TM 55-1510-215-10
illuminate red, when this test button is pressed, indicates
will sound. The safety switch on the left main landing
two defective bulbs or a circuit fault. The circuit is
gear strut activates the engine inlet air separator, the
protected by a 5-ampere circuit breaker, placarded LDG
nacelle lip ice boots and heater ram air intake boot when
the strut is extended, and the two ventilation air blowers
(for nose avionics and cockpit/cabin areas) when the
e. Landing Gear Warning Horn.
When either
strut is compressed.
power lever is retarded below approximately 80% N1
when the landing gear is not down and locked, a warning
CAUTION
horn behind the left side of the instrument panel will
sound intermittently.
The warning horn circuit is
protected by a 5-ampere circuit breaker, placarded LG
Do not pump handle after GEAR
DOWN position indicator lights (3)
are illuminated. Further movement of
f. Landing Gear Warning Horn Silence Button.
the handle could damage the drive
The landing gear warning horn can be silenced during
mechanism.
flight (with power retarded, gear and flaps up), by
pressing the button, placarded WARN HORN SILENCE,
h. Landing Gear Emergency Clutch Disengage
Lever. Prior to emergency or manual landing gear
warning horn, it will remain silent until either the flaps are
extension, the landing gear motor must be disengaged
extended or the power levers are advanced, then
from the landing gear drive mechanism.
This is
retarded again. During single-engine operation, the
accomplished by a manually operated clutch disengage
warning horn may be silenced by either pressing the
lever (fig. 2-6) located adjacent to the landing gear
warning horn silence button (flaps up) or advancing the
emergency extension handle. To disengage the clutch,
power lever for the inoperative engine to a position
pull the clutch lever up and turn clockwise. To engage
above the warning horn microswitch setting. If the
the clutch, turn the clutch lever counter-clockwise and
warning horn has been silenced by pressing the silence
release.
button, the power lever for the inoperative engine must
again be advanced past the warning horn microswitch
i. Landing Gear Emergency Extension Handle.
setting to reset the switch. The horn will sound however,
The landing gear emergency extension handle (fig. 2-6)
if the power lever for the operative engine is retarded.
located on the cockpit floor to the right of the pilot's seat,
The circuit is protected by a 5-ampere circuit breaker,
is used for manual extension of the landing gear. The
placarded LG WARN HORN, on the right subpanel
landing gear extension system is actuated by pumping
the handle up and down. This movement operates a
ratchet mechanism which drives the normal system to
g. Landing Gear Safety Switches . A safety switch
extend the landing gear. The landing gear cannot be
on each main landing gear shock strut controls the
retracted manually. Refer to chapter 9 for emergency
operation of various aircraft systems that function only
gear extension procedures.
during flight or only during ground operation. These
switches are mechanically actuated whenever the main
2-7. Steerable Nose Wheel.
landing gear shock struts are extended (normally after
takeoff), or compressed (normally after landing). The
The aircraft can be maneuvered on the ground by
safety switch on the right main landing gear strut
the steerable nose wheel system. Direct linkage from
deactivates the landing gear control circuits when the
the rudder pedals to the nose wheel steering linkage
strut is compressed. This switch also activates a down-
allows the nose wheel to be turned 12 to the left of
center or 14 to the right. When rudder pedal steering is
lock hook, preventing the landing gear handle from being
raised while the aircraft is on the ground. The hook,
augmented by the main wheel braking action, the nose
which unlocks automatically after takeoff, can be
wheel can be deflected up to 48 either side of center.
manually over-ridden by pressing down on the red
Shock loads which would normally be transmitted to the
button, placarded DN LCK REL located adjacent to the
rudder pedals are absorbed by a spring mechanism in
landing gear handle (fig. 2-7). If the over-ride is used
the steering linkage. Retraction of the landing gear
and the landing gear control switch is raised, power will
automatically centers the nose wheel and disengages
be supplied to the warning horn circuit and the horn
the steering linkage from the rudder pedals.
2-10