How often should aircraft instruments be checked and calibrated?

The maintenance of aircraft instruments is crucial to ensure safety and reliability during flight. The correct response emphasizes the importance of adhering to the aircraft's maintenance schedule, which is established by the manufacturer and regulatory authorities. This schedule includes specific intervals for checking and calibrating instruments, taking into account factors like operating conditions, flight hours, and the specific instruments involved.

Regular calibration and checks according to the recommended schedule help in identifying any drift in instrument accuracy, preventing potential discrepancies that could lead to unsafe flight situations. By following these guidelines, pilots and maintenance personnel can ensure that all instruments are functioning within specified parameters, thereby enhancing the overall safety and performance of the aircraft.

The other options suggest infrequent checks or less rigorous approaches, which could lead to the risk of instrument errors going unnoticed. Annual checks alone do not account for wear and tear or operational changes that may affect instrument accuracy, while routine pre-flight checks, while critical, may not be comprehensive enough to address calibration needs. Lastly, waiting until an aircraft reports incorrect readings could result in unsafe conditions, as the need for calibration should be proactive rather than reactive.