
piston seal and the piston back to full OFF position
Each master cylinder is actuated by toe pressure on
against the piston return stop. This action again clears
its related pedal. The master cylinder builds up
the compensating port. Fluid that was moved into the
pressure by the movement of a piston inside a sealed
brake assembly and brake connecting line is then
fluid-filled cylinder. The resulting hydraulic pressure
is transmitted to the fluid line, which is connected to
pushed back to the master cylinder by the brake piston
14-1
