Diagnostic and Testing Tools Flashcards
7 cards from real AET practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Diagnostic and Testing Tools flashcards as text
When measuring resistance in an installed aircraft circuit with a digital multimeter, the technician must first:
Answer: De-energize the circuit and discharge any capacitors
Measuring resistance in a live circuit will give inaccurate readings and can damage the meter; the circuit must be de-energized first.
Which of the following best describes the function of a BITE (Built-In Test Equipment) system?
Answer: Onboard self-test circuitry that monitors and reports system faults automatically
BITE is embedded within avionics units to continuously or on-command perform self-tests and store fault codes for maintenance retrieval.
A technician uses an oscilloscope to observe a 400 Hz aircraft power bus waveform and notices the top of the sine wave is flattened. This condition is called:
Answer: Clipping or waveform clipping
Clipping occurs when a signal exceeds the linear range of a component or supply, causing the peaks to be cut flat.
The correct procedure when using a megohmmeter (megger) to test aircraft wire insulation is to:
Answer: Disconnect components from the wire under test to avoid applying high voltage to sensitive avionics
Megohmmeter test voltages (typically 500–1000 V) can permanently damage solid-state avionics connected to the wire under test.
When calibrating a pressure transducer used in an aircraft fuel quantity system, which test equipment is most appropriate?
Answer: Dead-weight tester or precision pneumatic pressure calibrator
A dead-weight tester or precision pneumatic calibrator provides traceable reference pressures needed to verify and adjust pressure transducer accuracy.
An aircraft COM radio's audio output is distorted. The most effective first step using a digital storage oscilloscope is to:
Answer: Capture the audio waveform and compare it to a known-good waveform for clipping or noise
Capturing and visually comparing the audio waveform reveals the nature of distortion (clipping, noise, hum) to guide further diagnosis.
What does a high VSWR reading on an antenna analyzer indicate about an aircraft antenna installation?
Answer: There is a significant impedance mismatch causing reflected power
A high Voltage Standing Wave Ratio means reflected power is returning to the transmitter, indicating an impedance mismatch in the antenna system.