Which of the following items is likely to be accessed using CASS?

CASS, or the Crew Access Security System, is specifically designed to facilitate secure access to the cockpit by managing information related to individuals who are authorized to enter this sensitive area of the aircraft. This includes verifying the identity and qualifications of crew members and personnel who require access to the cockpit during flight operations.

The personal data of individuals seeking cockpit access encompasses essential details that ensure security protocols are followed and allows for efficient verification of those individuals' credentials. This aligns with the primary function of CASS, which is to manage access based on the security requirements of aviation environments.

In contrast, flight safety manuals and passenger manifests do not pertain directly to access control for the cockpit, nor do crew member certifications typically require the same security measures as personal data for cockpit access. Thus, these options do not fit the specific context of CASS usage as accurately as personal data for individuals requiring cockpit access.