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13 Cards in this Set
- Front
- Back
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Briefly describe the fuel system on the DA42.
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-There are 4 fuel tanks totaling 76.4 usable gallons of JET A.
-2 main tanks with 25 usable gallons each -2 aux tanks with 13.2 usable gallons each -The main tanks are made of aluminum and are composed of 3 chambers joined by rubber hoses. -The aux tanks are made of aluminum with baffles on the inside to prevent rapid fluid movement. |
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How much does jet fuel weight at standard temperature?
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7.01 lbs (@ 15° C)
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What temperature does JET A freeze at?
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Jet A freezes at -40°C
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Describe the main fuel tanks and their components.
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-The main tanks are made of aluminum and are composed of 3 chambers joined by rubber hoses.
-The fuel quantity probes are in the inner and outer chambers, not middle. -The outer chamber has the tank filler, tank vent and check valve. The inner chamber has the fuel temperature sensor, low level fuel switch, and the fuel supply/return connections -With the aux tanks installed, the outer high level fuel switch is used to stop aux fuel pump when main is full. The inner switch not currently used, according to maintenance manual. |
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How do the low level fuel sensors work?
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They are float based. The floats will drop with decreasing fuel. At 3-4USG, the float operates a micro switch which activates the low fuel indication in the cockpit.
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Why should the engines not be shut off by moving the fuel selector to off?
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Shutting down the engine with the selector valve can cause damage to the high pressure fuel pump.
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With the fuel selector in the on position, what is the flow of the fuel?
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Fuel is drawn from tank, into the engine, returned through the fuel cooler to the engine tank.
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With the fuel selector in the x-feed position, what is the flow of the fuel?
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-Moving the fuel selector to the x-feed position disables flow to and from the associated tank. The engine pump takes fuel from opposite tank.
-The returned fuel is supplied back to the tank from which it was taken. -The fuel will flow through the cooler on the side from which the fuel was taken. |
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If the RH engine has failed. How do you get fuel from the right tank?
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With the RH engine failed, set the left fuel selector set to x-feed.
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Why is a fuel cooler necessary on this aircraft?
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A bi-product of compressing something is it gets hotter. Because the fuel is compressed to a high pressure, it also gets heated. The excess fuel that is not used in the common rail fuel injection system needs to be cooled before it goes back into the fuel tank. If it doesn't, the fuel could get too hot and turn into vapor causing vapor lock.
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How do you use the fuel from the aux tanks?
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-Turn on the aux transfer pumps. These transfer fuel to the main tanks via the main fuel return line after the fuel cooler.
-The fuel passes through the fuel filter, then the aux fuel pump, then a pressure check valve. -The pumps shut off when the fuel level too low, or the main tank is full. |
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How fast do the aux fuel transfer pumps transfer fuel?
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1 gal per minute
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How do you know when the aux tanks have finished transferring?
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-Caution Annunciation on the PFD. If the auxiliary tank is empty: ‘L/R Aux Fuel E’
-Transfer pump must be turned off now. -This will take about 13 minutes. |
