Fuel Flashcards
Usable Fuel Capacity SR20 ?
56 Gal
Usable Fuel Capacity SR22
96 Gal
SR20 Tabs ?
26 Gal (13 per side)
SR22 Tabs ?
60 Gal (30 per side)
What’s the estimated range of the SR20 for 65% power 8000 feet ?
650 NM
Estimated Range of SR22 for 65% power at 8000 ft ?
~850 NM
Whats the Flapper Vale do ?
One way valve between main tank and collector tanks.
Why are there collector tanks ?
Less sensitive to maneuvers to provide immediate on-demand source of fuel.
Describe purpose of the selector valve.
Directs fuel flow from either left or right tank to the electric auxillary fuel pump and gascolator.
Describe purpose of gascolator.
Filters fuel down to 100 to 140 microns.
Describe Fuel flow leaving Gascolator
1) Then to engine-driven fuel pump
2) To mixture/throttle controlled metering valve (SR22) or Fuel Servo (SR20)
3) To flow divider to proportion fuel to injectors
Describe purpose of the Boost Pump
Used for engine priming and vapor surpression. Increases fuel pressure to 23 psi.
Describe purpose of fuel relay.
Governs speed (i.e. high/low) of fuel pump based on oil pressure of 10 PSI from EAU.
If oil pressure less than 10 psi, does prime work ?
No, pump will only run in “low” i.e. Boost. 23 psi.
Describe limits of primary fuel pump relating to atmopheric pressure.
Turbo version will dynamically vary fuel pump pressure based on manifold pressure. Other versions require pilot to control mixture on climb/take-off from high-altitude airports.
Describe purpose of mixture control.
controls RATIO of fuel to air to engine.
Describe purpose of Power-Lever.
Controls total VOLUME of fuel/air mixture.
Where is mixture control connected ?
Fuel Servo (SR20) or Throttle Metering Valve (SR22)
How is fuel quantity measured ?
Float sensors in each tank send values to EAU (Engine Airframe Unit)
What are the fuel CAS messages that could be received (Cirrus Perspective) ?
1) Yellow L Fuel Qty <8 Gal (SR20) < 14 Gal (SR22)
2) Yellow R Fuel Qty <8 Gal (SR20) < 14 Gal (SR22)
3) Yellow FUEL QTY Both Tanks < 8 Gal (SR20) < 14 Gal (SR22)
4) Red FUEL QTY BOTH TANKS < 7 Gal Total < 9 Gal Total
What are CAS fuel messages in Cirrus Perspective Plus ?
1) Yellow Fuel Low Total <10 Gal (SR20) < 14 Gal (SR22)
2) Red Fuel Low Total < 7 Gal (SR20) < 9 Gal (SR22)3) Yellow
3) FUEL LOW L < 1 GAL
4) FUEL LOW R < 1 GAL
How is fuel flow sensed ?
A transducer mounted downstream engine-driven fuel pump (SR22) and downstream of fuel-servor (SR20)
How do you supress fuel vaporization ?
Boost Pump will increase pressure to 23 psi, which delays onset of vaporization.
Does fuel vaporization occur to higher altitudes ?
Yes, it can be more pronounced, especially at high-altitudes on warm days.
Describe fuel flow on take-off / climb-out.
Too much fuel flow can create excessively rich mixture, compromising engine performance or cause roughess engine failure.
