Threat level 4 corresponds to what behavior?

• A. Disruptive behavior - Suspicious or Threatening
• B. Armed individual
• C. Attempted or actual breach of the flight deck
• D. Life threatening behavior

Answer: (C)

In-flight security threat levels are tied to the severity and nature of the incident. Level four is defined by a situation involving an attempted or actual breach of the flight deck, which is the most serious cockpit-security event and calls for immediate, decisive action by crew and authorities. This specific scenario directly indicates a breach of the protected cockpit area, signaling the highest level of threat and prompting rapid protective measures. Other described behaviors describe dangerous conduct, but they do not involve a breach of the flight deck, so they do not fit level four in this framework.