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The indication of a fuel float gauge varies with:

1 – pitch angle
2 – accelerations
3 – fuel temperature.

The combination that regroups all of the correct statements is:

  • A
    1, 2.
  • B
    1, 2, 3.
  • C
    2, 3.
  • D
    1, 3.

The float-type fuel gauging system consists of a simple mechanical float sitting on the fuel level, linked via a mechanical arm to a gauge indicating the volume. One of the main limitations of the volume indicating systems is that temperature variations will impact the reading of the tanks’ actual fuel quantity. In fact, at warm temperatures, fuel is heated up and expands. Since the volume of fuel is increasing, the float-type gauge indicates an increase of fuel quantity within the tanks. The reading will also be imprecise during maneuvers (pitch angle changes), accelerations, and turbulence; the reading will only be reliable in straight and level flight.

To overcome this problem, modern capacitor-type fuel gauging systems are fitted with a density compensating unit, which accounts for the temperature changes by converting the output from volume to mass of fuel.

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