Engine

Question 1

What type of engine powers the aircraft?

Answer 1

1600 SHP Pratt and Whitney PT6A-68B free turbine engine

This engine is designed for high performance and efficiency.

Question 2

What is unique about the airflow in the engine?

Answer 2

It is a reverse flow engine

The air inlet is at the rear and the exhaust section is at the front.

Question 3

What type of propeller does the engine drive?

Answer 3

Hartzell constant speed, variable pitch propeller with five graphite composite blades

The propeller rotates clockwise when viewed from the cockpit.

Question 4

What system automatically manages engine power according to airspeed?

Answer 4

Electronic power management system (PMS)

This system ensures optimal performance during different flight conditions.

Question 5

What power restriction does the PMS impose during take-off?

Answer 5

Restricts available engine power for take-off

Full power is available above 200 KIAS for sustained high cruise speeds.

Question 6

Does the engine have a fire extinguisher?

Answer 6

No fire extinguisher

The engine has a fire warning system but lacks an extinguisher.

Question 7

What are the main components of the gas generator section?

Answer 7

Compressor section, compressor turbine, combustion chamber

The compressor section includes 4 stages of axial compression and 1 stage of centrifugal/radial compression.

Question 8

What drives the accessory gearbox at the rear of the engine?

Answer 8

Gas generator section

The fixed shaft connects the gas generator to the accessory gearbox.

Question 9

List the items driven by the accessory gearbox.

Answer 9

• 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.

Question 10

How does the gas generator section contribute to the power turbine?

Answer 10

It uses generated gas flow to drive the power turbine section

This process is essential for converting gas energy into mechanical energy.

Question 11

How many stages does the power turbine have?

Answer 11

Two-stage power turbine

This design allows for effective power conversion to drive the propeller.

Question 12

What is the function of the reduction gearbox?

Answer 12

Mechanically drives the propeller

It connects the power turbine to the propeller for efficient operation.

Question 13

In what directions do the compressor turbine and power turbine rotate?

Answer 13

They rotate in opposite directions

This configuration minimizes gyroscopic effects during flight.

Question 14

How is air supplied to the engine?

Answer 14

Air is supplied to the engine through a chin intake in the front lower cowling.

Question 15

What system is incorporated in the intake for icing conditions?

Answer 15

The intake system incorporates an inertial separation system operated by the INTAKE switch on the de-ice panel.

Question 16

What happens to air after it enters the compressor?

Answer 16

Air leaves the compressor and is turned through 90° by diffuser tubes, converting velocity to static pressure.

Question 17

What occurs in the combustion chamber?

Answer 17

High pressure air is turned through 180°, mixed with fuel, and ignited.

Question 18

What directs gas to the single-stage compressor turbine?

Answer 18

Turbine inlet guide vanes direct the gas to the single-stage compressor turbine.

Question 19

What happens after the gas drives the compressor turbine?

Answer 19

The gas continues forward to the two-stage power turbine and exhausts to atmosphere through two exhaust ports.

Question 20

What is a design feature of the engine related to gas flow?

Answer 20

Reversing the direction of the gas flow produces a compact engine layout.

Question 21

What controls the engine and propeller in response to pilot inputs?

Answer 21

The PMS controls the engine and propeller through the power control lever (PCL).

Question 22

How is engine power controlled?

Answer 22

Engine power is controlled by gas generator speed (NG) set by the position of the PCL.

Question 23

What does the propeller interface unit (PIU) do?

Answer 23

The PIU holds NP constant and torque becomes the measure of power level.

Question 24

What happens when NP increases to the governing speed?

Answer 24

The PIU holds the NP constant by varying the propeller pitch.

Question 25

What is the range of movement for the power control lever (PCL)?

Answer 25

The PCL has a range of movement of approximately 90°.

Question 26

What are the approximate PCL angles for engine operation?

Answer 26

FUEL OFF: -5°, IDLE: 30°, MAX: 80°.

Question 27

What happens in the FUEL OFF position?

Answer 27

The PCL cuts off the engine fuel supply mechanically and activates the propeller feathering system electrically.

Question 28

What does the friction control knob do?

Answer 28

The friction control knob increases the force needed to move the PCL when rotated clockwise.

Question 29

What is the purpose of the de-icing strips on propeller blades?

Answer 29

The de-icing strips prevent the build-up of ice on the surface of the blades.

Question 30

How do the de-icing strips work?

Answer 30

An electrically operated heater element melts the ice on the surface of the blade, and centrifugal force removes the melted ice.

Question 31

What protects the leading edge surfaces of each propeller blade?

Answer 31

An erosion strip protects the leading edge surfaces from the effects of erosion.

Question 32

What does the erosion strip provide in case of a lightning strike?

Answer 32

The erosion strip gives an earth path for the lightning.

Question 33

What is the function of the engine oil system?

Answer 33

The engine oil system provides a constant supply of clean oil to the engine bearings, reduction gears, accessory drives, and the PIU.

Question 34

How is oil supplied to the engine?

Answer 34

Oil is supplied from the oil tank by a three element pressure pump and is scavenged by two double element pumps.

Question 35

What does the oil system lubricate and cool?

Answer 35

The oil lubricates and cools the bearings, lubricates the gears and drives, and provides oil for propeller speed control.

Question 36

How is the oil cooled?

Answer 36

The oil is cooled by the airframe mounted oil cooler.

Question 37

Does the oil system require input from the pilot?

Answer 37

No, the oil system operates fully automatically with no input required from the pilot.

Question 38

What should be avoided to maintain oil pressure?

Answer 38

Manoeuvres causing the oil pressure to go outside the approved limits should be avoided.

Question 39

Where is the oil tank located?

Answer 39

The oil tank is an integral part of the accessory gearbox assembly.

Question 40

How is the oil level checked?

Answer 40

Oil contents are indicated by a sight glass on the left side of the compressor inlet case.

Question 41

What do the magnetic chip detectors do?

Answer 41

They attract ferrous contamination in the oil system.

Question 42

What happens if sufficient contamination is detected?

Answer 42

An amber CHIP indication on the DWP comes on.

Question 43

How is oil cooled in the system?

Answer 43

Oil is air-cooled by passing through an oil cooler in a duct under the engine bay.

Question 44

What regulates the temperature of the oil?

Answer 44

A thermal actuator automatically regulates the temperature of the oil.

Question 45

What happens to the external flap assembly when the NLG is extended?

Answer 45

The external flap is opened to allow increased airflow through the oil cooler at low speeds and on the ground.

Question 46

What is the purpose of the ignition system?

Answer 46

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.

Question 47

How does the igniter exciter unit function?

Answer 47

A sealed igniter exciter unit transforms the 28V DC input to a pulsed high voltage output.

Question 48

What do the ignition cable assemblies do?

Answer 48

Two individual ignition cable assemblies carry electrical energy from the ignition exciter unit to the engine-mounted spark igniters.

Question 49

What is the normal position of the ignition switch?

Answer 49

The normal switch position is AUTO.

Question 50

What happens when the ignition switch is in the IGN position?

Answer 50

In the forward (IGN) position, the igniters are manually selected to ON.

Question 51

What occurs in the OFF position of the ignition switch?

Answer 51

If either front or rear cockpit switch is held to the rear (OFF) position, the igniters are inhibited.

Question 52

What does the AUTO position of the ignition switch do?

Answer 52

In the central (AUTO) position, the igniters function automatically, controlled by the PMU.

Question 53

What indicates that the igniters are operating?

Answer 53

A green IGN caption illuminates on both the DWP and the MFD ENG page whenever the igniters are operating.

Question 54

What functions are combined in the starter motor unit?

Answer 54

The functions of the starter motor and generator No. 1 (GEN 1) are combined in one unit.

Question 55

How can the starter motor be energized manually?

Answer 55

The starter motor can be energized manually by selecting the STARTER switch to MAN.

Question 56

What happens when the STARTER switch is set to AUTO?

Answer 56

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.

Question 57

What appears on the MFD when the starter is activated?

Answer 57

Whenever the starter is activated, the MFD ENG page appears automatically on the right MFD.