With respect to unlawful interference, which statement is correct?

• A. Each State shall ensure that aircraft unlawfully seized which have landed in their country are detained and not allowed to leave under any circumstances.
• B. As Annex 17 does not adequately cover it, the States concerned should communicate between each other when a hijacking occurs.
• C. Each State shall not provide any air traffic services and navigation aids to aircraft that are unlawfully seized.
• D. Each State shall ensure that aircraft unlawfully seized which have landed in their country are detained on the ground unless the overriding factor is to protect passengers' lives.

Answer: (D)

Unlawful interference scenarios, like hijackings, are handled by a principle that prioritizes safety and control once the aircraft lands. The correct approach is that a state should detain an unlawfully seized aircraft on the ground to keep the situation secure and allow authorities to manage the incident. This detention is not absolute without regard to risk—there is an important life-safety exception: if continuing to detain the aircraft would endanger passengers, authorities may permit actions that depart from strict detention to protect lives.

This balances the need to prevent further harm with the practical realities of negotiating, rescuing passengers, and bringing the situation to a safe resolution. The other statements misstate the framework: detaining the aircraft indefinitely under all circumstances ignores life-safety considerations; Annex 17 does address unlawful interference and does not leave this issue unregulated; and denying air traffic services to the hijacked aircraft would undermine safety rather than support it.