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Position indication on hand-operated fuel valves

Aviation Mechanic Airframe (AMA) practice question 3 of 12 on Aircraft Fuel Systems. ACS element AM.II.J.K1 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic Airframe (AMA) practice mode.

Question bank updated 2026-09-22

QUESTIONHand-operated fuel valves in an aircraft fuel system give positive indication of valve position by means of what feature?

  1. APosition annunciator lights on the flight deck
  2. BA thermal relief bypass around the valve seat
  3. CDetents that a spring-loaded pin drops into
Show the answer and explanation

Correct answer: C. Detents that a spring-loaded pin drops into

  • A — incorrect Position annunciator lights are used with motor-operated and solenoid-operated valves, which are not directly visible or felt by the operator.
  • B — incorrect A thermal relief bypass relieves pressure that builds against a closed gate as temperature rises; it has nothing to do with showing valve position.
  • C — correct Hand-operated valves accomplish positive position identification through detents into which a spring-loaded pin or similar protrusion locates when the valve is set in each position.

BACKGROUND

A feature of all aircraft fuel valves is a means of positively identifying the position of the valve at all times. On light aircraft the selector valve combines the shutoff and tank-selection functions in one unit, while large aircraft use many valves named for their job, such as shutoff, transfer, and crossfeed valves. Fuel valves may be manually operated, solenoid operated, or driven by an electric motor. Hand-operated valves use detents together with labeling and a directional handle so the position can be confirmed by both feel and sight. Motor- and solenoid-operated valves instead report their position with annunciator lights, and flight management system fuel pages can display valve position graphically.

STUDY TIP

Sort fuel valves by how they are actuated first, then recall the position-indicating method that goes with each kind of actuation.

KEY POINTS

  • Hand-operated fuel valves lock into position with detents and a spring-loaded pin.
  • Labels and a directional handle let the position be confirmed by feel and by sight.
  • Motor- and solenoid-operated valves use annunciator lights instead.

SOURCES

  • sources/ama-airframe/ch14.txt, "Fuel Valves"
Practice the Aviation Mechanic Airframe (AMA) test →Timed 100-question exam, by ACS area, or review your misses. Free.
MORE ON AIRCRAFT FUEL SYSTEMS

SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-31B Aviation Maintenance Technician Handbook – Airframe, and 14 CFR part 43. Regulations and handbooks are revised; confirm details against the current edition.