Which of the following could be considered a major aviation security contingency?

A disruptive passenger represents a major aviation security contingency because it poses a direct threat to the safety and security of the aircraft, its passengers, and crew. Such individuals can create chaos onboard by instigating conflicts, demonstrating aggressive behavior, or even attempting to breach security protocols. The presence of a disruptive passenger can necessitate immediate action from flight crew members, including potential emergency landings and interventions by law enforcement upon arrival.

In contrast, while bad weather, flight delays, and mechanical failures can significantly impact airline operations and passenger experiences, they are not primarily categorized as security contingencies. Weather conditions might lead to cancellations or rerouting, and mechanical failures can affect the safety of the flight but are not directly linked to human threats or intentional acts against aviation security. Disruptive passengers, however, require specialized training and protocols to manage effectively, emphasizing their classification as a critical security concern in aviation.