Tension over East China Sea Adiz

“ADIZ” HAS only lately gained prominence in Philippine vocabulary. It stands for “air defense identification zone.” It means an area of airspace over land or water in which the identification, location and control of civil aircraft are required by the state claiming control over the airspace. Interestingly, the authority to establish an Adiz is not governed by international law. Nor does any international body exist to regulate it. Much of what I have to say I have gathered from unofficial sources.

In international law the sovereignty of a state extends over its land area and waters as well as over its airspace (usque ad caelum). The limits on land area are fairly set, and so is the law of the sea. Air law and space law, however, are of more recent development.

An early view was that airspace was entirely free; another view is that there is a territorial airspace analogous with the territorial sea; still another is that all the airspace above a state is within its sovereignty, and still another view posited a right of innocent passage through the airspace for foreign civil aircraft. However, World War II altered things. There came the realization that airspace had security implications. Hence the birth of Adiz. (The developments in the exploration of outer space are for the moment the concern only of states which can afford to go to outer space. We are far from that even though a Filipino going to outer space has been identified.)

The first Adiz was established unilaterally by the United States shortly after World War II. It requires that “[a]ny aircraft that wishes to fly in or through the boundary must file either a Defense Visual Flight Rules (DVFR) flight plan or an Instrument Flight Rules (IFR) flight plan before crossing the Adiz.” The reason cited for the establishment of the Adiz is “the legal right of a nation to establish reasonable conditions of entry into its territory,” the same reason China has cited. There are now four US air defense identification zones: the Contiguous US Adiz; the Alaska Adiz; the Guam Adiz; and the Hawaii Adiz. If radio interrogation fails to identify an aircraft in any of these zones, the US Air Force is to launch interceptor aircraft to identify the intruder visually.

Canada, Korea and Japan also maintain air defense identification zones. What in recent months has caused tension is the Adiz set up by China on Nov. 23, 2013, over the East China Sea.

The East China Sea Adiz rules require aircraft flying in the zone to provide flight plan identification, radio identification, transponder identification and logo identification. Aircraft flying in this Adiz must clearly mark their nationalities and the logo of their registration identification in accordance with related international treaties. Finally, China’s armed forces, in the exercise of the rights of sovereignty, will adopt defensive emergency measures to respond to aircraft that do not cooperate in the identification or refuse to follow instructions.

Expectedly, the United States has criticized China for setting up the East China Sea Adiz unilaterally. But this alone should not be a basis for criticism because the United States has also established similar zones unilaterally. The more serious point of contention comes from the more exacting rules of the East China Sea Adiz as compared with those of the US Adiz. Thus, US Vice President Joe Biden has publicly and emphatically announced that the United States will not honor the East China Sea Adiz. And China seems to be having second thoughts about implementing its East China Sea Adiz.

So far there has been no reported Chinese reaction to a violation, if any, of the East China Sea Adiz.

As far as the Philippines is concerned, President Aquino has said that he is not bothered by the East China Sea Adiz. I think he will be bothered by the recent report that China is also establishing an Adiz over the West China Sea which we consider Philippine Sea.