Aircraft Electronics Technician AET - NCATT

NCATT Aircraft Electronics Technician (AET) Study Guide
• Voltmeter
o Used to find a circuit problem with power on the circuit
o When checking for zero output voltage, a good starting point is to check the input
with a voltmeter
• Ammeter
o Used to find a circuit problem with power on the circuit
o Millimeters and micro ammeters measure very small rates of current flow
• Ohmmeter
o Used to find a circuit problem when power is removed from the circuit
o Ohmmeters measures resistance
• Oscilloscope
o Measures and displays voltage (AC peak-to-peak values) in waveforms (output)
of a wave generating circuit
o See Use Test Equipment/Special Tools
Basic Troubleshooting Theory:
• Continuity Check/Test
o Checks for the existence of a complete electrical system between two points
o Most of the time, a voltmeter or ohmmeter is used to test the continuity of a
circuit
o Tests should be made at each terminal of the circuit to isolate the problem
Steps in the Troubleshooting Process:
• Isolate the problem
o Is the equipment being operated properly
o Is the problem ongoing
o Is the problem intermittent
o Is the problem worse during taxi
o Is the problem worse during takeoff
o Does the problem exist while cruising
o Is the problem worse during landing
o Is the software loaded properly
o What impact does weather have on the problem
• Check for the obvious
o Are there any loose connections
o Loose or broken wiring
o Bent or Frayed wiring
o Inoperative indicator lights
o Are there bad electrical bonds
o Broken or cracked parts
o Anything punctured
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