What is defined as "preventive maintenance"?

The correct answer is the replacement of small standard parts without complex assembly. Preventive maintenance refers to routine activities that are performed to maintain the craft in a condition of compliance with established safety standards. This includes tasks that do not require technical expertise or extensive knowledge of the system, thus allowing pilots to undertake simpler maintenance duties themselves.

Preventive maintenance can encompass actions such as checking fluids, replacing filters, and changing spark plugs, which are tasks that are straightforward and do not involve complicated disassembly of systems or components. This aspect of preventive maintenance is critical for ensuring the ongoing airworthiness of the aircraft without necessitating the direct involvement of certified mechanics for every minor issue.

Other options describe either restrictive or broader categories of maintenance that don't align with this specific definition. For instance, complex assembly operations would typically not fall under preventive maintenance because they require advanced skills and knowledge. Similarly, minor repairs performed by manufacturers suggest assistance beyond what a pilot is authorized to do, and defining maintenance tasks broadly as all except inspections extends beyond the scope of preventive maintenance, which focuses specifically on small tasks that preserve functionality.