During a storm, the city's 911 CAD system goes down even though no records were stolen. Which CIA objective was primarily violated?

Availability ensures authorized users can access systems and data when needed with acceptable reliability and timeliness. When the city's 911 computer-aided dispatch (CAD) system goes down during a storm—even though no records were stolen—the primary CIA objective violated is availability: dispatchers and responders who should use the system cannot obtain timely, reliable access to a required public-safety capability.

Choosing confidentiality because "outages always imply data disclosure" is incorrect; downtime does not by itself mean information was exposed. Choosing integrity because "downtime automatically corrupts databases" invents a modification failure that the stem does not describe—systems can be unavailable while data remains unchanged and trustworthy. Choosing non-repudiation because callers "cannot deny dialing 911" misapplies a concept about binding actors to actions; call repudiation is not the failure mode when CAD is dark.

Exam caveat: Security+ emphasizes that CIA elements are independent. A pure availability incident needs no breach narrative. Public-safety and municipal critical systems make availability failures especially visible because lives and services depend on uptime, but the definition remains the same across sectors.

Operational check: treat CAD and related 911 infrastructure as high-availability civic systems—redundant power and network paths, tested failover, documented manual dispatch fallback, and monitoring that pages before citizens notice. After storms, review whether availability controls (UPS, generators, diverse circuits, vendor SLAs) matched the risk, independent of confidentiality tooling.