brake disc. Since the brakes are self-adjusting,
A pressure switch associated with each solenoid
they always maintain the proper clearance.
control valve provides an electrical signal when
Both brake assemblies are controlled by a
the brake is engaged. A low-pressure alarm switch
is also provided in the turbine brake panel to
panel (fig. 8-19). The solenoid valve is controlled
provide an electrical signal whenever the input air
electrically at the PCC, the LOP, or the SCC. The
pressure drops below 70 psi. Normal operating
valve may be actuated manually at the propeller
pressure is between 70 to 125 psi. An air receiver
shaft brake panel. A pressure switch associated
at the inlet to the turbine brake panel maintains
with the solenoid valve provides an electrical
a constant volume for brake engagement.
signal when the brakes are engaged. A low-
pressure alarm switch is also provided in the
Shaft Brakes
propeller shaft brake panel. The alarm switch
provides an electrical signal whenever the input
A propeller shaft brake assembly (fig. 8-18)
air pressure drops below 1,150 psi. Normal
is mounted on each starboard first-reduction quill
operating pressure is 1,250 psi reduced down from
shaft. Each brake assembly has three disc caliper
3,000 psi. An air receiver at the inlet to the
brakes, The disc caliper brakes are pneumatically
propeller shaft brake panel maintains a constant
operated and are self-retracting. Each brake
volume for brake engagement.
includes two brake pads, one on each side of the
DISC CALIPER
BRAKE
SHAFT BRAKE
HOUSING
AIR HOSE
CALIPER
AIR HOSE
BRAKE
BLOCK
SHAFT OIL
SEAL ASSY
CALIPER
CALIPER
BRACKET
BRAKE
BLOCK
INNER SIDE
PISTON SUBASSY
DISC CALIPER
BRAKE PADS
BRAKE
RETRACTOR
COVER
INPUT AIR
OUTER SIDE
HOSE
PISTON SUBASSY
CALIPER
DISC CALIPER
BRACKET
BRAKE
CALIPER BRAKE
BLOCK
Figure 8-18.--Typical propeller shaft brake assembly.
8-28
