Engine Flashcards
What type of engine powers the aircraft?
1600 SHP Pratt and Whitney PT6A-68B free turbine engine
This engine is designed for high performance and efficiency.
What is unique about the airflow in the engine?
It is a reverse flow engine
The air inlet is at the rear and the exhaust section is at the front.
What type of propeller does the engine drive?
Hartzell constant speed, variable pitch propeller with five graphite composite blades
The propeller rotates clockwise when viewed from the cockpit.
What system automatically manages engine power according to airspeed?
Electronic power management system (PMS)
This system ensures optimal performance during different flight conditions.
What power restriction does the PMS impose during take-off?
Restricts available engine power for take-off
Full power is available above 200 KIAS for sustained high cruise speeds.
Does the engine have a fire extinguisher?
No fire extinguisher
The engine has a fire warning system but lacks an extinguisher.
What are the main components of the gas generator section?
Compressor section, compressor turbine, combustion chamber
The compressor section includes 4 stages of axial compression and 1 stage of centrifugal/radial compression.
What drives the accessory gearbox at the rear of the engine?
Gas generator section
The fixed shaft connects the gas generator to the accessory gearbox.
List the items driven by the accessory gearbox.
- Hydraulic pump
- No. 1 generator (engine starter motor)
- No. 2 generator
- Low pressure fuel pump
- High pressure fuel pump and fuel metering unit (FMU)
- One triple element, triple inlet, main oil pressure pump
- Two double element, gear type, oil scavenge pumps
These components are vital for engine operation and functionality.
How does the gas generator section contribute to the power turbine?
It uses generated gas flow to drive the power turbine section
This process is essential for converting gas energy into mechanical energy.
How many stages does the power turbine have?
Two-stage power turbine
This design allows for effective power conversion to drive the propeller.
What is the function of the reduction gearbox?
Mechanically drives the propeller
It connects the power turbine to the propeller for efficient operation.
In what directions do the compressor turbine and power turbine rotate?
They rotate in opposite directions
This configuration minimizes gyroscopic effects during flight.
How is air supplied to the engine?
Air is supplied to the engine through a chin intake in the front lower cowling.
What system is incorporated in the intake for icing conditions?
The intake system incorporates an inertial separation system operated by the INTAKE switch on the de-ice panel.
What happens to air after it enters the compressor?
Air leaves the compressor and is turned through 90° by diffuser tubes, converting velocity to static pressure.
What occurs in the combustion chamber?
High pressure air is turned through 180°, mixed with fuel, and ignited.
What directs gas to the single-stage compressor turbine?
Turbine inlet guide vanes direct the gas to the single-stage compressor turbine.
What happens after the gas drives the compressor turbine?
The gas continues forward to the two-stage power turbine and exhausts to atmosphere through two exhaust ports.
What is a design feature of the engine related to gas flow?
Reversing the direction of the gas flow produces a compact engine layout.
What controls the engine and propeller in response to pilot inputs?
The PMS controls the engine and propeller through the power control lever (PCL).
How is engine power controlled?
Engine power is controlled by gas generator speed (NG) set by the position of the PCL.
What does the propeller interface unit (PIU) do?
The PIU holds NP constant and torque becomes the measure of power level.
What happens when NP increases to the governing speed?
The PIU holds the NP constant by varying the propeller pitch.
What is the range of movement for the power control lever (PCL)?
The PCL has a range of movement of approximately 90°.
What are the approximate PCL angles for engine operation?
FUEL OFF: -5°, IDLE: 30°, MAX: 80°.
What happens in the FUEL OFF position?
The PCL cuts off the engine fuel supply mechanically and activates the propeller feathering system electrically.
What does the friction control knob do?
The friction control knob increases the force needed to move the PCL when rotated clockwise.
What is the purpose of the de-icing strips on propeller blades?
The de-icing strips prevent the build-up of ice on the surface of the blades.
How do the de-icing strips work?
An electrically operated heater element melts the ice on the surface of the blade, and centrifugal force removes the melted ice.
What protects the leading edge surfaces of each propeller blade?
An erosion strip protects the leading edge surfaces from the effects of erosion.
What does the erosion strip provide in case of a lightning strike?
The erosion strip gives an earth path for the lightning.
What is the function of the engine oil system?
The engine oil system provides a constant supply of clean oil to the engine bearings, reduction gears, accessory drives, and the PIU.
How is oil supplied to the engine?
Oil is supplied from the oil tank by a three element pressure pump and is scavenged by two double element pumps.
What does the oil system lubricate and cool?
The oil lubricates and cools the bearings, lubricates the gears and drives, and provides oil for propeller speed control.
How is the oil cooled?
The oil is cooled by the airframe mounted oil cooler.
Does the oil system require input from the pilot?
No, the oil system operates fully automatically with no input required from the pilot.
What should be avoided to maintain oil pressure?
Manoeuvres causing the oil pressure to go outside the approved limits should be avoided.
Where is the oil tank located?
The oil tank is an integral part of the accessory gearbox assembly.
How is the oil level checked?
Oil contents are indicated by a sight glass on the left side of the compressor inlet case.
What do the magnetic chip detectors do?
They attract ferrous contamination in the oil system.
What happens if sufficient contamination is detected?
An amber CHIP indication on the DWP comes on.
How is oil cooled in the system?
Oil is air-cooled by passing through an oil cooler in a duct under the engine bay.
What regulates the temperature of the oil?
A thermal actuator automatically regulates the temperature of the oil.
What happens to the external flap assembly when the NLG is extended?
The external flap is opened to allow increased airflow through the oil cooler at low speeds and on the ground.
What is the purpose of the ignition system?
The ignition system is used to ignite the fuel/air mixture in the combustion chamber during engine start or rapid engine deceleration to reduce the risk of inadvertent flameout.
How does the igniter exciter unit function?
A sealed igniter exciter unit transforms the 28V DC input to a pulsed high voltage output.
What do the ignition cable assemblies do?
Two individual ignition cable assemblies carry electrical energy from the ignition exciter unit to the engine-mounted spark igniters.
What is the normal position of the ignition switch?
The normal switch position is AUTO.
What happens when the ignition switch is in the IGN position?
In the forward (IGN) position, the igniters are manually selected to ON.
What occurs in the OFF position of the ignition switch?
If either front or rear cockpit switch is held to the rear (OFF) position, the igniters are inhibited.
What does the AUTO position of the ignition switch do?
In the central (AUTO) position, the igniters function automatically, controlled by the PMU.
What indicates that the igniters are operating?
A green IGN caption illuminates on both the DWP and the MFD ENG page whenever the igniters are operating.
What functions are combined in the starter motor unit?
The functions of the starter motor and generator No. 1 (GEN 1) are combined in one unit.
How can the starter motor be energized manually?
The starter motor can be energized manually by selecting the STARTER switch to MAN.
What happens when the STARTER switch is set to AUTO?
When set to AUTO, the PMU automatically controls the starter motor and the auto start sequence starts when the AUTO START push-button is pressed.
What appears on the MFD when the starter is activated?
Whenever the starter is activated, the MFD ENG page appears automatically on the right MFD.
