How is "time-in-service" defined in relation to maintenance record entries?

"Time-in-service" is defined as the duration that an aircraft is in operation, specifically from the point it leaves the ground until it lands at the next point. This measure is important for maintenance tracking and compliance with maintenance schedules, as it informs technicians about the operational history of the aircraft, aiding in determining when inspections, maintenance, or repairs are needed based on flight hours.

In the aviation maintenance context, focusing on when an aircraft is airborne provides a more accurate measure of usage for maintenance purposes. This aligns with regulatory requirements and industry standards that help ensure safety and efficiency.

The other statements describe timeframes that do not encompass the full definition of "time-in-service" as required for maintenance records. For instance, defining it only from takeoff until cruising altitude or just from engine start to shutdown does not capture the entire flight duration, which is crucial for tracking operating limits and maintenance schedules effectively.