Beechcraft C-12C Operator And Technical Reference Manual page 29

e. Landing Gear Warning Horn. When either
power lever is retarded below approximate 79% N
when the landing gear is not down and locked; or if the
flaps are extended beyond 40%, a warning horn,
located in the overhead control panel, will sound
intermittently. To prevent the horn from sounding
during long descents or an ILS approach, a pressure
differential "Q" switch is connected into the copilot's
static line. This switch prevents the warning horn from
sounding until airspeed drops below 140 KIAS. The
warning horn circuit is protected by a 5-ampere circuit
breaker, placarded LANDING GEAR WARN, on the
overhead circuit breaker panel.
f. Landing Gear Warning Horn Test Switch.
The landing gear warning horn may be tested by a test
switch on the right subpanel. The switch, placarded
STALL WARN TEST / OFF / LDG GEAR WARN
TEST, will sound the landing gear warning horn and
illuminate the landing position warning lights when
moved to the momentary LDG GEAR WARN TEST
position. The circuit is protected by a 5-ampere circuit
breaker, placarded LANDING GEAR WARN, on the
overhead breaker panel.
g. Landing Gear Safety Switches. A switch on
each main landing gear shock strut controls the
operation of various aircraft systems that function only
during flight or during ground operation.
switches are mechanically actuated whenever the
main landing gear shock struts are extended (normally
after takeoff) or compressed (normally after landing).
The safety switch on the right main landing gear strut
deactivates the landing gear control circuits, cabin
pressurization circuits, and the flight hour meter when
the strut is compressed. This switch also deactivates
a down-lock hook, preventing the landing gear from
being raised while the aircraft is on the ground. The
hook, which unlocks automatically after takeoff, can be
manually overridden by pressing the red button,
placarded DN LOCK REL, located adjacent to the
landing gear handle. If the override is used and the
landing gear control switch is raised, power will be
supplied to the warning horn circuit and the horn will
sound. The safety switch on the left main landing gear
strut activates the left and right engine ambient air
shut-off valves when the strut is extended.
h. Alternate Landing Gear Extension Handle.
Continued pumping of handle after GEAR
DOWN position
illuminated could
mechanism and
retractions.
CAUTION
indicator lights
damage the drive
prevent subsequent
Manual landing gear extension is provided
, or through a manually powered system as a backup to
1
the electrically operated system.
extending the gear, make certain that the landing gear
switch handle is in the down position with the
LANDING GEAR RELAY circuit breaker pulled.
Pulling up on the alternate engage handle located on
the floor, and turning it clockwise will lock it in that
position. When the alternate engage handle is pulled,
the motor is electrically disconnected from the system
and the alternate drive system is locked to the gearbox
and motor. When the alternate drive is locked in, the
chain is driven by a continuous actuation ratchet,
which is activated by pumping the alternate landing
gear extension handle adjacent to the alternate
engage handle. Refer to Figure 2-7.
After a manual landing gear extension has
been made, do not stow the handle, move
any landing gear controls, or reset any
switches or circuit breakers.
cannot be retracted manually.
After a practice manual extension, the alternate
handle may be stowed and the landing gear retracted
electrically.
counterclockwise and push it down. Stow the handle,
These
push in the LANDING GEAR RELAY circuit breaker
on the overhead circuit breaker panel, and retract the
gear in the normal manner with the landing gear
handle switch. Refer to Chapter 9 for emergency gear
extension procedures.
i. Landing Gear Alternate Engage Handle.
During manual landing gear extension, the landing
gear motor must be electrically disconnected from the
system and the alternate drive system locked to the
gearbox and motor.
manually operated alternate engage handle located
adjacent to the landing gear alternate extension
handle. Pulling up on the alternate engage handle and
turning it clockwise will lock the manual landing gear
extension system in the engage position.
disengage the system, turn the alternate engage
handle counterclockwise as far as it will go and
release.
are
TM 1-1510-218-10
Before manually
CAUTION
Rotate the alternate engage handle
This is accomplished by a
The gear
To
2-13