Textron Cessna 172S Skyhawk SP, Information Manual

Page: 190 / 491

CESSNA
MODEl: 172S
BRAKE SYSTEM
SECTION 7
AIRPLANE & SYSTEMSDESCRIPTION
The airplane has a single-disc, hydraulically actuated brake on
each. main landing gear wheel. Each brake is connected, by a
hydraulic line, to a master cylinder attached to each of the pilot's
rudder pedals. The brakes are operated by applying pressure to the
top of either the left (pilot's) or right (copilot's) set of rudder pedals,
which are interconnected.
When the airplane is. parked, both main
wheel brakes may be set by utilizing the parking brake which is
operated by a handle under the left side of the. instrument panel. To
apply the parking brake, set the brakes with the rudder pedals, pull
the handle aft, and rotate it 90° down .
•
For maximum brake life, . keep the brake system properly
maintained, and minimize brake usage during taxi operations and
landings. .. . .
Some of the symptoms of impending brake failure are: gradual
. decrease in braking action after brake application, noisy or dragging
brakes, soft or spongy pedals, and excessive travel. and weak
braking action. If any of these symptoms .appear, the. brake system
.is in need of immediate attention. If, durin.g. taxi or landing roll,
braking action decreases, let up on the pedals and then reapply the
brakes with heavy pressure. If the brakes become spongy or pedal
travel increases, pumping the pedals should build braking pressure.
If one brake becomes weak or fails, use the other brake sparingly
while using opposite rudder, as required, to offset the good brake.
ELECTRICAL SYSTEM
The airplane is equipped with a 28-volt, direct. current electrical.
system (Refer to Figure 7-7). The system is powered by a bell-
driven, 50-amp alternator and a 24-volt battery, .located on the left
forward
side of the firewall. Power is supplied to most general
electrical circuits through a split primary bus bar,. with an essential
bus wired
between the two primaries to provide power for the
master switch, annunciator circuits .and interior lighting. •
Each primary bus. bar is also connected to an avionics bus bar
via a single avionics master switch. The primary buses are on
anytime the master switch is turned on, and are not affected by
starter or external power usage. The avionics buses are on when
the
master switch and avionics master switch are in the ON
position.
May
30/00 7-29