Freedom of Overflight as a Feature of International Straits in the LOSC

The LOSC has been described as a “package deal” and, in his historic address, Tommy Koh as president of the Third UN Conference on the Law of the Sea (UNCLOS III) reminded the participating delegations and other members of the international community of the importance of respecting the trade-offs and compromises achieved after nine years of arduous negotiations. ^{Footnote 13} Indeed, progress in certain areas of the law of the sea was only achieved once compromises had been brokered on other issues. The long-awaited rule on the maximum extent of the territorial sea was one such hard-won success. While there was considerable momentum in favour of enlarging the territorial sea to a maximum breadth of twelve nautical miles when UNCLOS III began in 1973, the prospect of an enlarged zone of sovereign control raised serious concerns in respect of other fundamental aspects of the law of the sea. Chief among them were the consequences an extended twelve-nautical-mile territorial sea would have for certain strategic international straits.

International straits have always been considered of vital importance to global maritime trade and naval mobility, often providing the only direct access from one ocean or sea to another. ^{Footnote 14} As long as the territorial sea was limited to a maximum breadth of three nautical miles, the most strategic straits around the world had within them a high seas corridor with a right of unfettered navigation and overflight for the ships and aircraft of all nations.

However, as proposals for the establishment of a twelve-nautical-mile territorial sea gained momentum during UNCLOS III, the principal maritime powers, with the United States leading the pack, expressed legitimate concerns over the negative impact such a development would have for the right of free transit through international straits. Such an expansion would result in approximately 100–120 straits becoming wholly enclosed within the territorial seas of the bordering states, ^{Footnote 15} including such maritime hotspots as the Straits of Gibraltar (eight nautical miles in breadth), Hormuz (twenty-one nautical miles in breadth), and Malacca (twenty-one nautical miles in breadth).

These three critical maritime arteries, along with others affected by the expansion of the territorial sea, are of vital importance to the international community. In terms of global seaborne oil transportation, the Strait of Hormuz, leading out of the Persian Gulf, and the Strait of Malacca, linking the Indian and Pacific Oceans, are the world’s most important strategic chokepoints. In 2013, seventeen million barrels of crude oil and petroleum products were transported through the Strait of Hormuz (about 30 percent of all seaborne-traded oil), while 15.2 million barrels were shipped through the Strait of Malacca. ^{Footnote 16} The US Energy Information Administration estimates that, on average, fourteen crude oil tankers per day passed through the Strait of Hormuz in 2011, with a corresponding number of empty tankers entering to pick up new cargo. ^{Footnote 17} According to the website of the Gibraltar Port Authority, over 71,000 vessels transit the Strait of Gibraltar every year, ^{Footnote 18} while data from Malaysia’s Marine Department’s STRAITREP reporting system indicates there were 72,657 transits of the Malacca Strait in 2014 by vessels of 300 gross tons or more. ^{Footnote 19} Unfortunately, no comparable statistics exist in terms of the number of aircraft flying over these strategic waterways.

Once these key straits were enclosed within the newly extended territorial seas of the bordering states, foreign ships would be subjected to the regime of innocent passage, a regime rightly considered to be much more restrictive than that applicable on the high seas, especially as the former was then defined under the 1958 Convention on the Territorial Sea and Contiguous Zone (1958 Convention). ^{Footnote 20} Article 14(4) of the 1958 Convention provided that passage was innocent so long as it was not prejudicial to the peace, good order, and security of the coastal state. However, only a single, objectively identifiable act was identified as liable to deprive passage of its innocent character — fishing:

Thus, the determination of what activities or behaviour might or might not be considered prejudicial to the interests of the coastal state was essentially left to the subjective evaluation of the interested state. Maritime powers, therefore, protested against an outcome that would subject navigation through international straits to the unfettered discretion and potentially arbitrary whims of bordering states. ^{Footnote 21}

Other aspects of the regime of innocent passage were also deemed incompatible with the vital interests of the international maritime community in regard to international straits. Under the regime of innocent passage, submarines would not be able to transit straits in their normal (submerged) mode of navigation but rather, would be compelled to navigate on the surface, ^{Footnote 22} a much less efficient mode of operation. ^{Footnote 23} During the second session of UNCLOS III in the summer of 1974, in a bid to convince other delegations of the need to recognize a right of submerged transit for submarines, the representative of the United States also insisted that “as submarines are designed to travel submerged, that is the safest way for them to pass through an international strait.” ^{Footnote 24}

Of even greater strategic significance, the unsatisfactory regime of innocent passage did not even apply to aircraft wishing to cross the narrower straits. Indeed, as defined in Article 14 of the 1958 Convention (and subsequently in Article 35 of the LOSC), and as established under customary international law, the regime of innocent passage applies only to ships. Thus, if the territorial sea were to be extended to twelve nautical miles, the airspace above straits such as the Straits of Gibraltar, Hormuz, or Malacca would be closed off to navigation by some type of aircraft in the absence of explicit permission from the underlying states. It is therefore not at all surprising that several delegations to UNCLOS III made their agreement on the expansion of the territorial sea out to twelve nautical miles contingent on the parallel creation of a regime of guaranteed freedom of navigation and also overflight through and above international straits:

As the UN Office for Ocean Affairs and the Law of the Sea explains, “the main aim of the maritime States was to preserve the right of unimpeded navigation and overflight which they had enjoyed in straits under the three-mile territorial sea rule. They supported a regime of ‘free transit’ which guaranteed strategic mobility and international trade and was analogous to the freedom of the high seas.” ^{Footnote 26} However, the proposed regime of free transit raised significant concerns for states bordering such straits, including the fear that the new regime would erode their national sovereignty and threaten their security as well as present significant risks for the safety of navigation and the marine environment. ^{Footnote 27}

The difficulty of arriving at a legal compromise that would ensure the protection of the international community’s interests in the freedoms of navigation and overflight while also guaranteeing coastal states’ territorial and environmental integrity was already very much in evidence during the initial sessions of the Seabed Committee as it struggled to define the agenda items to be considered by UNCLOS III. ^{Footnote 28} On 17 December 1970, the UN General Assembly (UNGA) by Resolution 2750 C (XXV) had decided to convene a conference on the law of the sea and had assigned the preparatory work to the Seabed Committee. ^{Footnote 29} In paragraph 6 of the Resolution, the UNGA had instructed the Committee to prepare draft articles on the agenda items to be considered by the conference, a task eventually divided among three subcommittees. It fell to Subcommittee II “to prepare a comprehensive list of subjects and issues relating to the law of the sea, including those concerning the regimes of the high seas, the continental shelf, the territorial sea (including the question of its breadth and the question of international straits) and contiguous zone, fishing and the conservation of living resources of the high seas (including the question of the preferential rights of coastal States) and to prepare draft treaty articles thereon.” ^{Footnote 30}

A number of proposals were therefore already circulating during the preparatory phase of UNCLOS III, and they inevitably reflected the particular bias or strategic interest of the proposing nation. For example, during the second session of 1972, the representative of China declared that every coastal state in the world “had the right to define the extent of its territorial sea and to exercise its sovereign rights therein. Consequently, straits lying within the territorial waters of a coastal State still came under the national sovereignty of that State, even if they were often used for international navigation. Permitting innocent passage was not at all the same thing as closing the straits.” ^{Footnote 31} Responding to the Chinese and other statements, the representative of the United States reiterated that his country recognized a three-mile limit for the territorial sea and that, as a result, US flag ships and aircraft enjoyed high seas freedoms in straits more than six miles wide: “Consequently, an extension of the territorial sea to 12 miles would change the status of certain areas, including parts of certain international straits. The United States was prepared to accept such a result if the future treaty on the law of the sea preserved, with respect to international straits, free transit for all ships and aircraft.” ^{Footnote 32} This objective was identified as a basic element of the United States’ maritime policy “and could not be sacrificed.” ^{Footnote 33}

One of the aspects that was emphasized by a number of the participating delegates, whether they were from maritime or coastal states, was that the balancing exercise to be undertaken concerned only those international straits of importance and use to the community of nations. For instance, during the 1971 sessions of the Seabed Committee, the representative of the Soviet Union, in referring to the approximately 100 straits that would be affected by an expansion of the territorial sea, pointed out that in regard to many of those straits, “there had evolved over the centuries the practice — which could now be regarded as a legal norm — whereby the vessels of all countries had freedom of passage.” ^{Footnote 34} He added that for this reason “his delegation considered that there should be a distinct category of international straits … which had over a considerable period of history served as international waterways for international shipping.” ^{Footnote 35} In a follow-up statement, the Russian representative insisted that “only the main straits, which played an important part in international navigation, should, however, be considered, and a list of such straits should be drawn up.” ^{Footnote 36}

The representative for Czechoslovakia during the same session expressed his country’s deep concern with “safeguarding the freedom of navigation in international straits for vessels of all flags.” ^{Footnote 37} He considered it “inadmissible that certain States should extend their authority over important international straits which for centuries had been open to all.” ^{Footnote 38} The Australian representative, relying on Erik Bruël’s seminal work, ^{Footnote 39} commented that “the straits that enjoyed a legal position sui generis so far as passage was concerned were those that had a sufficient degree of importance to international sea commerce, taken in the sense covering both mercantile ships and warships.” ^{Footnote 40} The representative from Ethiopia, in advocating a cautious approach before special treatment could be established for international straits, referred to “straits traditionally used for international navigation,” ^{Footnote 41} while the representative from Singapore observed that his country attached great importance to navigation “through international straits which had for centuries past been used as part of the high seas.” ^{Footnote 42}

By the 1972 sessions of the Seabed Committee, as further additional proposals were submitted by the various delegations to Subcommittee II concerning the list of subjects to be considered by UNCLOS III, the formula “straits used for international navigation” had begun to dominate the discussions. It was included in the list of subjects and issues sponsored by fifty-six states ^{Footnote 43} and in the amendments proposed by the United States, ^{Footnote 44} the Soviet Union, ^{Footnote 45} France, the Netherlands, the United Kingdom, ^{Footnote 46} and Poland. ^{Footnote 47} During the ensuing discussions, the representative of the United Kingdom insisted that a new definition of an international strait was not required. Useful guidance, he said, could be found in the judgment of the International Court of Justice in the Corfu Channel case: ^{Footnote 48} “The Court had held that the decisive criterion was the geographical situation of the Channel as connecting two parts of the high seas and the fact that it was used for international navigation. There were few situations in the world where that decisive criterion would be difficult to apply.” ^{Footnote 49} However, some delegations continued to press for a more precise definition of those international straits that would be subjected to any newly defined transit regime, including, for example, the delegations from Turkey, ^{Footnote 50} Chile, ^{Footnote 51} Canada, ^{Footnote 52} Norway, ^{Footnote 53} France, ^{Footnote 54} and Peru. ^{Footnote 55}

When UNCLOS III was at last convened in 1973, the Conference decided to establish three main committees to deal with the subjects covered by the three subcommittees of the Seabed Committee. The question of straits used for international navigation was thus allocated to the Second Committee of the Conference. The first session of UNCLOS III was devoted to organizational matters but, during the second session (20 June to 29 August 1974), delegations were afforded new opportunities to comment on the question of straits and to submit draft articles. Among the most influential of these drafts were the draft articles submitted by the United Kingdom, which provided for a right of transit passage for all ships and aircraft in straits “used for international navigation.” ^{Footnote 56} Other delegations, however, through their own draft articles, continued to insist upon the need to qualify the level of international usage of a given strait: “[S]traits over which the airspace is traditionally used for transit flights by foreign aircraft”; ^{Footnote 57} “straits which are traditionally used for international navigation”; ^{Footnote 58} “straits used for international navigation means any strait … customarily used for international navigation”; ^{Footnote 59} “straits which … are customarily used for international navigation”; ^{Footnote 60} “an international strait is a natural passage between land formations which … has traditionally been used for international navigation”. ^{Footnote 61}

At the start of the third session in April 1975, the Second Committee decided to establish a number of informal consultative groups in which all members of the Committee could participate. The negotiating process in the Informal Consultative Group on Straits was greatly influenced by the work of the Private Working Group on Straits Used for International Navigation, which was also known as the Fiji/UK Group, ^{Footnote 62} which submitted at the very outset a consensus text on passage through straits used for international navigation. ^{Footnote 63} The Fiji/UK draft articles were favourably received by most of the members of the Consultative Group, who believed that a fair balance had been struck that could serve as a basis for negotiation. Indeed, as the UN Division for Ocean Affairs and the Law of the Sea comments, the proposal of the Fiji/UK Group “was to provide the basis for a compromise text ... That compromise text, with some minor amendments, evolved into what is now Part III of the Convention.” ^{Footnote 64}

One of the very few amendments subsequently made to the Fiji/UK draft articles was at the behest of Canada, Chile and Norway, which pointed out in an aide-mémoire dated 30 April 1975, that the rules defined in the Corfu Channel case and Article 16(4) of the 1958 Convention applied only to those straits “that lie within the territorial sea of one or more States.” ^{Footnote 65} These concerns were taken into consideration in the preparation of the informal single negotiating text relating to straits with the addition of draft Article 35, which stipulated that nothing in the part on “Straits Used for International Navigation” affected: “(a) Any areas of internal waters within a strait, unless they were considered as part of the high seas or territorial sea prior to the drawing of straight baselines.” ^{Footnote 66} This exclusion was eventually confirmed in Article 35 of Part III of the LOSC.

Throughout the various sessions of the Seabed Committee and the negotiating sessions of the Second Committee during UNCLOS III, a sharp divide existed between some delegations on the question of state vessels and aircraft. Indeed, while all of the delegations explicitly recognized the fundamental importance of reconciling the international community’s vital interest in mobility and world trade with the security and environmental integrity of states bordering straits, some delegations vehemently denied that this balancing exercise should take into account a right of free access for military ships and aircraft. For instance, during the 1971 session of the Seabed Committee, the Spanish representative opined that the only real justification for the proposed freedoms of navigation and overflight were strategic considerations:

During the same session, the representative of Malaysia declared that the superpowers “were clamouring for freedom of transit for their warships through territorial straits. Malaysia could not be expected to invite potential calamity by encouraging their war of nerves. In the present age, it was essential to ensure that the seas, the seabed and the ocean floor were used for peaceful purposes.” ^{Footnote 68} The representative of Greece was also of the opinion that the right of passage without discrimination would actually benefit only warships and military aircraft “which were the only ones for which the existing regime laid down restrictions. It could not be said that national peace and security would be strengthened as a result.” ^{Footnote 69} Similar comments were also made during the 1972 sessions of the Seabed Committee, including by the representative of China: “In demanding ‘freedom of transit’ and ‘freedom of overflight’ for foreign ships and aircraft, whether civilian or military, the super-Powers were seeking to treat territorial waters as the high seas, so as to ensure their maritime hegemony.” ^{Footnote 70} For his part, the representative from Tanzania noted that the right of free transit through straits appeared to be advocated by certain delegations for reasons totally unconnected with the facilitation of international navigation: “The proposal was aimed only at States with straits, and its result would be to subject some countries to military servitude.” ^{Footnote 71}

Some of the harshest criticisms of the right of transit passage for military ships and aircraft were voiced during the second session of UNCLOS III. According to the representative of Tanzania, warships were not in the service of the international community: “[R]ather, they were used to further the foreign policy objectives of a few States. Warships should therefore give notification of passage and should not pass through a strait secretly because of the risks to the coastal State.” ^{Footnote 72} The representative of Peru concurred with the views expressed by the Tanzanian delegation, insisting that a distinction had to be made between the interests of humanity in general and those of certain states: “The passage of merchant vessels through straits used for international navigation was a peaceful use of the seas, was considered innocent and was of benefit to all countries ... The passage of warships was not in the general interest, nor was it a peaceful and innocent use of the seas.” ^{Footnote 73} The representative of China commented specifically on the notion that freedom of navigation through straits was necessary to develop international trade:

Some delegations, such as Denmark, were also strongly of the view that the issue of the right of overflight above international straits would be more appropriately dealt with outside a convention devoted to the law of the sea. ^{Footnote 75} The representative from Ghana argued that the question of overflight should be regulated within the framework of the Chicago Convention on International Civil Aviation (Chicago Convention) or another agreement, but not at the current Conference. ^{Footnote 76} The representative of Algeria emphasized that his country’s draft articles did not refer to the question of overflight because his delegation shared the opinion that the topic should be dealt with not by the Conference but rather, by other existing bodies. ^{Footnote 77} The Nigerian delegation simply stated, somewhat bluntly, that “all reference to freedom of overflight should be deleted in the drafts of the United Kingdom and the socialist countries.” ^{Footnote 78}

However, the position and arguments put forward by countries such as the United States eventually rallied the great majority of participating delegations. During the second session of UNCLOS III, the US delegation “noted with satisfaction that most of the recently introduced proposals concerning transit through straits included the essential element of transit by aircraft.” ^{Footnote 79} The American representative emphasized that questions related to overflight of aircraft were inseparably linked to the law of the sea in the Geneva Conventions: ^{Footnote 80}

The Bulgarian delegation was also of the view that the right of overflight was closely connected with the regime of straits since it was an important part of the global system of communications. It strenuously opposed the idea that prior authorization by the coastal state should be required for the transit of warships or military aircraft. Such a criterion might give rise to serious problems by permitting the granting or refusal of access to straits for subjective reasons, which might very often be arbitrary or political:

The 1974 UK draft, which greatly influenced the consensus text presented by the Fiji/UK Group and which essentially became the foundation for Part III of the LOSC, quite clearly extended the right of transit to military vessels and aircraft: “Article 1(1): In straits to which this article applies, all ships and aircraft enjoy the right of transit passage, which shall not be impeded.” ^{Footnote 83} State aircraft were also directly referenced in draft Article 3 of the UK proposal:

Recognizing that the majority’s interest in guaranteeing the right of transit passage for civilian and state craft could no longer be swayed, some delegations sought until the very last sessions of UNCLOS III to better define within the straits regime the duties and obligations of military aircraft in exercising their right of transit passage. Greece, for example, insisted that there was room for improvement in the informal composite negotiating text so far as “the rules and procedures relating to safe overflight were concerned.” ^{Footnote 85} According to the proposed Greek amendments, state aircraft would have been compelled to comply with the Rules of the Air established by the International Civil Aviation Organization (ICAO) (“state aircraft shall also comply with such rules”), and states bordering straits would have been given the right to “prescribe air traffic procedures.” ^{Footnote 86}

The Moroccan delegation proposed not only to make observance of the Rules of the Air established by ICAO mandatory, even for state aircraft, but would also have included a list of prohibited activities:

1. 3. Aircraft in transit shall:

   1. 1. Refrain from the following activities in the strait zone:

      1. a. Exercises or firing practice of any kind;

      2. b. The use of weapons of any kind;

      3. c. The taking of photographs;

      4. d. Low altitude flights over shipping;

      5. e. Dive-bomber flying;

      6. f. Refuelling while in flight;

      7. g. Any act designated to interfere with the telecommunications system or other installations of the State bordering the strait. ^{Footnote 87}

These Greek and Moroccan proposals, however, were not reflected in the informal composite negotiating text (Revision 1), which was issued after the completion of the eighth session of the Conference in August 1979.

Spain, however, refused to accept defeat and, in a written statement submitted on 26 August 1980 before the collegium started to prepare a third revision of the informal composite negotiating text, expressed its concern that under the current version of Article 39(3)(a), state aircraft were subject to practically no regulation,

While the collegium duly took note of the statements made during the course of the ninth session, the text of the third revision under “Part III: Straits Used for International Navigation” was exactly the same as that in the second revision of the informal composite negotiating text, except for two minor word replacements.

At the very last hour, towards the end of the first part of the eleventh session (in April 1982), delegations were given a final opportunity to submit formal amendments to the draft Convention. Spain was the only country to do so and proposed three amendments, including deleting the word “normally” in Article 39(3)(a). ^{Footnote 89} As the Spanish representative once again argued, “to say that military aircraft should ‘normally’ comply with safety measures imposed no actual obligation on them at all, nor was there any indication of who would decide what was normal and what criteria would be applied.” ^{Footnote 90} As drafted, Article 39(3) would leave military aircraft “virtually unlimited freedom” and would therefore represent a threat to coastal states bordering straits and for international civil aviation in general. The Spanish amendment was put to the vote at the 176^th plenary meeting on 26 April 1982 and was rejected by fifty-five votes to twenty-one, with sixty abstentions.

During the final days of the eleventh session, on 6–10 December 1982, delegations were given a last opportunity to state their views in plenary. However, in light of time constraints, the president of the Conference announced at the 185^th plenary meeting, on 6 December 1982, that delegations that were unable to take the floor or who had been obliged to deliver an abridged version of their statements would be given the opportunity to submit written statements. It is in this context that the Spanish delegation offered a final assessment of the import of some of the key provisions under Part III of the draft Convention: “It is the Spanish Government’s interpretation that the regime established in part III of the Convention is compatible with the right of the coastal State to issue and apply its own air regulations in the air space of the straits used for international navigation so long as this does not impede the transit passage of aircraft.” And further, “with regard to article 39, paragraph 3, it takes the word ‘normally’ to mean ‘except in cases of force majeure or distress’.” ^{Footnote 91}

The LOSC was adopted and opened for signature at Montego Bay, Jamaica, on 10 December 1982. As the records of the lengthy negotiations that shaped Part III on Straits Used for International Navigation amply demonstrate, the issue of passage through straits placed the major naval powers on one side and coastal states controlling narrow straits on the other. However, according to the UN Division for Ocean Affairs and the Law of the Sea, the Convention ultimately reached an acceptable compromise by defining a new concept “that combines the legally accepted provisions of innocent passage through territorial waters and freedom of navigation on the high seas. The new concept of “transit passage” required concessions from both sides. ^{Footnote 92} The next section of this article will take a closer look at the mechanics of the straits regime created by the LOSC to determine whether it can accurately be described as a win-win situation for both groups of states.

The Rules Governing Air Navigation above the NWP

It may be helpful at the outset to reproduce some of the key provisions of Part III of the LOSC that relate to the right of overflight above international straits:

To assess the effective level of protection afforded to states bordering straits in regard to the right of overflight, the legal rules applicable to the airspace above the NWP, if it were considered an international strait, will be contrasted with the legal regime that currently applies in what is considered unqualified sovereign Canadian airspace. In analyzing the legal regime governing the right of overflight above “straits used for international navigation”, attention will first be given to the source and nature of the rules governing such air navigation and subsequently, to the question of access. It will also be useful to distinguish between civilian aircraft and state or military aircraft.