Which of the following defines all aspects of maintenance?

The definition of maintenance encompasses a comprehensive set of actions intended to preserve the functionality, safety, and longevity of an aircraft. The correct choice includes overhaul, repair, parts replacement, inspection, and preservation, which collectively encompass all critical aspects of maintenance.

Overhaul refers to the extensive restoration of equipment to ensure it meets safety and operational standards, while repair deals with fixing specific issues that arise during operation. Parts replacement involves substituting components that are worn or damaged to maintain the integrity of the aircraft. Inspection is vital for identifying potential problems before they lead to failures, ensuring safety and compliance with regulations. Preservation includes activities aimed at protecting the aircraft from deterioration due to environmental factors.

This choice fully integrates all necessary actions that fall within the maintenance category, ensuring that all potential areas for upkeep and safety are addressed.