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Safety
What is the primary purpose of safety glasses when working in an aircraft maintenance shop?
To prevent eye injury from flying debris
Static electricity is most commonly produced by:
Friction between two unlike materials
What is the primary purpose of a circuit breaker in an aircraft electrical system?
A circuit breaker protects the electrical system by opening the circuit when excessive current flows, preventing wiring damage and reducing the risk of fire
What information does the wire identification code printed on aircraft wiring typically include?
include wire gauge (AWG), insulation type, and circuit function or number
What is the primary purpose of an electrical connector in an aircraft wiring system?
Electrical connectors allow quick connection and disconnection of wiring while ensuring a secure electrical path between components.
What is the primary purpose of safety wiring on aircraft hardware?
Safety wiring prevents nuts, bolts, and other hardware from loosening due to vibration
What does an AC voltmeter measure in an electrical circuit?
AC voltmeter measures the root‑mean‑square (RMS) voltage
When working around flammable solvents, which action helps reduce the risk of fire?
Keeping containers tightly closed when not in use
A buildup of electrostatic charge on an aircraft during flight is primarily caused by:
Friction between the aircraft and air particles
According to FAA electrical diagram conventions, what does a zig‑zag line represent?
A Resistor
According to FAA guidelines, what factor primarily determines the allowable current (ampacity) of an aircraft wire?
The allowable current is mainly determined by the wire’s gauge and insulation temperature rating,
What is one FAA requirement regarding the condition of connector terminals during inspection?
Connector terminals must be free of looseness, corrosion, discoloration, or overheating,
According to FAA‑approved practices, why should safety wire and cotter pins never be reused?
Safety wire and cotter pins must not be reused because once bent or stressed, they lose their original strength and reliability, risking component loosening.
Why must an ohmmeter never be connected to an energized circuit?
ohmmeter contains its own internal battery and applying external voltage can damage the meter movement and produce incorrect readings.
Foreign Object Damage (FOD) in a maintenance shop is best prevented by:
Keeping the work area clean and accounting for tools and hardware
What is the purpose of static discharge wicks installed on aircraft trailing edges?
To dissipate static electricity into the atmosphere
What is the function of a bus bar in an aircraft electrical system diagram?
A bus bar serves as a central distribution point that supplies power to multiple circuits or components
Why is wire bundle size important when selecting wire for an aircraft electrical system?
wire bundles restrict airflow and trap heat, requiring technicians to derate (reduce) allowable current for wires located inside the bundle.
Why must connectors be installed so that their wiring is adequately supported?
Connectors require proper support to prevent strain, chafing, and mechanical stress
Why is it important to use the correct torque value when tightening aircraft bolts?
Using correct torque prevents over‑torquing, which can weaken or damage the bolt, and under‑torquing, which can allow joint movement or failure.
What does a “high‑resistance reading” typically indicate when troubleshooting a circuit?
A high resistance reading often indicates poor connections, corrosion, loose terminals, or damaged wiring
If a mechanic’s clothing becomes soaked with fuel or solvent, the mechanic should:
Immediately remove the clothing and wash affected skin
Which statement concerning magnetic fields is correct?
Magnetic field lines flow from the north pole to the south pole outside the magnet
What is the primary function of a relay in an aircraft electrical system?
A relay allows a low‑current control circuit to switch a high‑current load
According to AC 43.13‑1B, why must aircraft wiring be routed clear of control cables and moving components?
Wiring must be routed away from moving controls to prevent chafing, abrasion, and possible short circuits
What is one FAA‑approved method for preventing moisture intrusion into electrical connectors?
environmentally sealed connectors or applying appropriate backshells and grommets
What is the purpose of using the correct safety‑wire direction when securing hardware?
Safety wire must be installed so that it pulls the fastener in the tightening direction, preventing loosening during vibration and ensuring the fastener cannot rotate counterclockwise.
When troubleshooting a circuit that shows no continuity where continuity should exist, what is the most likely cause and what measurement should you take next?
open circuit
When working on aircraft electrical systems in a maintenance shop, what is the first step that should be taken before performing maintenance on the circuit?
Turn off and secure the electrical power source
When an electric current flows through a conductor, the conductor:
Produces a magnetic field around it
What does a switch do in an aircraft electrical circuit?
A switch opens or closes an electrical circuit to control current flow to a component.
What is the FAA‑approved method for determining minimum wire size when both continuous load and intermittent load are present on the same conductor? Think about the wire selection charts
The minimum wire size is chosen using the highest expected current (including intermittent loads), derated for bundle conditions and temperature
Why is pin/socket alignment critical during connector assembly, and what can happen if misalignment occurs?
Proper alignment ensures correct mechanical engagement and prevents bent pins, high‑resistance contacts, or intermittent electrical faults that compromise system reliability
Torque Wrench is 10 inches long
Adapter is 2 inches long
Torque is 100 in-lbs
83.3 in-lbs
A circuit shows correct voltage at the power source, but when you test for voltage at the load with the circuit switched ON, the meter shows 0 volts. What does this indicate about the circuit, and what measurement should you take next to confirm the fault?
high‑resistance connection or an open circuit