An ADIZ with Chinese Characteristics


While China’s unilateral declaration of an air defense identification zone (ADIZ) over disputed waters in the East China Sea (ECS) caught many by surprise, today’s debate circles around the likelihood that Beijing might take the same action over the South China Sea (SCS). In its pursuit of maritime primacy in Northeast Asia, China has strayed far from the international norms that dictate the implementation and use of an ADIZ.

An ADIZ is an airspace beyond a country’s sovereign territory within which the state requires the identification, location, and air traffic control of aircraft in the interests of national security. The mechanism is a legacy of the Cold War, having first been declared by the U.S. in 1950. More than 20 states now administer their own ADIZ.

According to the Chinese Ministry of National Defense, when entering the zone, such as the one declared over the ECS, all aircraft are required to identify themselves, report flight plans, and inform ground control of their exact position. Such regulations apply to commercial aircraft as well as military aircraft. On the latter count, China’s ADIZ fails to uphold the normative principle that military aircraft simply transiting through an ADIZ shouldn’t be obliged to report to the host country. China has threatened to meet non-compliance with “military defensive measures.” The U.S. State Department was highly critical of the coercive measure, claiming that “the U.S. does not apply its ADIZ procedures to foreign aircraft not intending to enter the U.S. national airspace.” The State Department urged China “not to implement its threat to take actions against aircraft that do not identify themselves or obey orders from Beijing.”

China’s reinterpretation of how an ADIZ is declared and operates raises questions about the legality, legitimacy and intentions of its controversial efforts over the ECS. ADIZs are legally ambiguous, and aren’t regulated by any defined international regime. Although there’s no explicit prohibition on ADIZs, they can be used in ways that violate other international legal provisions. China’s specific identification requirements placed on military aircraft are in violation of Article 87 of the United Nations Convention of the Law of the Sea (UNCLOS), which protects “freedom of overflight” and to which China is a signatory. The 1944 Convention on International Civil Aviation – the Chicago Convention – also rules against unilateral attempts to restrict air navigation beyond a state’s territorial seas. Therein lies the danger: China’s attempt to maintain de-facto control of its surrounding waters will contribute to establishing a precedent outside of current international law.

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