PC-21 Engine Systems Flashcards
What is the name of the PC-21 engine?
Pratt and Whitney PT6A-68B free turbine engine.
What are some details about the propeller?
Hartzell, five bladed, variable pitch, constant speed propeller that rotates clockwise when viewed from the cockpit.
What does the PMS do?
Automatically controls the power necessary for high speed cruise flight, while retaining docile handling characteristics at low speeds and at the stall.
What does the PMS automatically restrict available engine power to on TO?
1080 SHP
When does the PMS allow full engine power?
Above speeds of 200 KIAS
What is maximum engine power in ISA conditions?
1600 SHP
What are the two sections in the PC-21 engine?
Gas generator and power turbine section
What does the gas generator section comprise of? What else does it drive and where is this located?
- Compressor section
- Combustion Chamber
- Compressor turbine
- Drives the Accessory Gearbox at the rear of the engine.
How is the power turbine section driven and what does it in turn drive?
By the gas flow from gas generator section.
Drives the reduction gearbox.
What are the main components of the PMS?
- Power Management Unit (PMU)
- Permanent Magnet Alternator (PMA)
- Fuel Metering Unit (FMU)
- Propeller Interface Unit (PIU)
- Data Collection Unit (DCU)
- Power Control Lever (PCL)
What part of the PMS provides all the functions required for fuel control and propeller governing?
PMU
What is the primary power source for the PMU? What occurs if the electrical system fails?
- PMA
- PMA still powers the PMU in the event of a failure of the electrical power supply system.
What type of unit is the FMU and what does it control?
- Electro-hydraulic-mechanical
- Controls fuel flow
What type of unit is the PIU and what does it control?
- Electro-hydraulic-mechanical
- Controls pitch angle of the propeller
What does the DCU do?
Stores engine information for maintenance use.
What items are installed on and driven by the AGB?
1) Fuel Metering Unit (FMU)
2) Main oil pump
3) AGB chip detector
4) 2 Oil Scavenge pumps
5) Low and high pressure fuel pumps
6) Hydraulic pump
7) GEN 1 and 2
8) Oil Tank
What does the ignition system consist of?
- Airframe mounted ignition exciter unit
- Ignition cables
- Two spark igniters
What does the engine oil system consist of?
- Pressure system
- Scavenge system
- Breather system
Where is the oil tank integrated and what allows for a visual check of the oil level?
- Integrated into the AGB
- Sight glass marked MAX HOT and MAX MIN.
How is the oil cooled?
By an airframe mounted oil cooler
Where are the two fire overheat detectors installed?
1) No. 1 is around the hot section of the gas generator case
2) No. 2 is around the accessory gearbox.
What cockpit engine controls does the PC-21 have?
1) Power Control Leve (PCL) including the idle-detent release.
2) INTAKE switch on De-Ice panel
3) ENGINE panel
Which displays are engine related information shown?
1) EMD
2) MFDs
3) DWP
Why do the compressor turbine and power turbine sections rotate in opposite directions?
To minimize gyroscopic effects.
What does the inertial separator system do and how is it activated?
- Protects the engine from ice, heavy rain and FOD. - When activated, a bypass door opens and through the venturi effect, heavier than air particles are thrown out the bypass door.
- Activated by the INTAKE switch on the de-ice panel.
When inertial separator switch operates, how much is max engine power reduced by?
21 ft lb torque.
What is the primary measure of engine power level at all times except very low engine power ?
Torque.
What is the PCL position sensed by?
Transformer that sends a signal to the PMU.
What is the Bowden cable for?
In the event of PMU failure, the Bowden cable mechanically links the PCL to the FMU.
How does the PMS regulate engine power output and propeller speed?
- Adjusts fuel flow to control engine output power
- Adjusts propeller speed by controlling propeller blade angle.
What controls engine start automatically on the ground and in the air?
The PMS.
What occurs during PMS auto start?
All engine parameters are monitored and automatically maintained within limits.
What has to occur for the PMS to enter manual mode?
- If the PMS detects a critical fault
- If either pilots operates the PMS pushbutton on the ENGINE panel.
When are ground and flight idle the same? What is this value.
- When PMS is in manual mode.
- 67% +- 7% NG
What limits should be adhered to in manual mode?
Only with maximum engine power scheduled according to the PMS power schedule.
What does the engine oil system consist of and what does it do?
- Pressure systems
- Scavenge systems
- Breather systems
- Provides constant supply of clean oil to engine bearing, reduction gears, accessory drives and the PIU.
Where is the oil contents sight glass located?
Left side of the compressor inlet case.
What should be done within 30 mins of engine shutdown but ideally within 15 to 20 mins?
Oil level should be checked.
What system is used to detect metal contamination in the oil and what alert will be trigged and where?
- AGB chip
- “CHIP AGB” warning will appear on the DWP and MFD.
When is the ignition system activated?
- During engine start
2. During rapid engine deceleration to prevent inadvertent flameout.
How does the pilot control the ignition switch?
Using the IGN switch on the ENGINE panel.