Practice Test Geeks(AET) Aircraft Electronics Technician Practice Test
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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

  1. A technician uses a curve tracer to evaluate a transistor from an aircraft avionics power supply. Compared to a known-good device, the curves show early saturation at low collector voltage. This indicates:

    Answer: The transistor's collector-emitter breakdown voltage is reduced, suggesting a damaged junction

    Early saturation at low collector voltage on a curve trace is a classic sign of reduced breakdown voltage, indicating junction damage.

  2. When performing an ARINC 664 (AFDX) network test, a technician uses a network analyzer. Which parameter is most critical to verify for proper avionics bus operation?

    Answer: Bandwidth allocation gap (BAG) timing and jitter of virtual links

    AFDX relies on deterministic scheduling via BAGs; excessive jitter can cause data to arrive outside its time window, disrupting avionics communication.

  3. A technician performing a functional test notices an avionics unit fails its self-test only when the aircraft is at operating temperature. The best diagnostic strategy is to:

    Answer: Use a thermal camera or temperature-sensitive spray to identify heat-sensitive components while monitoring with a digital multimeter

    Thermal imaging or temperature spray helps isolate components whose electrical characteristics shift with temperature, causing the intermittent failure.

  4. On an oscilloscope, the term 'bandwidth' refers to:

    Answer: The frequency range over which the oscilloscope can accurately display signals (typically –3 dB point)

    Oscilloscope bandwidth is defined as the frequency at which displayed amplitude drops to –3 dB (about 70.7%) of the actual signal amplitude.

  5. A handheld RF power meter reads significantly lower output than specified when connected to an aircraft DME transmitter. After verifying meter calibration, the next most logical test is to:

    Answer: Check for excessive VSWR or cable loss between the transmitter and the power meter using a VSWR meter

    Cable loss or a high VSWR caused by a mismatched or damaged feedline can significantly reduce apparent transmitter output measured at the end of the line.

  6. During a flight data recorder (FDR) readout verification, which tool is used to replay and analyze the recorded parameters against the airframe's QAR data?

    Answer: Dedicated DFDAU/FDR replay software with the appropriate aircraft parameter conversion tables

    FDR data requires aircraft-specific parameter conversion tables loaded into specialized replay software to translate raw digital values into engineering units.

  7. What is the purpose of the 'hold' or 'freeze' function on a digital multimeter when taking measurements in an aircraft cockpit environment?

    Answer: It latches the displayed reading so the technician can read the value after removing the probes from an awkward location

    The hold/freeze function captures and displays the last measured value, allowing the technician to safely remove probes and then read the result.