What is the normal inspection period for a transponder under CAR 91?

The normal inspection period for a transponder under Civil Aviation Rules (CAR) 91 is indeed 24 months. This requirement ensures that transponders, which are critical for aircraft identification and safety, maintain their functionality and accuracy. Regular inspections help ensure that the equipment is operating correctly and in compliance with safety standards.

Transponder inspections are vital not just for the individual aircraft's operational capability but also for the overall safety of the airspace system. A transponder that fails to work properly can lead to difficulties in air traffic control identifying and tracking an aircraft, which can create unsafe situations.

The longer inspection periods, such as 36 or 48 months, are not standard for transponders, as the risk of malfunction or degradation in performance increases over time without regular checks. Regular two-year inspection intervals help mitigate these risks, ensuring both the equipment reliability and compliance with regulations.