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Power Terminology
Cruise Climb Power
The power recommended to operate the airplane in a cruise
climb (a continuous, gradual climb) profile.
Flight Idle Power
The power required to run an engine, in flight, at the lowest
speed that will ensure satisfactory engine and systems operation
and airplane handling characteristics. Power setting is achieved
with the Power Control Lever at the Flight Idle Detent position.
Ground Idle Power
The power required to run an engine on the ground, as slowly as
possible, yet sufficient to ensure satisfactory engine, engine
accessory, and airplane operation with a minimum of thrust.
Power setting is achieved with the Power Control Lever at or
immediately aft of the Idle Detent position.
Maximum Climb Power
The maximum power approved for climb.
Maximum Cruise Power
The maximum power approved for cruise.
Reverse Thrust
The thrust of the propeller directed opposite the usual direction,
thereby producing a braking action. Power setting is achieved
with the Power Control Lever in the Reverse position.
Takeoff Power
The maximum power permissible for takeoff (limited to 5
minutes).
Zero Thrust
The absence of appreciable thrust, in either direction.
1-5-4
Engine Controls and Instruments Terminology
Beta Range
Range where the propeller blade angle is a function of Power
Control Lever (PCL) input. The Engine Electronic Control (EEC)
utilizes the Np/Beta sensor and beta ring position to calculate
blade angle, which is controlled and commanded by the PCL.
Below flight regime, i.e. aft of the idle detent, the Propeller
Control Unit (PCU) limits the propeller speed to an underspeed
condition and the PCL directly controls the propeller pitch.
Constant Speed Range
The engine operating range where the propeller is out of Beta
range and operating at a constant rpm.
Engine and Propeller
Electronic Control System
(EPECS)
The system that controls the engine’s output torque at a
reference propeller speed by scheduling fuel flow.
ITT Gauge
A temperature measuring system that senses gas temperature
in the turbine section of the engine.
Minimum Blade Angle
When in forward mode, the minimum blade angle is fixed in
order to prevent the propeller from going into reverse. When
reverse is commanded (throttle quadrant input to the EEC) the
minimum blade angle will vary, allowing the propeller to go into
reverse. Minimum blade angle protection is achieved by
momentarily commanding the feather solenoid.
Power Control Lever
The lever used to control engine power, from reverse (see Beta
Range) to maximum power (see Power Terminology).
Propeller Control Unit
(PCU)
The PCU is an electro-hydro-mechanical device that modulates
the blade angle of a single acting propeller over the entire flight
regime of the engine.
Section 1 - General
Power Terminology
Pilot's Operating Handbook
Report No: 02406
Issue date: Mar 06, 2020
Page 1-5-3
12-C-A15-00-0105-00A-005A-A
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