What type of indicator must electric gyro instruments have?

Electric gyro instruments must have a failure indicator to ensure operational reliability and safety in aviation. The failure indicator serves a crucial role by alerting the flight crew to any malfunctions or discrepancies in the gyro mechanism. Since these instruments are critical for navigation and control, having a failure indicator allows for immediate recognition of any issues, enabling timely corrective actions.

In the case of electric gyros, a failure could affect the accuracy of vital flight information, such as orientation and attitude. The presence of a failure indicator helps pilots maintain situational awareness and make informed decisions while flying. Other types of indicators, such as speed, altitude, or pressure indicators, serve different functions and do not specifically address the integrity of gyro-based instruments. This focus on monitoring for failures enhances overall flight safety by providing an additional layer of information regarding the operational state of the instruments.