FAA Aviation Mechanic Airframe (AMA)Fuel, Cabin and Ice Control SystemsEasy

A line technician needs to manually verify the fuel quantity in a large transport aircraft's wing tank because the capacitance-type indicating system is temporarily inoperative. Which device is inserted through a calibrated opening in the tank to physically measure fuel level?

  1. AFuel quantity compensator tube
  2. BFloat-type indicator arm
  3. CCapacitance probe
  4. DMagnetic drip stick
Show answer & explanation

Correct answer: D. Magnetic drip stick

A magnetic drip stick is inserted through a calibrated sump opening until a magnet on its end engages a float inside the tank; the reading on the graduated stick indicates fuel quantity in gallons or pounds, providing a manual backup to electronic fuel quantity systems.

Why the other options are wrong

  • A. The compensator tube corrects capacitance readings for fuel dielectric changes, not a manual dipstick.
  • B. Float-type indicators are electromechanical, not hand-inserted sticks.
  • C. A capacitance probe is part of the electronic system, not a manual backup tool.

Magnetic Drip Stick

A calibrated stick inserted through a tank sump opening that uses a magnetic float to physically indicate fuel quantity, serving as a manual backup to electronic fuel gauges.

  • Inserted through a calibrated tank access point
  • Magnet engages internal float at fuel surface
  • Provides manual cross-check for capacitance systems

Memory trick: 'Drip stick dips down to find where the fuel sits.'

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