Private Pilot Private Exam

Which of the following statements about electrical systems is true?

1. The master switch provides current to the electrical system

2. The airspeed indicator operates independently of the electrical system

3. Lights and radios utilize the electrical system for their power

4. The fuel pump system does not require electrical power

The correct answer is: Lights and radios utilize the electrical system for their power

The statement regarding lights and radios utilizing the electrical system for their power is accurate because these components are designed to operate by drawing electrical energy from the aircraft's electrical system. In general aviation aircraft, the electrical system is responsible for powering various systems that are critical for safe operation, including lighting for visibility and communication equipment. The master switch plays a role in controlling the flow of electrical current to the system but does not provide current on its own; it simply connects or disconnects the battery and alternator from the electrical bus. The airspeed indicator, on the other hand, is typically a mechanical instrument that relies on air pressure rather than electrical power, and while certain fuel pump systems may operate independently, most modern aircraft utilize electrically powered fuel pumps. Thus, the reliance of lights and radios on the electrical system is a fundamental aspect of how these components function in aeronautics.