What does a "multimeter" do in aircraft maintenance?

A multimeter is an essential tool in aircraft maintenance, primarily used for diagnosing and troubleshooting electrical systems. Its capability to measure voltage, current, and resistance makes it invaluable for technicians working with the various electrical components and circuits found in aircraft.

By measuring voltage, the multimeter can help determine if a circuit is functioning correctly or if there are issues like shorts or open circuits. It can also assess current flow, which is critical for understanding if an electrical component is drawing the correct amount of power. Additionally, measuring resistance is crucial for checking the integrity of wiring and connections; high resistance can indicate faulty components or corroded connections that may lead to operational failures.

The other choices relate to different measurements that are not the primary function of a multimeter. Measuring fuel flow and pressure, altitude and airspeed, or temperature and humidity requires specialized instruments tailored for those specific parameters. Hence, the role of the multimeter is uniquely focused on electrical measurements, which is foundational for effective aircraft maintenance and safety.