According to reports, the Pentagon on Wednesday released a statement accusing China of conducting "unsafe" interception of a US spy plane in "international airspace" over the South China Sea. This accusation immediately reminds me of the 2001 EP-3 collision incident between China and US, which led to the death of a Chinese pilot. Both incidents involve the US EP-3 spy plane conducting intelligence-gathering activities in the same place of South China Sea.

This raises concern about the possibility of another looming in the airspace over the South China Sea, and as well a question of who would be to blame. The answer may necessitate a full analysis of the lawfulness of the US reconnaissance activities in the airspace over foreign Exclusive Economic Zones (EEZs).

Under the 1982 United Nations Convention on the Law of the Sea (UNCLOS), the world oceans are divided into various jurisdictional zones, where different legal regimes with balanced rights and duties between coastal and user states applies respectively. These legal regimes applied in various jurisdictional zones serve as a benchmark for deciding on the lawfulness of the conduct of relevant parties. Consequently, the place where the incident happened plays a key role in judging the lawfulness of the US reconnaissance activities.

The US has as always claimed that the interception took place in international airspace over the South China Sea, a term that could be found nowhere in the UNCLOS. Based on the US stance as reflected in its public statement and Navy Commander's Operational Handbook, the term "international space" refers to the airspace over the maritime areas beyond territorial waters, which may include airspace over both the EEZs and the High Seas. This is a typical American understanding of the international law of the sea, which purports to name each maritime area and its above airspace with its exact name as stipulated under the UNCLOS, such as the territorial sea, the EEZ, the High Seas, etc.

Notwithstanding the fact that the US is not a party to the UNCLOS but habitually uses some articles of UNCLOS to its advantage, the US-designed term does lead to a serious conflict of understanding of law regarding the legal status of each maritime area and its airspace, in particular within EEZs.

While the international community aligned under UNCLOS takes the EEZ as a particular maritime zone regulated under a specific legal regime with balanced rights and obligations between the user and coastal states, the US, as a non-party to UNCLOS, insists that the freedom of navigation and overflights exercised within and beyond EEZs "must be qualitatively and quantitatively the same as the traditional high seas freedoms recognized by international law." Consequently, this different understanding of law may well lead to operational confrontations at sea.

Another element that may have a bearing on the analysis of lawfulness of the US reconnaissance activities is the rules of international law regarding un-alerted air encounters between military aircrafts. The 1944 Chicago Convention on International Civil Aviation, to which both China and US are parties, does have an Annex 2 entitled Rules of the Air, which recommends standards and best practice with regard to the interception of civilian aircrafts, but it does not apply to the interception of state aircraft, military aircraft included.

We could also cite the China-US MOU on Air and Maritime Encounters as a benchmark. Notwithstanding the non-binding force of the nature of the MOU, this also raises the question of who would be the judge to decide on lawfulness of the said encounter.

While the Pentagon Wednesday "praised" Chinese pilots as "flying in a safe and professional manner" over past years, the US should spend more time to review whether the US pilots are flying in a safe and professional manner in either the South China Sea or the Baltic Sea, or in any part of the world.

History repeats itself if its lessons are not learned. And now it is time for the US to review its conduct so as not to make the same mistake in the same place. It is also time for the international community to choose between a hegemonic ocean legal order based on the US interpretation of international law and a world ocean legal order under UNCLOS.

The author is a research fellow with the Collaborative Innovation Center of South China Sea Studies. opinion@globaltimes.com.cn