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39 Cards in this Set
- Front
- Back
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how much fuel do the wing tanks hold?
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131 gallons
- 40 gallons - 25 gallons - 23 gallons |
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how much does the center tank hold?
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44 gallons
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how much fuel does that nacelle tank hold
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61 gallons
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what happens if the 51 and 59 gallon float switches fail?
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fuel will over flow and flow back into the wing tanks via vent lines
operation stabilizes into a continuous fuel transfer loop this is indicated by a constantly full nacelle tank on the gauges |
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what happens when you place the transfer pump switch to override?
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the transfer pump shutoff circuits on the float switches are bypassed
operation stabilizes into a continuous fuel transfer loop this is indicated by a constantly full nacelle tank on the gauges |
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what happens when the transfer pump fails in flight?
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as the nacelle tank reaches 3/8 (150 gallons) full a gravity feed port opens and allows fuel to gravity feed from wing tanks
nacelle tank gauge will read 150# and in the yellow during this - fuel is only transfered at a reduced rate 28 gallons of fuel will not transfer from center tank while gravity feeding |
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what happens when you place the tx pump - override
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overrides float switches
continuous fuel transfer |
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what happens when you place the tx pump - auto
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transfer pump is activated by float switches
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what happens when you place the tx pump - off
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deactivates tx pump
fuel is gravity feeding |
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what are the different float switches
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59 g - turns off tx pump
51 g - turns off tx pump 42 g - turns on tx pump |
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what's the tx pump rated at?
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500 pounds/hour
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what happens if the circuit for the tx pump goes out?
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the tx pump and light won't work
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what happens if no pressure is passing by the fuel pressure sensing switch
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after 30 seconds the NO FUEL TRANSFER light will go on
the tx pump will be deactivated |
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what happens if the tx pump light goes on before the wing tanks are empty?
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tx pump malfunction
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what does the boost pump do?
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delivers pressurized fuel to the inlet of each engine driven fuel pump
powered by the fuel bus and hot batt bus |
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how do you tell a failed boost pump with the crossfeed in auto?
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- quick flash of the FUEL PRESSURE LIGHT
- Fault Warning - close the crossfeed valve |
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how many boost pumps must be operating to take off?
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both
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what happens with a failure of the boost pump during a rapid climb out?
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causes a gradual power loss on engine beginning at 13,000 ft
the altitude that it will fail at depends on fuel temperature in the tank (the higher the temp in the fuel tank = the lower the altitude of power loss) complete power loss will occur if the climb is continued as pressure inside the tank decreases, trapped air in the fuel expands and creates cavitation when pressure stabilizes during level out, the excess air escapes from the fuel and the lost boost pump has less effect on the engine operations you can get max power up to 31,000 feet stabilization time is determined by rate of climb and fuel temp - so time can't be determined = usually a few minutes descents with a failed boost pump have no effect on the engine if engine power loss is experienced during climb out due to failed boost pump - you can get good eng.. performance by - initiating x-feed - reducing power - descending |
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what does crossfeeding do?
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allows one engine to receive fuel from opposite tank
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how is the crossfeed powered?
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dual powered by No. 1 fuel bus and hot batt bus
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what happens if you crossfeed too long? how do you fix it?
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fuel imbalance
- with the crossfeed valve open, close the boost pump with less fuel off |
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what if you are crossfeeding and you need to extend your range?
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you can suction lift using the engine driven fuel pumps, but only for 10 hours between boost pump overhauls
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what happens if you are crossfeeding with two working boost pumps?
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fuel may inadvertently start to crossfeed
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when does the crossfeed valve open when in auto?
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when boost pump pressure drops from 30 psi to 5 psi
a pressure relay switch activates the annunciator light and opens the crossfeed valve |
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what happens to the crossfeeding system if the fuel bus or pressure warning circuit malfunctions?
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crossfeed valve will not recieve signal to open
pressure light won't come on |
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when single engine crossfeeding, what happens if the feeding tank goes empty?
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both engines will flameout
fuel quantity indication may be erroneous |
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Firewall shutoff valve
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provides electrical fuel shutoff to each firewall
receives power from fuel bus and hot batt bus |
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what happens if you close the firewall shutoff valve with both engines running
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will damage and cavitate the engine driven fuel pumps
they are lubricated by the fuel |
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tell me about the fuel heater
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uses heat from eng. oil supply system to preheat engine fuel
the temp. sensing oil bypass valve regulates the oil and start to close at 70*F while simultaneously closing the core valve oil is completely bypassed at 90*F |
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Engine driven fuel pump
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mounted on the accessory section of the engine
operates anytime the gas generator (N1) is turning provides fuel for start, t/o/ and all flight conditions limited to 10 hours in suction lift relies on fuel for lubrication failure = flameout rated at 800 psi |
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what does the fuel control unit do?
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determines the fuel schedule for the engine to prevent compressor stall or excessive ITT based on power lever
- N1 speed is controlled by varying the amount of fuel injected into the combustion chamber - changes in engine inlet temp. vary eng. characteristics and call for adaptive fuel schedules - which the FCU computes and meters fuel flow required to maintain constant idle speed decreased with altitude - above 3500 feet, idle speed can be as high as 83% - also receives secondary input via the SCU through the condition levers |
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what does the purge valve do?
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opens during the start cycle (when ignitors are on) and returns fuel vapor trapped in FCU to the nacelle tank
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what does the fuel drain collector pump/tank do?
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transfers residual fuel back to the fuel supply
fuel drains into collector tank from flow divider located below the accessory section a float switch activates the pump when the tank is full and fuel is returned to the supply |
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where are the fuel tank sump drains located?
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5 on each engine - they drain moisture and sediment
- nacelle tanks - wing tanks - wheel well sumps - transfer pumps - fuel strainers in eng. compartments |
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what do the fuel vents do?
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relieve pressure in the tanks caused by thermal expansion
protected from icing by electric heaters |
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what is min fuel?
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265#
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what is the total fuel/ usable fuel?
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387.6
384 |
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what is different about the right system?
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contains - crossfeed valve
- thermal relief valve - thermal relief line from crossfeed line |
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what kind of gas are you allowed to use
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Jet A/A1/B
JP 4/5/8 AV Gas (PWA Spec no. 522 and later) av gas limited to 150 hours |
