Legal Framework and International Conventions
The treaty architecture
The legal framework has three layers: international conventions, ICAO standards and recommended practices (the Annexes to the Chicago Convention, notably Annex 17 on security), and national law implementing them.
The Chicago Convention (1944) established ICAO and the principle that states regulate civil aviation. The Tokyo Convention (1963) addresses offences and certain acts committed on board and the powers of the aircraft commander. The Hague Convention (1970) deals with unlawful seizure of aircraft (hijacking). The Montreal Convention (1971) covers other acts of violence against civil aviation, such as sabotage and attacks on airports. The Montreal Protocol (1988) extended the framework to acts of violence at airports serving international civil aviation. Later instruments, including the Beijing Convention and Protocol (2010), modernised the framework for new threats.
A second family of instruments governs liability and compensation, and a third governs facilitation and handling of passengers. Do not confuse the security conventions with the liability conventions; exam distractors frequently swap them.
Jurisdiction and obligations
The core obligation on states is to prevent the departure of aircraft and persons where there is reason to believe an act of unlawful interference is planned, and to ensure that security measures are applied to flights. Carriers and airport operators receive obligations through national law.
Traps and a worked example
A typical trap: a question describes an aircraft commander restraining a disruptive passenger and asks which convention applies. The commander's powers derive from the Tokyo Convention, not Hague or Montreal. If the question instead describes a hijacking, the answer is Hague; sabotage or an attack on airport facilities, Montreal.
Rule of thumb: match the act to the instrument: on-board offences and commander's powers = Tokyo; seizure of the aircraft = Hague; other violence against aviation = Montreal.