Which investigation involves potential civil aircraft or FAA personnel?

The interagency investigation is the correct choice as it pertains to incidents that involve multiple agencies, including civil aircraft operations and potentially FAA personnel. This type of investigation typically engages various federal and state organizations, and when civil aircraft are involved, the FAA plays a critical role in ensuring safety and compliance with aviation regulations. Interagency collaboration is essential in these investigations to gather comprehensive data, analyze the circumstances surrounding an event, and develop necessary safety recommendations or regulatory changes.

In contrast, other types of investigations mentioned, such as field naval aviator evaluations, aviation mishap safety investigations, and class D mishap investigations, generally focus more narrowly on military operations or specific mishap evaluations rather than a broader context that includes civil aircraft or FAA oversight. They may not involve the same level of collaboration between FAA and civil aviation entities, which is a key aspect of interagency investigations. This distinction highlights the unique nature of interagency investigations in addressing issues that directly impact civilian aviation and regulatory oversight.