Which personnel should be informed as part of the procedure when a tool is found missing?

The correct choice emphasizes the importance of communication and safety procedures in aviation maintenance. When a tool is found missing, it's crucial to inform specific personnel who are directly involved with the aircraft's operational and maintenance integrity.

The Flight Deck Coordinator (FDC), Maintenance Control, and Quality Assurance (QA) teams are key personnel who need to be notified because they have the responsibility and authority to assess the impact of the missing tool on the aircraft’s airworthiness and operational readiness. The involvement of these teams ensures that a thorough investigation can be conducted, and necessary measures can be taken to locate the tool or mitigate any potential risk it may pose. This process is essential to maintaining safe operating conditions and preventing incidents that could arise from tool-related failures.

In contrast, notifying only the pilot and co-pilot does not encompass the full scope of responsibility for ensuring the safety and aircraft integrity, while involving all flight crew may lead to unnecessary alarm without appropriate context. Dismissing the issue as minor could undermine safety protocols, leading to serious risks. Therefore, communicating with FDC, Maintenance Control, and QA aligns with best practices in aviation safety and operational protocols.