When are common hardware items authorized to be in the composite tool kit (CTK)?

The correct choice reflects the understanding that common hardware items are authorized to be included in the composite tool kit (CTK) when they are necessary for specific tasks and operations as tools. This means that these items serve a functional purpose related to the maintenance and operation of aircrew flight equipment. The rationale behind this provision is to ensure that personnel have immediate access to the necessary aids to perform their duties effectively and maintain equipment as needed.

Having common hardware items available whenever they are required helps in streamlining maintenance processes and reduces downtime since it allows aircrew members to quickly address any issues that arise. It emphasizes preparedness and operational efficiency, ensuring that the tools needed are on hand when necessary for repairs or adjustments.

In the context of the other options, authorization does not solely depend on whether items are currently in use or exclusively needed during maintenance activities. Similarly, being specially marked does not inherently dictate whether they should be part of the CTK; instead, relevance to the task at hand drives the inclusion of these items in the kit.