Do standby altimeter and airspeed indicators require electrical power?

• A. Yes
• B. No, they do not
• C. Only altimeter requires power
• D. Only airspeed indicator requires power

Answer: (B)

Standby altimeter and airspeed indicators are designed to function independently of the aircraft's electrical systems, which is a critical feature for maintaining safety and reliability. These instruments rely on mechanical or barometric methods to provide accurate readings of altitude and airspeed.

The standby altimeter typically uses a diaphragm that expands or contracts based on changes in atmospheric pressure, allowing it to indicate altitude without needing electrical inputs. Similarly, the airspeed indicator operates based on the principle of differential pressure between static and dynamic air pressures, allowing it to provide speed readings without electrical dependency.

This design ensures that even in the event of electrical failure or power loss in the aircraft, pilots will still have access to vital flight information from these standby instruments, enhancing the safety of flight operations. Therefore, the assertion that these instruments do not require electrical power is correct.