When must an ATC transponder be tested and inspected to comply with regulations?

An ATC transponder must be tested and inspected within the preceding 24 calendar months to comply with regulatory requirements. This timeframe is established to ensure that transponders, which play a crucial role in air traffic control and enhancing the safety of navigation, are functioning correctly. Regular testing and inspections help to identify any potential malfunctions or degradation in performance, which can affect situational awareness and operational safety. Adhering to this 24-month schedule is critical for maintaining regulatory compliance and ensuring the reliability of aircraft equipment necessary for safe flight operations.