The power turbine governor senses the increases and
reduces the flow of fuel to the gas producer, thus de-
creasing the engine output power.
The power turbine speed governor allows the power tur-
bine output speed to decrease (droop) approximately 10
percent when the power loading varies from minimum to
full load. This is minimized by a droop eliminator linked
to the thrust control rod. The droop eliminator automati-
cally changes the power turbine lever to compensate for
droop as pitch is increased or decreased. Another type
of droop, which is only transient, occurs as a result of the
time required for the engine to respond to changing loads
due to system lag.
2-3-8. ENG COND Levers 712
Two ENG COND (engine condition) levers, one for each
engine are on the ENG COND panel (fig. 2-3-1) of the
overhead switch panel. Each lever has three positions
labeled STOP, GND, and FLT. They are used to select
appropriate fuel flow rates for GND, FLT, and STOP (en-
gine shutdown). Power is supplied by the DC essential
buses through the ENGINE NO. 1 and NO. 2 COND
CONT circuit breakers on the No. 1 and No. 2 PDP.
Each ENG COND lever is spring-loaded outboard and is
inhibited by lock gates. They allow the pilot to proportion-
ally control acceleration of the gas producer from STOP
to FLT. Two engine control caution capsules are on the
master caution panel (fig 2-14-5). They are labeled NO.
1 ENG N1 CONT and NO. 2 ENG N1 CONT. The cap-
sules normally illuminate when the ENG COND levers or
the N1 actuators are at an intermediate position between
STOP, GND, or FLT. They extinguish when the ENG
COND lever and N1 actuator positions agree. However,
they remain illuminated if a component of the system
(actuator, control box, or condition panel) has failed in
other than a detent position. Power is supplied by the DC
essential bus through the LIGHTING CAUTION PNL cir-
cuit breaker on the No. 1 PDP.
Figure 2-3-1. Engine Condition Panel 712
When the ENG COND lever is placed to
GND during start sequence, the N1 actua-
tor could inadvertently go beyond the
ground position. The respective ENG N1
COND caution capsule will illuminate.
However, ignition will still occur if the start
switch is moved to START, thus resulting
in a possible engine runaway.
When adjusting controls or switches on
the overhead switch panel, make sure
gloves or sleeves do not catch and inad-
vertently move the ENG COND levers.
The ENG COND lever must be at GND before the engine
will start. When an ENG COND lever is advanced from
STOP to GND, power is then supplied to the electrome-
chanical actuator which establishes an appropriate fuel
flow rate at ground idle. The speed of the gas producer
with the lever at GND should be 60 to 63 percent N1.
When an ENG COND lever is moved to FLT, the engine
is operating within the N2 governing range, unless the
engine is topped out at which time it goes back to N1
governing. The N2 governor then takes control to main-
tain selected rotor RPM (RRPM) in response to the en-
gine beep trim switches and collective pitch changes,
When an ENG COND lever is moved to STOP, the gas
producer lever closes the fuel control fuel shutoff valve
which stops fuel flow to the gas producer.
Each electrical system is completely separate and a fail-
ure in one system will not affect the other. A built-in me-
chanical brake holds the actuator at its last selected posi-
tion if loss of electrical power occurs. ENG COND lever
friction is provided to reduce the possibility of overtorqu-
ing the engine transmissions by resisting movement of
the ENG COND levers. The ENG COND lever friction
brake cannot be adjusted by the pilot and a force of 4 to
5 pounds is needed to move them.
2-3-9. Normal Engine Beep Trim Switches.
712 On 712 engine installations engine beep trim
switches are active at all times during normal operation.
Two momentary switches are on the auxiliary switch
bracket of each THRUST CONT lever and are labeled
ENGINE BEEP TRIM (fig. 2-5-1). Both switches have an
RPM INCREASE, RPM DECREASE, and a neutral posi-
tion. 712 One switch is labled NO. 1 & 2 which is normal-
ly used to select desired RRPM. The second switch is
labeled NO. 1 which will only affect the No. 1 engine and
is used to match engine loads which are indicated by the