What is an operator's responsibility regarding aircraft maintenance?

An operator's responsibility regarding aircraft maintenance is fundamentally about ensuring that all maintenance activities comply with established regulations. This includes adhering to the standards set forth by aviation authorities, such as the FAA or EASA, which outline the procedures, record-keeping, and oversight required to maintain an aircraft's airworthiness.

By ensuring that maintenance is performed according to these regulations, the operator is actively contributing to the safety of the aircraft, its passengers, and crew. This responsibility encompasses not only routine inspections but also the maintenance and repair of systems when necessary, thereby upholding airworthiness and safety standards throughout the aircraft's operational life.

In contrast, the other options do not adequately represent the comprehensive nature of an operator's responsibilities. Completing maintenance only when deemed necessary can create gaps in safety; hiring external contractors might not ensure compliance unless they are also adhering to the same regulations; and reporting only major faults overlooks the importance of routine checks and minor issues that can escalate if not addressed. Thus, the correct answer emphasizes the operator's role in regulatory compliance as the cornerstone of responsible aircraft maintenance.