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Dashed lines on modification schematics

Aviation Mechanic General (AMG) practice question 37 of 41 on Fundamentals of Electricity and Electronics. ACS element AM.I.A.K25 · difficulty: recall. Want to answer it in a timed quiz? Use the Aviation Mechanic General (AMG) practice mode.

Question bank updated 2026-09-22

QUESTIONOn a schematic prepared for an aircraft modification, what does a dashed line typically represent?

  1. ANew wires being added by the modification
  2. BA shielded conductor rather than a plain single wire
  3. CExisting wires installed prior to the modification
Show the answer and explanation

Correct answer: C. Existing wires installed prior to the modification

  • A — incorrect New wires added by the modification are drawn as solid lines, not dashed.
  • B — incorrect Shielding is shown by its own symbol around the wire, not by changing the wire to a dashed line.
  • C — correct Schematics used for aircraft modifications may use dashed lines for existing wires prior to the modification and solid lines for new wires.

BACKGROUND

The schematic is a diagram that depicts the interconnection and logic of an electrical or electronic circuit, and it is the most common place a technician finds electronic symbols. A conductor is generally shown as a solid line. Schematics used for aircraft modifications, however, may also use other line types, such as a dashed line to represent existing wires prior to the modification and solid lines for new wires. Schematics also show wire types such as single, shielded single, shielded twisted pair, and shielded triple, and usually carry wire numbers whose format varies by installation agency.

STUDY TIP

On a modification drawing, ask which wires are already on the aircraft: those are the dashed ones.

KEY POINTS

  • A conductor is normally a solid line.
  • Modification schematics: dashed = existing wire, solid = new wire.
  • Wire numbering formats vary by the agency that drew the prints.

SOURCES

  • FAA-H-8083-30B ch12 "Schematic Representation of Electrical Components" - "Conductors"
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SkyDrill is not affiliated with the FAA. This is an original practice item based on FAA-H-8083-30B Aviation Maintenance Technician Handbook – General, 14 CFR part 43 and part 65. Regulations and handbooks are revised; confirm details against the current edition.