position until both power levers are advanced above 86% N 1 and/or airspeed increases above approximately 153
In either case (airspeeds above or below 140 KIAS); the landing gear warning system will be rearmed if both power
levers are advanced above 86% N 1 . With the laps beyond the APPROACH position, the warning horn and landing
gear switch handle annunciators will be activated regardless of the power setting. The horn cannot be silenced in
this case, until either the landing gear is lowered, or the laps are retracted to the UP or APPROACH position.
f. Landing Gear Warning Horn Test Switch. The warning horn and gear handle annunciators can be tested by
placing the switch placarded STALL WARN TEST OFF LDG GEAR WARN TEST to the LDG GEAR WARN TEST
position (Fig. 2-11). The gear handle annunciators will illuminate, and warning horn will sound. Releasing the LDG
GEAR WARN TEST switch to the OFF position will extinguish the gear handle annunciators and silence the warning
horn. The landing gear warning horn circuit is protected by a 5-ampere circuit breaker placarded LANDING GEAR
HORN located on the overhead circuit breaker panel (Fig. 2-12).
g. Landing Gear Safety Switches. A safety switch on each main landing gear shock strut controls the oper-
ation of various aircraft systems that function only during light or only during ground operation. These 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 light hour meter when the shock strut is compressed.
This switch also activates 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 down on the
red button, placarded DOWN LOCK REL located adjacent to the landing gear handle (Fig. 2-11). If the override
is used, the landing gear warning horn will sound intermittently and two, red, parallel-wired annunciators located in
the landing gear control switch handle will illuminate, provided the battery switch is on. 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.
After an emergency landing gear extension has been made, do not move any landing gear con-
trols, or reset any switches or circuit breakers until the aircraft is on jacks. The failure may have
been in the gear-up circuit which could cause the gear to retract while the aircraft is on the ground.
If for any reason the three green GEAR DOWN indicator lights do not illuminate (i.e., in case of
an electrical system failure), continue pumping until suficient resistance is felt to ensure that the
gear is down and locked. Do not stow the hand pump handle. Stowing the handle will release
hydraulic pressure. If the three GEAR DOWN indicator lights are not illuminated, the landing gear
down locks may not be engaged and hydraulic pressure may be the only thing holding the landing
h. Landing Gear Alternate Extension. An extension lever, placarded LANDING GEAR ALTERNATE EXTEN-
SION , is located on the loor between the crew seats (Fig. 2-19). A manual pumping action with the handle lowers
the landing gears. The hydraulic pump utilized to manually lower the gear is located under the loor. To engage the
system, pull the LANDING GEAR CONTROL circuit breaker, located on the overhead circuit breaker panel (Fig.
2-12), and ensure that the LDG GEAR CONTROL handle is in the DN position. Remove the extension lever from
the securing clip and pump the lever up and down until the three green GEAR DOWN annunciators illuminate. As
the handle is moved hydraulic luid will be drawn from the hand pump suction port of the power pack and routed
through the hand pump pressure port to the actuators. After an alternate extension of the landing gear, ensure the
extension lever is in the full down position prior to stowing the pump handle in the retaining clip. When the pump
handle is stowed, an internal relief valve is actuated to relieve the hydraulic pressure in the pump.
After a practice alternate extension, stow the extension handle, reset the LANDING GEAR CONTROL circuit
breaker, and retract the gear in the normal manner with the landing gear control handle.
i. Tires. The aircraft is equipped with dual 22 x 6.75 x 10, 10 ply rated, tubeless, rim inlation tires on each main
gear and a single 22 x 6.7 5x 10, 10 ply rated, tubeless tire on the nose wheel. The tires are speed rated to 190
MPH, which is approximately 167 Knots.
j. Nose Wheel Steering System. The aircraft is maneuvered on the ground by the steerable nose wheel sys-
tem. Direct linkage from the rudder pedals to the nose wheel steering linkage allows the nose wheel to be turned
12° to the left of center or 14° to the right. When the main wheel braking action augments rudder pedal steering,
the nose wheel can be delected up to 48° either side of center. Shock loads which would normally be transmitted
to the rudder pedals are absorbed by a spring mechanism in the steering linkage. Retraction of the landing gear
automatically centers the nose wheel and disengages the steering linkage from the rudder pedals.