Change 3 2-1
AIRCRAFT AND SYSTEMS DESCRIPTION AND OPERATION
The purpose of this chapter is to describe the aircraft,
and its systems and controls which contribute to the
physical act of operating the aircraft. It does not contain
descriptions of avionics or mission equipment covered
elsewhere in this manual. This chapter also contains the
emergency equipment installed. This chapter is not de-
signed to provide instructions on the complete mechani-
cal and electrical workings of the various systems;
therefore, each is described only in enough detail to
make comprehension of that system sufficiently com-
plete to allow for its safe and efficient operation.
The RC-12N is a pressurized, low wing, all metal air-
craft, powered by two PT6A-67 turboprop engines (fig.
2-1), having all weather capability. Distinguishable fea-
tures of the aircraft are the slender, streamlined engine
nacelles, four-bladed propellers, aft rotating boom an-
tenna, mission antennas, wing tip pods, stabilons, T-tail,
and a ventral fin below the empennage. The basic mis-
sion of the aircraft is radio reconnaissance. Cabin en-
trance is made through a stair-type door aft of the wing
on the left side of the fuselage (fig. 2-1). The interior con-
figuration of the aircraft is shown in figure 2-2.
Overall aircraft dimensions are shown in figure 2-3.
GROUND TURNING RADIUS.
Minimum ground turning radius of the aircraft is
shown in figure 2-4.
a. Takeoff. Maximum gross takeoff weight is 16,200
b. Landing. Maximum gross landing weight is 15,400
c. Maximum Ramp Weight. Maximum ramp weight
is 16,320 pounds.
d. Maximum Zero Fuel Weight. Maximum zero fuel
weight is 13,100 pounds.
EXHAUST AND PROPELLER DANGER AREA.
Danger areas to be avoided by personnel while air-
craft engines are being operated on the ground are de-
picted in figure 2-5. Distance to be maintained with
engines operating at idle are also shown. Temperature
and velocity of exhaust gases at varying locations aft of
the exhaust stacks are shown for maximum power. The
danger area extends to 40 feet aft of the exhaust stack
outlets. Propeller danger areas are also shown.
LANDING GEAR SYSTEM.
The retractable tricycle landing gear is electrically
controlled and hydraulically actuated. The landing gear
assemblies are extended and retracted by a hydraulic
power pack, located in the left wing center section, for-
ward of the main spar. The power pack consists primarily
of a hydraulic pump, a 28 VDC motor, a gear selector
valve and solenoid, a two section fluid reservoir, filter
screens, gear-up pressure switch and low fluid level sen-
sor. Engine bleed air, regulated to 18 to 20 PSI, is
plumbed into the power pack reservoir and the system fill
reservoir to prevent cavitation of the pump. The fluid level
sensor activates an amber caution annunciator, plac-
arded HYD FLUID LOW, located on the caution/advisory
annunciator panel, whenever the fluid level in the power
pack is low. The annunciator is tested by pressing the
HYD FLUID SENSOR TEST switch located on pilots
subpanel (fig. 2-6).
Power for the hydraulic power pack is supplied
through the landing gear motor relay and a 60-ampere
circuit breaker located under the floorboard forward of
the main spar. The motor relay is energized by power fur-
nished through the 2-ampere LANDING GEAR CON-
TROL circuit breaker located on the overhead circuit
breaker panel (fig. 2-7). The power pack motor is pro-
tected by a time delay module which senses operation
voltage through a 5-ampere circuit breaker. Both are lo-
cated beneath the aisleway floorboards, forward of the
main spar. Landing gear extension or retraction is nor-
mally accomplished in 6 to 7 seconds. Voltage to the
power pack is terminated after the fully extended or re-
tracted position is reached. If electrical power has not ter-
minated within 14 seconds, a relay and 2-ampere landing
gear circuit breaker will open, and electrical power to the
system power pack will be interrupted.