SECTION 7
CESSNA
AIRPLANE & SYSTEMS DESCRIPTIONS
MODEL 172RG
has been repositioned, it directs hydraulic pressure within the system to
actuate the gear to the selected position.
LANDING GEAR POSITION INDICATOR LIGHTS
Two position indicator lights, adjacent to the landing gear control
lever, indicate that the gear is either up or down and locked. Both the gear-
up (amber) and gear-down (green) lights are the press-to-test type,
incorporating dimming shutters for night operation. If an indicator light
bulb should burn out, it can be replaced in flight with the bulb from the
remaining indicator light.
LANDING GEAR OPERATION
To retract or extend the landing gear, pull out on the gear lever and
move it to the desired position. After the lever is positioned, the power pack
will create pressure in the system and actuate the landing gear to the
selected position. During a normal cycle, the gear retracts fully or extends
and locks, limit switches close (GEAR DOWN cycle only), and the
indicator light comes on (amber for up and green for down) indicating
completion of the cycle. After indicator light illumination, during a GEAR
DOWN cycle, the power pack will continue to run until the fluid pressure 1
reaches 1500 PSI, opens the pressure switch, and turns the power pack off.
Whenever fluid pressure in the system drops below 1000 PSI, the pressure
switch will close and start power pack operation, except when the nose
gear safety (squat) switch is open.
The safety (squat) switch, actuated by the nose gear, electrically
prevents inadvertent retraction whenever the nose gear strut is com-
pressed by the weight of the airplane. When the nose gear is lifted off the
runway during takeoff, the squat switch will close, which may cause the
power pack to operate for 1 to 2 seconds and return system pressure to 1500
PSI in the event pressure has dropped below 1000 PSI. A "pull-off" type
circuit breaker is also provided in the system as a maintenance safety
feature. With the circuit breaker pulled out, landing gear operation by the
gear pump motor is prevented. After maintenance is completed, and prior
to flight, the circuit breaker should be pushed back in.
EMERGENCY HAND PUMP
A hand-operated hydraulic pump, located between the front seats,
provided for manual extension of the landing gear in the event of
hydraulic system failure. The landing gear cannot be retracted with the
hand pump. To utilize the pump, extend the handle forward, and pump
vertically. For complete emergency procedures, refer to Section 3.
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1 July 1979
CESSNA
SECTION 7
MODEL 172RG
AIRPLANE & SYSTEMS DESCRIPTIONS
LANDING GEAR WARNING SYSTEM
The airplane is equipped with a landing gear warning system designed
to help prevent the pilot from inadvertently making a wheels-up landing.
The system consists of a throttle actuated switch which is electrically
_connected to a dual warning unit. The warning unit is connected to the
airplane speaker.
When the throttle is retarded below approximately 12 inches of
manifold pressure at low altitude (master switch on), the throttle linkage
will actuate a switch which is electrically connected to the gear warning
portion of a dual warning unit. If the landing gear is retracted (or not down
and locked), an intermittent tone will be heard on the airplane speaker. An
interconnect switch in the wing flap system also sounds the horn when the
wing flaps are extended beyond 20° with the landing gear retracted.
BAGGAGE COMPARTMENT
The baggage compartment consists of the area from the back of the
rear passenger seats to the aft cabin bulkhead. A baggage shelf, above the
wheel well, extends aft from the aft cabin bulkhead. Access to the baggage
compartment and the shelf is gained through a lockable baggage door on
the left side of the airplane, or from within the airplane cabin. A baggage
net with six tie-down straps is provided for securing baggage, and is
attached by tying the straps to tie-down rings provided in the airplane. For
further information on baggage tie-down, refer to Section 6 . When loading
the airplane, children should not be placed or permitted in the baggage
compartment, and any material that may be hazardous to the airplane or
occupants should not be placed anywhere in the airplane. For baggage
area and door dimensions, refer to Section 6.
SEATS
The seating arrangement consists of two individually adjustable four-
way or six-way seats for the pilot and front seat passenger, and a split-
backed fixed seat for the rear seat passengers.
The four-way seats may be moved forward or aft, and the seat back
angle adjusted to any comfortable angle. To position either seat, lift the
tubular handle under the center of the seat, slide the seat into position,
release the handle, and check that the seat is locked in place. The seat back
angle is controlled by a cylinder lock release button which is spring-
loaded to the locked position. The release button is located on the right side,
1 July 1979
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