PC-21 Engine Systems Flashcards
1
Q
What is the name of the PC-21 engine?
A
Pratt and Whitney PT6A-68B free turbine engine.
2
Q
What are some details about the propeller?
A
Hartzell, five bladed, variable pitch, constant speed propeller that rotates clockwise when viewed from the cockpit.
3
Q
What does the PMS do?
A
Automatically controls the power necessary for high speed cruise flight, while retaining docile handling characteristics at low speeds and at the stall.
4
Q
What does the PMS automatically restrict available engine power to on TO?
A
1080 SHP
5
Q
When does the PMS allow full engine power?
A
Above speeds of 200 KIAS
6
Q
What is maximum engine power in ISA conditions?
A
1600 SHP
7
Q
What are the two sections in the PC-21 engine?
A
Gas generator and power turbine section
8
Q
What does the gas generator section comprise of? What else does it drive and where is this located?
A
- Compressor section
- Combustion Chamber
- Compressor turbine
- Drives the Accessory Gearbox at the rear of the engine.
9
Q
How is the power turbine section driven and what does it in turn drive?
A
By the gas flow from gas generator section.
Drives the reduction gearbox.
10
Q
What are the main components of the PMS?
A
- Power Management Unit (PMU)
- Permanent Magnet Alternator (PMA)
- Fuel Metering Unit (FMU)
- Propeller Interface Unit (PIU)
- Data Collection Unit (DCU)
- Power Control Lever (PCL)
11
Q
What part of the PMS provides all the functions required for fuel control and propeller governing?
A
PMU
12
Q
What is the primary power source for the PMU? What occurs if the electrical system fails?
A
- PMA
- PMA still powers the PMU in the event of a failure of the electrical power supply system.
13
Q
What type of unit is the FMU and what does it control?
A
- Electro-hydraulic-mechanical
- Controls fuel flow
14
Q
What type of unit is the PIU and what does it control?
A
- Electro-hydraulic-mechanical
- Controls pitch angle of the propeller
15
Q
What does the DCU do?
A
Stores engine information for maintenance use.
16
Q
What items are installed on and driven by the AGB?
A
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
17
Q
What does the ignition system consist of?
A
- Airframe mounted ignition exciter unit
- Ignition cables
- Two spark igniters
18
Q
What does the engine oil system consist of?
A
- Pressure system
- Scavenge system
- Breather system
19
Q
Where is the oil tank integrated and what allows for a visual check of the oil level?
A
- Integrated into the AGB
- Sight glass marked MAX HOT and MAX MIN.
20
Q
How is the oil cooled?
A
By an airframe mounted oil cooler
21
Q
Where are the two fire overheat detectors installed?
A
1) No. 1 is around the hot section of the gas generator case
2) No. 2 is around the accessory gearbox.
22
Q
What cockpit engine controls does the PC-21 have?
A
1) Power Control Leve (PCL) including the idle-detent release.
2) INTAKE switch on De-Ice panel
3) ENGINE panel
23
Q
Which displays are engine related information shown?
A
1) EMD
2) MFDs
3) DWP
24
Q
Why do the compressor turbine and power turbine sections rotate in opposite directions?
A
To minimize gyroscopic effects.
25
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.
26
When inertial separator switch operates, how much is max engine power reduced by?
21 ft lb torque.
27
What is the primary measure of engine power level at all times except very low engine power ?
Torque.
28
What is the PCL position sensed by?
Transformer that sends a signal to the PMU.
29
What is the Bowden cable for?
In the event of PMU failure, the Bowden cable mechanically links the PCL to the FMU.
30
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.
31
What controls engine start automatically on the ground and in the air?
The PMS.
32
What occurs during PMS auto start?
All engine parameters are monitored and automatically maintained within limits.
33
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.
34
When are ground and flight idle the same? What is this value.
- When PMS is in manual mode.
| - 67% +- 7% NG
35
What limits should be adhered to in manual mode?
Only with maximum engine power scheduled according to the PMS power schedule.
36
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.
37
Where is the oil contents sight glass located?
Left side of the compressor inlet case.
38
What should be done within 30 mins of engine shutdown but ideally within 15 to 20 mins?
Oil level should be checked.
39
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.
40
When is the ignition system activated?
1. During engine start
| 2. During rapid engine deceleration to prevent inadvertent flameout.
41
How does the pilot control the ignition switch?
Using the IGN switch on the ENGINE panel.
42
What are the 2 relevant MFD pages for engine operation?
- MFD ENG
| - MFD SYS
43
What is the EMD and what is shown on it? What is only shown outside of normal limits?
- Engine Monitoring Display
- Engine torque (TQ)
- Oil Temperature (C) - only shown if outside normal limits.
- Oil Pressure
- Propeller speed (NP) - only shown if outside limits
- Gas Generator Speed (NG) - only shown if outside normal limits
- Inter turbine Temperature (ITT)
- Fuel Flow (Lb/Hr)
44
How is the PMU powered during engine start/shutdown or if the PMA fails?
By 28V DC from the BATT BUS.
45
How are ignition exciter unit and spark igniters powered?
From the BATT BUS.
46
How are fire/overheat detectors 1 and 2 supplied with power?
Through BATT BUS.
47
How is the engine air intake bypass as well as the INTAKE switch powered?
From the emergency bus.
48
What is the freedom of movement of the PCL?
- Free to move forward from FUEL OFF to MAX
| - Unintended movement of the IDLE position is prevented by a detent.
49
How can the PCL be moved aft of IDLE to FUEL OFF?
Safety catch must be released and the IDLE detent release lever must be raised.
50
What occurs in the FUEL OFF position?
The PCL cuts off the engine fuel supply mechanically.
51
What system allows for adjustment of the force needed to move the PCL?
Friction Control knob.
52
What may occur if the friction control is too loose?
The PCL might reduce under g.
53
Why are the IGN and STARTER switches magnetically latched?
1) Allow both front and rear cockpits full control over the system
2) A solo pilot in the front set to correct an incorrect selection in the rear cockpit
3) Instructor in the rear cockpit to override a selection in the front cockpit.
54
What is the position of the IGN and STARTER switches for normal operation?
AUTO
55
What will occur is both IGN and STARTER switches are set to AUTO and the system is not operating?
1) Selection to ON in either cockpit will cause the system to operate
2) Selection to OFF will prevent auto operation of the system.
56
What will occur is both IGN and STARTER switches are set to AUTO and the system is operating?
1) A selection to ON in either cockpit will prevent the system turning off
2) A selection to OFF in either cockpit will turn the system off.
57
What can the pilot do to fix an incorrect selection in the rear cockpit?
Select the front switch to ON (or OFF), rear switch will snap to auto and the pilot can now operate the switch as required.
58
What 2 modes of engine starting can be selected using the PMS switch?
1) Auto
| 2) Manual
59
What is not provided in PMS Manual mode during engine start?
Automatic limit exceedance protection and no auto dry run.
60
What should be selected for engine starting?
1. Mission Computer selected to ON
| 2. MFD ENG page should be selected (will appear automatically as well when starter is activated)
61
Can the EMD be used to monitor engine start?
Yes
62
What is ground idle and why is it there?
IDLE power setting when weight is on wheels. Used to prevent excessive braking while maneuvering on the ground.
63
What is minimum ground idle NG value?
54%, but it varies with ambient conditions.
64
When is engine max power limited to 1080 SHP?
1. When wheels on ground (WOW) is activated.
| 2. At airborne airspeeds lower than 80 KIAS
65
What occurs to max available power above speeds of 80 KIAS?
Available power increases progressively to provide max power of 1600 SHP at speeds above 200 KIAS.
66
What is the trend with max available power as airspeed increases?
Reduces according to PMU schedule.
67
What is Flight Idle NG value?
80%
68
When does flight idle provide zero thrust?
1. Clean aircraft configuration
| 2. Aircraft gliding speed of 140 KIAS
69
What commences the auto start sequence when STARTER and IGN are selected to AUTO?
AUTO START button.
70
What two things must be present for AUTO START to occur?
1. PMS must be ON
| 2. PCL at FUEL OFF
71
What will occur after engine has automatically shut down if limits are exceeded?
Auto dry run of 10 to 30 seconds.
72
What is AUTO START sequence?
1. Mission Computer selected to ON
2. MFD ENG page selected
3. Press AUTO START button
4. When NG is above 13% move the PCL to IDLE and monitor the ITT and NG.
73
What should NOT be done during start sequence?
Do not alter the starting mode during the start sequence.
74
What will occur within 20 seconds of depressing the AUTO START button if the PCL has not been moved to the IDLE position?
Starter will stop automatically.
75
How long should you wait for starter to cool before starting another engine start?
1 minute.
76
When should a 30 minute cooling period be had?
After 3 cycles of the starter motor.
77
What should be done before attempting an engine start with a low BATT 1 voltage?
Recommended to shed all unnecessary loads (such as the mission computer).
78
What is the min OAT to perform an engine start on internal power? What is the min BATT 1 voltage for successful start at this temperature?
- 10 C
| - 24.3 V
79
What is min temperature limit for GPU assisted engine start?
-40 C
80
Why is a dry run performed?
To reduce heat build up inside the engine during shutdown.
81
Which section of Flight Manual should be referred to for detailed information regarding power plant limitations?
Volume 1, Section 5 (Operating Limitations)
82
What warnings/advisories will occur if PMS is in manual mode?
- PMS caption on DWP
| - PMS Manual on MFD ENG page
83
What can occur if the PCL is moved too quickly?
Cause the ITT to exceed limits/cause the engine to surge.
84
What steps should be taken for a manual start?
1. PMS button pushed to enter manual mode.
2. Booster pumps L and R selected to ON position.
3. STARTER switch set to MAN position.
4. When Oil Pressure starts to rise, select ignition switch to ON.
6. When NG reaches 13%, move the PCL slowly forward.
7. As soon as fuel flow is indicated to the ITT increases, stop the PCL movement and wait until the ITT is not increasing anymore.
8. When the ITT starts to decrease again, continue to move the PCL forward very slowly.
9. Continue this way until the PCL reaches the IDLE detent.
10. Once the engine has reached IDLE NG, with the PCL above the IDLE detent, return starter, ignition and fuel pump switches to AUTO.
85
What is main indication to monitor manual engine start?
ITT
86
What should be ITT engine limits be carefully maintained within?
1) For a max of 20 seconds, ITT values can be between 860 C and 910 C
2) For a max of 5 seconds, ITT temps can be between 910 C and 1000 C
87
What are minimum IDLE NG values ?
60% and 74%.
88
What should occur if ITT or NG limits are exceeded?
1. Shut down the engine.
| 2. Carry out ENGINE DRY RUN before attempting another engine start.
89
When is a red FIRE warning displayed on DWP and MFD?
In case of an engine compartment fire or overheating.
90
When is a red OIL caption shown on DWP with a red OIL PRESS warnings on the MFD?
1) Oil Pressure is > 199 psi
2) Oil Pressure is > 130 psi for > 20 seconds
3) Oil pressure is < 70 psi for > 20 seconds
91
When is a red OIL TEMP warning shown on the MFD?
1) Oil temperature is > 110 C
2) Oil temperature is < -40 C
3) Oil temperature is > 105 C for > 10 minutes.
92
When is a red ENG ITT warning shown on the MFD during the start sequence?
1) ITT is > 1000 C
2) ITT is > 910 C for 5 seconds
3) ITT is > 860 C for > 20 seconds
93
During normal operations of engine, when is a red ENG ITT warning shown?
1) ITT > 910 C
| 2) ITT is > 860 C for > 20 seconds
94
When is a red ENG NG warning shown on the MFD?
If the gas generator speed is > 104% for > 2 second.
95
When is a red ENG TORQUE warning shown on the MFD?
If the PMS is in AUTO mode and either of following conditions apply:
1) Torque > 4874 ft lb
2) Engine torque is > 4202 ft lb for > 20 seconds.
3) PMS is in manual mode and torque is > 4202 ft lb.
96
During start sequence when is an amber ITT caution shown?
1) ITT > 910 C
| 2) ITT > 860 C for > 5 seconds
97
During normal operations, when is an amber ITT caution shown?
1) ITT is < 350 C
| 2) ITT is > 860 C for > 5 seconds
98
When is an amber ENG NG caution shown on the MFD?
- Engine is not in start mode for more than 4 seconds or it not shut down, and the engine NG is < 50.7%
- Engine gas generator speed is > 104 %
99
When is the amber STARTER caution shown on the MFD?
If the starter motor remains engaged after the engine has started.
100
When is an amber I-BYP FAIL caution displayed on the MFD?
1) The INTAKE button is pressed on the DE-ICE panel, but the intake bypass door does not move to its open position within 10 seconds.
2) When INTAKE door is open and is selected to close and the door fails to move its closed position within 2 seconds.
101
When is an amber CHIP AGB caution shown?
1) If there are metal particles in the accessory gearbox.
102
When is an amber OIL PRESS caution shown on the MFD?
1) Oil pressure is > 130 psi
2) Oil pressure is > 125 psi for > 55 seconds
3) Oil pressure is < 90 psi for > 10 seconds with the engine NG > 72% and g > 10
4) Oil pressure is < 70 psi for > 10 seconds
103
When is an amber OIL TEMP caution displayed on the MFD?
1) Oil temperature is > 105 C
| 2) Oil temperature is < 10 C
104
Where are the Engine Operating Limits found?
AFM Vol. 1 Section 5
