cates that the igniters are energized. The autoigni-
tion system is triggered from a ready condition to an
operating condition when engine torque drops below
approximately 20%. Therefore, when an autoignition
system is armed, the igniters will be energized con-
tinuously during the time when an engine is operat-
ing at a level below approximately 20% torque. The
autoignition lights are protected by 5-ampere IGNI-
TOR CONTR No. 1 or No. 2 circuit breakers, located
on the overhead circuit breaker panel (fig. 2-26).
b. Engine Torquemeters. Two torquemeters
on the instrument panel indicate torque applied to
the propeller shafts of the respective engines (fig.
2-29). Each gage shows torque in percent of maxi-
mum using 2 percent graduations and is actuated by
an electrical signal from a pressure sensing system
located in the respective propeller reduction gear
case. Torquemeters are protected by individual 0.5-
circuit breakers placarded TORQUE
METER No. 1 or No. 2 on the overhead circuit
breaker panel (fig. 2-26).
2-31. ENGINE STARTER-GENERATORS.
One starter-generator is mounted on each engine
accessory drive section. Each is able to function
either as a starter or as a generator. In the starter
function, 28 volts DC is required to power rotation.
In the generator function, each unit is capable of
400 amperes DC output. When the starting function
is selected, the starter control circuit receives power
through the respective 5-ampere START CONTR
circuit breaker on the overhead circuit breaker panel
from either the aircraft battery or an external power
source. When the generating function is selected, the
starter-generator provides electrical power. For addi-
tional description of the starter-generator system,
refer to Section IX.
c. Turbine Tachometers. Two tachometers on
the instrument panel register compressor turbine
RPM (N1) for the respective engine (fig. 2-29).
These indicators register turbine RPM as a percent-
age of maximum gas generator RPM. Each instru-
ment is slaved to a tachometer generator attached to
the respective engine.
2-32. ENGINE INSTRUMENTS.
The engine instruments are vertically mounted
near the center of the instrument panel (fig. 2-29).
d. Oil Pressure/Oil Temperature Indicators.
Two gages on the instrument panel register oil pres-
sure in PSI and oil temperature in °C (fig. 2-29). Oil
pressure is taken from the delivery side of the main
oil pressure pump. Oil temperature is transmitted by
a thermal sensor unit which senses the temperature
of the oil as it leaves the delivery side of the oil pres-
sure pump. Each gage is connected to pressure trans-
mitters installed on the respective engine. Both
instruments are protected by 5-ampere circuit break-
ers, placarded OIL PRESS and OIL TEMP No. 1 or
No. 2, on the overhead circuit breaker panel (fig.
Turbine Gas Temperature Indicators. Two
TGT gages on the instrument panel are calibrated in
degrees Celsius (fig. 2-29). Each gage is connected to
thermocouple probes located in the hot gases
between the turbine wheels. The gages register the
temperature present between the compressor turbine
and power turbine for the corresponding engine.
e. Fuel Flow Indicators. Two gages on the
instrument panel (fig. 2-29) register the rate of flow
for consumed fuel as measured by sensing units cou-
pled into the fuel supply lines of the respective
engines. The fuel flow indicators are calibrated in
increments of hundreds of pounds per hour. Both
circuits are protected by 0.5-ampere circuit breakers
placarded FUEL FLOW No. 1 or No. 2, on the over-
head circuit breaker panel (fig. 2-26).
2-33. FUEL SUPPLY SYSTEM.
The engine fuel supply system (fig. 2-13) consists
of two identical systems sharing a common fuel
management panel (fig. 2-14) and fuel crossfeed
plumbing (fig. 2-15). Each fuel system consists of
five interconnected wing tanks, a nacelle tank, and
an auxiliary inboard fuel tank. A fuel transfer pump
is located within each auxiliary tank. Additionally,
the system has an engine-driven boost pump, a
standby fuel pump located within each nacelle tank,
a fuel heater (engine oil-to-fuel heat exchanger unit),
a tank vent system, a tank vent heating system and
interconnecting wiring and plumbing. Refer to Sec-
tion IX for fuel grades and specifications. Fuel tank
capacity is shown in table 2-2. Gravity feed fuel flow
is shown in figure 2-16.