What type of maintenance inspection does NOT require a 100-hour inspection?

Progressive maintenance is a type of inspection that is conducted on a continual basis rather than adhering to the strict timelines set by a 100-hour inspection. This approach allows for scheduled maintenance to be performed incrementally, often focusing on specific components or systems at different intervals. Because the progressive maintenance system is designed to distribute inspections and repairs over time, it does not require a 100-hour, which is a specific inspection mandated for specific operational situations, particularly for aircraft used for hire.

In contrast, an annual inspection is mandated every 12 months for all aircraft, regardless of usage. VOR inspections are required every 30 days for aircraft flying under IFR when using VOR navigation, and transponder checks must be performed every 24 months to ensure compliance with regulations for airworthiness and functionality. Therefore, the nature of progressive maintenance allows it to operate outside the usual frequency of more time-bound inspections like the 100-hour check.