When is a 100-hour inspection required?

The requirement for a 100-hour inspection is specifically tied to the operations of the aircraft, particularly concerning the carriage of passengers for hire or flight instruction. According to FAA regulations, a 100-hour inspection is mandatory for aircraft that are used for hire (including flight instruction) when they have accumulated 100 hours of flight time since the last inspection. This regulation ensures that aircraft used in commercial operations are maintained to a higher standard of safety and reliability, as they are carrying passengers and potentially being used in higher-risk environments.

The other scenarios presented, such as simply accumulating 100 hours of flight time regardless of the operational context, crossing state lines, or timing related to annual inspections, do not trigger the 100-hour inspection requirement. The inspection is strictly linked to the use of the aircraft for compensated operations, underscoring the focus on safety for those business-related flight activities.