Are aircraft inspections based on airtime or flight time?

Inspections for aircraft are primarily based on airtime, which refers to the time the aircraft is in flight with the wheels off the ground. This method of tracking is essential because it relates directly to the wear and tear experienced by various components of the aircraft during flight. Maintaining the aircraft’s airworthiness is paramount, and the impacts of flight, such as mechanical stress and operational conditions, are most accurately reflected in the airtime accrued.

Flight time, while a common term used, typically encompasses the entire duration from when the aircraft begins the takeoff roll until it comes to a stop after landing, including ground maneuvering. However, regulations and maintenance schedules focus explicitly on airtime since it better correlates with the aircraft's actual operational state during flight.

While other considerations such as distance traveled and type of operation do play roles in certain maintenance schedules and inspections, they are not the primary metrics used for regular aircraft inspections. Consequently, understanding that inspections are based on airtime emphasizes the significance of the in-flight operational aspects of aircraft maintenance and safety.