How must an aircraft return to service after maintenance that has altered its flight characteristics?

When an aircraft undergoes maintenance that alters its flight characteristics, it is essential to ensure that the aircraft operates safely and efficiently under its modified condition. This process typically involves an operational check performed by a rated pilot. The pilot assesses the aircraft's performance to confirm that it meets the necessary safety standards and operates within the specified parameters.

The operational check is critical because it involves actual flight conditions, allowing the pilot to evaluate how the aircraft responds to control inputs and how it behaves in various flight configurations. This check is especially important when the alterations could affect the control surfaces, weight distribution, or other significant aspects of the aircraft's flight dynamics.

Logging the flight check is beneficial but does not alone ensure that the aircraft is fully ready for service following such maintenance. While completing a maintenance report is also part of the process, it does not replace the need for an operational evaluation. A certification from the manufacturer, while potentially relevant for some maintenance aspects, is not always necessary for all alterations and does not assure that the aircraft has been adequately tested in real-world conditions.