PC-21 Fuel System Flashcards
What is the purpose of the fuel system?
1) To safely store the fuel required for a mission in internal and external tanks
2) Supply clean fuel to the engine at the required pressure and flow rate during all phases of flight and all maneuvers
3) Provide the pilot with sufficient information on fuel system status and fuel quantity available to aid decision making and successful mission completion.
How is the fuel system designed to operate?
Automatically
Will the centre of gravity remain within limits no matter the state of the aircraft?
Yes
What is the usable internal fuel capacity of the aircraft? Or what is the weight capacity of the PC-21 integral tanks and collector tanks combined?
Review Q
1200 lb.
What fuel tanks does each wing contain and how is it held in the wing?
- Wing tank and collector tank in each wing
- Wing structure forms the wall of these tanks, which prevent the fuel from moving around in flight.
Where is the aerobatic tank located and what is its purpose?
- Lower left side of the forward fuselage.
- Supply a continuous supply of fuel to engine under negative g conditions.
What is the capacity of each collector tank?
53 lbs
What is the capacity of each wing tank?
547 lbs
What do the four flapper valves in the middle of each wing tank allow for?
- Fuel to flow inboard
- Prevent fuel from flowing rapidly in the opposite direction
What doe the flapper valves installed between the wing and collector tanks allow for?
Allow fuel to be gravity fed from the wing to the collector tank and prevent fuel flowing back into the wing tank.
What is the capacity of the aerobatic tank?
Review Q
23 lbs for max 45 seconds under negative g
Where does the aerobatic tank get fuel from and then send it to?
- From collector tanks
- To Fuel Filter
What does the bleed line in the aerobatic tank do?
Ensures that any air in the aerobatic tank can be vented back to the tanks.
How does the aerobatic tank work?
- Y shapes suction pipe with two gravity controlled flapper valves so that only one is open at a time during +ve g and -ve g.
What do the drain valves allow for?
Fuel to be drained from the tanks and fuel filter and checked for contamination.
Where are the two wing tank drain valves located?
- Mounted on the bottom surface near the center of each wing.
Where are the two collector tank drain valves located?
Installed on the bottom surface of each wing, near the wing root and close to the leading edge.
Where is the drain tank for the aerobatic and fuel filter?
On the bottom of the aerobatic tank.
What do the wing tank air vents allow for?
- Air to flow into or out of the tanks as fuel is used, or during refueling or defuelling.
- Prevention of high differentials between fuel tank internal and ambient atmospheric pressure when altitude/temperature change.
- Maintenance of same pressure on both sides of the fuel system.
Where are the inlets and outlets of vents located?
- 2 inlets are located on each wingtip.
- 2 outlets are located under the tail of the aircraft.
What does the fuel filter do?
Removes solid particles and water from the fuel.
What does the firewall shut-off valve do?
In the event of a fire in the engine, the FSOV can be closed in order to cut off the fuel supply to the engine.
What does the fuel low-pressure switch do?
Senses the pressure in the fuel supply line and sends signals to the FCMC.
What does the engine driven fuel pump do?
- Provides fuel to the engine high pressure pump
- Motive flow for the ejector pumps.
What do the transfer ejections pumps to?
Feed fuel from the wing tanks to the collector tanks and from there, to the aerobatic tank.
When does the booster pump operate and what is its flow rate?
- During Engine Start
- After inverted flight of > 5 seconds to refill aerobatic tank
3 When inlet pressure to the engine-driven fuel pump is low as sensed by the fuel low pressure switch downstream of the firewall fuel shutoff valve - To correct fuel tank imbalances of more than 55 lb
- When the fuel filter is blocked
Flow rate of 660 lb/hr.
What measures the level of fuel in the wing tanks and collector tanks?
- 4 fuel volume probes in each wing tank
- 1 in each collector tank.
How many low level sensors are installed in each wing tank and what do these do?
- 2 in each wing tank.
- Send a signal to the FCMC of low fuel level, which then sends fuel quantity signals to the EMD and MFD
- Measure fuel temperature
What are the ENGINE fuel controls in the cockpit.
- EXT L and EXT R switches
- PUMP L and PUMP R booster pump switches
- Emergency jettison switches
- FUEL/HYD shutoff handle
Where are fuel system indications shown?
- EMD
- MFD FUEL
- DWP
- UPCP
How can the internal tanks be refueled?
- Single point pressure refueling, located on the pressure refueling service panel in the lower right fuselage, behind the wing. Rate is 320 lbs/min.
- Through gravity refueling with a filler cap that is located at the highest point in the wing tank towards the front of the wing.
How is fuel transferred from wing tanks to engine?
By pumps and by gravity from wing tanks –> collector tanks –> aerobatic tanks
What pumps feed fuel from wing tanks to collector tanks?
Two transfer ejector pumps
What pumps feed fuel from collector tank to aerobatic tanks?
One engine-feed ejector pump.
What is the max flow rate of the transfer ejector pumps?
500 lb/hr
What is the max flow rate of the engine-feed ejector pumps?
750 lb/h
How does fuel flow after the aerobatic tanks?
- Through fuel filter
- Through fuel shut off valve
- To engine driven fuel pump.
What is the max fuel flow rate of the engine-driven fuel pump and where does excess fuel fo?
- 3200 lb/hr
- Back to collector tanks
What does the FCMC do during maneouvres?
- Takes into account fluctuating fuel quantity measures by monitoring aircraft acceleration data fro the inertial reference unit.
- Inhibits low level fuel indications when A/C acceleration is excessive.
When is the low level fuel caution warning generated?
When bot the inner and outer low-level sensor in each wing tank fall dry, indicating that fuel level in each tank is < 70 lbs
Which MFD pages are fuel indications provided on?
- MFD FUEL
- MFD SYS
- MFD ENG
- MFD NAV
What fuel info is provided on the MFD FUEL page?
- Fuel Flow (lb/hr)
- Detotaliser (DETOTE) fuel quantity
- Total INTERNAL fuel quantity
- Endurance (END) at current fuel flow
- JOKER and BINGO fuel
What fuel info are shown in the MFD NAV page?
- Total fuel
- JOKER and BINGO fuel values
- END at current fuel flow
- Estimated Fuel at Steer point (EFS)
- Estimated Fuel Remaining
What fuel info is shown on the MFD SYS page?
- Fuel Flow (FF) in lb/h
- Detotaliser (DET) fuel quantity
- Total internal (INT) fuel quantity
- Total (TOT) fuel
- Booster pumps operating status (PUMP)
- External fuel transfer pumps status (EXT)
What fuel info is shown on the MFD ENG page?
- Fuel Flow
- Booster pumps operating status
What info does the EMD show?
- Total internal fuel quantity
- Left and right internal fuel quantities
- FF in lbs/hr
What are the functions of the FCMC?
- Internal tank fuel quantity measurement
- Internal tank fuel temperature measurement and density calculation
- Internal tank low level fuel sensing
- Fuel quantity output in the correct units
- Monitoring fuel pressure and filter blockage
- Controlling booster pumps operation in auto mode
- Controlling internal fuel balancing in auto mode
- Triggering fuel system warnings and captions.
How are the booster pumps powered?
From the BATT BUS
How is the FCMC powered?
From the BATT BUS
What are the two modes of operation for the fuel system and how are they activated?
- AUTO and MANUAL
- AUTO is when Booster pump and External pumps switches are set to auto
- Manual mode is used for manual engine start and when AUTO mode fails.
- Manual mode is entered when booster pump switches are in the PUMP L/PUMP R or OFF position.
What responsibilities does the pilot have to in Manual fuel mode?
- Ensure the pumps are selected on when required to maintain pressure and flow rate
- Off when running dry.
What captions are displayed on the DWP and MFD FUEL page when the booster pumps are operating?
- F-PMP on DWP
- TRANSFER
Do booster pumps activate in inverted flight?
No.
Why are the booster pump switches magnetically latched?
To enable:
1. Both front and rear pilots to have full control over each system
2. A solo pilot in the front seat to correct an incorrect selection in the rear cockpit.
3. An instructor in the rear cockpit to override a selection in the front cockpit.
How to correct an incorrect selection in the rear cockpit?
Selection PUMP L/R or OFF and rear switch will snap to AUTO.
What is the UFCP FUEL page used for?
- To enter, edit or reset fuel reminders for the current mission, such as BINGO, JOKER and DETOTE fuel values.
What will occur at BINGO and or JOKER fuel states?
The pilot will be alerted.
What is the default BINGO alert level?
350 lb
What is the default JOKER alert level?
450 lb
How can the BINGO and JOKER values be changed?
On UFCP
What is the DETOT fuel?
The gauges total fuel quantity at startup.
What should be done in the event of an engine fire?
- Pull FUEL/HYD CUT OFF
- Turn off Booster pumps.
When does the amber FPR FUEL PRESS caution occur?
When the fuel pressure measured at the fuel low-pressure switch is less than lower limit for < 2 seconds.
When does the amber FPR FUEL PRESS caution turn red and a FPR warning caption is shown on the DWP?
- When 2 seconds have elapsed and the fuel pressure is still less than the specified lower limit.
What are two potential causes of fuel low pressure?
- If the engine driven fuel pump or mechanical drive from engine accessory gearbox fails
- A leak in the fuel supply line.
What cautions are displayed when both low-level sensors in a wing tank are dry?
- Amber FUEL caption is displayed on the DWP
- FUEL L LOW or FUEL R LOW caution is displayed in the MFD alerting area.
What occurs with a fuel imbalance of 121 lb existing between the left and right wing tanks?
Amber FUEL IMBALANCE caution will be displayed on MFD FUEL and MFD alerting page.
What caution is displayed if the FCMC fails?
- FUEL COMPUTER caution is displayed in the MFD alerting area.
- FUEL COMP caption is shown on the MFD FUEL page.
What functions will be lost in the event of FCMC failure?
- Automatic booster pump control
- Automatic balancing
- Automatic external tank transfer.
When are JOKER or BINGO cautions displayed?
If the internal gauged fuel is less than the value set on the UFCP.
What occurs on the displays if the fuel filter is blocked?
- FUEL FILTER caution is indicated on the MFD FUEL page as well as in the MFD alerting area.
- Accompanied by green F-PMP caption showing booster pumps are on.
Which of the following routes does the fuel flow tank from the tanks to the engine?
Wing tanks –> Collector tanks –> Aerobatic tank –> Fuel filter –> Firewall shut off valve
What happens when there is a fuel imbalance of 55 lbs between LH and RH tanks?
The booster pumps are activated by the FCMC in Auto mode and a Green F-PMP caption display will be shown on the DWP.
If the quantity of imbalance continued to increase at what quantity imbalance would the FCMC automatically shut off the boost pump?
At 121 lb or more with an orange Fuel imbalance caption.
What colour light illuminates and displays F-PMP on the DWP when the boost pumps are operating?
Green
Where would you find fuel flow and internal fuel quantity displayed together?
MFD Fuel, MFD SYS, EMD
The Fuel Control and Monitoring Computer (FCMC) feeds information to what displays and Panels?
EMD, PCL, Fuel panel, engine panel, DWP and (only to MFD through the MC)
What fuel information changes are carried out on the Up-Front Control Panel (UFCP)
Bingo, joker, detote and reset