Aircraft Fuel Systems Practice Exam 2026 - Free Aircraft Fuel Systems Practice Questions and Study Guide

Capacitance fuel quantity indicators are designed to measure the level of fuel in a tank by detecting the capacitance change as the fuel level varies. Proper calibration of these indicators is essential for accurate readings. When calibration is off, several types of errors can occur.

Under-reporting of fuel levels happens when the system inaccurately indicates a lower fuel amount than what is actually present. This could result from calibration settings that do not account for the specific dielectric constant of the fuel.

Conversely, over-reporting can occur if the system is set to a calibration that incorrectly interprets capacitance signals, giving the impression that there is more fuel in the tank than is truly the case.

Temperature changes can also influence capacitance measurements, as the dielectric constant of fuel varies with temperature. Without proper calibration, the indicators might read inaccurately due to variations in temperature, causing erroneous readings.

Therefore, poor calibration can lead to all these issues – under-reporting, over-reporting, and erroneous readings due to temperature fluctuations. This justifies why the correct answer encompasses all of these potential errors.