Which of the following events can typically be covered by maintenance reserves?

Maintenance reserves are typically used to cover significant scheduled maintenance activities that involve substantial costs and resources. Among the options provided, airframe heavy maintenance and engine performance restoration clearly fall into this category.

Heavy maintenance refers to comprehensive inspections and refurbishments that may occur on aircraft structures or systems after a certain number of flight hours or cycles, which are critical for ensuring long-term safety and performance. Engine performance restoration entails overhauls that are essential for retaining engine efficiency and reliability over time. These activities often require meticulous planning, specialized labor, and significant financial investment, which aligns with the purpose of maintenance reserves.

In contrast, while routine inspections, emergency repairs, and daily checks are essential aspects of aircraft maintenance, they are generally considered operational and ongoing expenses rather than major scheduled events for which reserves are set aside. They might not incur enough costs to justify drawing from maintenance reserves, which are specifically allocated for more extensive and costly interventions needed to maintain aircraft airworthiness and performance.