When Nena first performed 99 Red Balloons, little could they have known the cultural significance the lyrics would have in a geopolitically divided and sensitive world four decades later. Buoying these lyrics, this commentary explores some of the legal issues raised by reports of wayward balloons and their unauthorised entry into sovereign airspace.
“There’s something here from somewhere else”
The balloon[1] that has been the focus of most attention reportedly already entered United States (US) airspace over Alaska on 28 January 2023, and on 2 February the US Pentagon publicly acknowledged its presence.[2] Another balloon, later confirmed also to be of Chinese origin, has flown over Costa Rica, Colombia and Venezuela.
The trajectory of the high-altitude balloon has been traced by a meteorologist. The balloon that entered Canadian and US airspace appears to have originated from central China, and flew through Alaska, British Columbia, and then “h[ung] out for a longer period of time” over Montana, where a vital part of the US nuclear arsenal is housed.
“…to identify, to clarify and classify”
On 3 February, China confirmed that the “balloon” is in fact “a civilian airship used for research, mainly meteorological, purposes” that possesses “limited self-steering capability”. However, the term airship (飞艇, fei ting3) implies that it is much more manoeuvrable[3] than a balloon that is “at the mercy of the winds”. Even according to Chinese regulators, a distinction is made between a balloon and an airship, [4] with the latter being defined as an “engine-propelled, lighter-than-air, maneuverable aircraft”.[5]
The International Civil Aviation Organization (ICAO), a specialised agency of the United Nations, uses the specific legal jargon of “unmanned free balloon”, which in turn is defined as a “non-power-driven, unmanned, lighter-than-air aircraft in free flight”.[6] Shedding further light to the issue of manoeuvrability, according to international standards, the right-of-way of aircraft differs and depends on how manoeuvrable the aircraft involved are,[7] with airships needing to give way to balloons due to the fact that the latter cannot move on their own.[8]
The US Pentagon and technical experts have noted that due to its size and ability to change course, the object’s “[manoeuvrability] is beyond the capabilities of most high-altitude balloons”. Typical weather balloons are only around 20 feet across, whereas the Chinese object has been described as being the size of three school buses.
The manufacturer of the balloon is a company that reportedly is a Chinese People’s Liberation Army-affiliated research and design institute, while a series of research papers demonstrate China’s “surging interest in using balloon technology for military purposes”. Despite repeating that the objects are “of civilian nature”, Beijing does not provide more information on which private companies the balloons belong to, or what kind of research or meteorological data were gathered over the US and elsewhere.
“Panic bells, it’s red alert”
US officials claim that “Chinese balloons have previously been spotted over countries across five continents, including in East Asia, South Asia, and Europe”, and that such intrusions of sovereignty “are unacceptable”. Canada also noted that “China’s high-altitude surveillance balloon [...] has violated U.S. and Canadian airspace and international law”.
Balloons share an intimate history with military surveillance,[9] as well as the development of air law. The first “real trace of aviation law in history” was adopted in Paris in 1784 shortly after crewed balloons lifted into the air.[10] There has been a long history of balloons flying into the sovereign airspace of other States, all of which were met with protest by the overflown States and/or attempts to bring them down.
Hundreds of balloons released by the US Air Force as part of Project Genetrix in 1956 overflew parts of Eastern Europe and the then Soviet Union, drawing diplomatic protests from various governments. In 1995, two American balloonists taking part in a race were shot down by Belarus after their balloon strayed too close to restricted airspace. In 1998, a Canadian weather balloon, having survived over 1,000 rounds of ammunition, drifted across the Atlantic and into British, Norwegian, and Russian airspaces before eventually crashing in Finland. Underlining that the recent Chinese ballooning activities “contravene international law, breach the airspace of other countries, and violate their sovereignty”, Taiwan reported that in 2021 and 2022 multiple balloons used by the Chinese military flew over the island nation.
Thus, in law and based on the practice of States, overflight is strictly prohibited and States will, if necessary, shoot down the objects that have infringed their sovereignty and sovereign airspace.
The intrusion into US airspace by the Chinese balloon comes at a time when the two countries are at loggerheads with one another over a variety of reasons, including disagreements over Taiwan, the ongoing technology and trade war, as well as reports that China is providing military aid to support Russia’s war in Ukraine.
Beijing’s reaction has (so far) been limited to issuing threats of retaliation, with the Chinese Ministry of Foreign Affairs noting that “China will resolutely safeguard the legitimate rights and interests of the company concerned, and reserves the right to make further responses if necessary”. While denying the balloon belongs to the Chinese government, the Chinese Ministry of National Defense released a statement that the use of force against a “civilian unmanned airship” was “an obvious overreaction”, and stated that China “reserve[s] the right to use necessary means to deal with similar situations”.
“dass sowas von sowas kommt”
(That something comes from something)
Despite the freedom to conduct remote sensing using a variety of high-spectrum imaging satellites from outer space, many militaries, including that of the US, Australia and Germany, are rediscovering the utility of balloons to provide intelligence, surveillance and reconnaissance (ISR) due to their endurance, and ability to stay stationary above targets for long periods of time. Even in the US, high-altitude balloons have been tested at a similar height in the stratosphere to “provide a persistent surveillance system to locate and deter narcotic trafficking and homeland security threats”.
As the most recent wayward balloon incident demonstrates, high-altitude balloons are difficult to detect as well as intercept. Though the exact delimitation between outer space and airspace is as yet unsettled, it is clear that a balloon navigating at 60,000 ft (or around 18 km above sea level) is within the airspace of the overflown State.
The 1944 Chicago Convention clearly stipulates that “every State has complete and exclusive sovereignty over the airspace above its territory”,[11] a principle the International Court of Justice held is reflective of “firmly established and longstanding tenets of customary international law”.[12] The Chicago Convention applies to civil (as opposed to state) aircraft,[13] which in turn is defined as “any machine that can derive support in the atmosphere from the reactions of the air other than the reactions of the air against the earth’s surface”.[14] Whether it is an airship, as per the Chinese government, or a balloon, per the US, Canada and other overflown States, both categories of aerial objects fall under the definition of aircraft, and are therefore subject to international air law.
It is known that the balloon/airship is uncrewed. A pilotless aircraft cannot be flown “over the territory of a contracting State without special authorization”.[15] More specifically, presuming the object is a balloon, according to ICAO standards, an unmanned balloon cannot be operated “without appropriate authorization from the State from which the launch is made”.[16] In addition, a heavy unmanned balloon, of which the object in question appears to be, may not be “operated across the territory of another State without appropriate authorization from the other State concerned”.[17] Further, China must ensure that the balloon is “operated in such a manner as to minimize hazards to persons, property or other aircraft”.[18]
Thus, the incursion of the balloon into foreign airspace is a violation of international law, as is the flying pilotless aircraft, including balloons, over the territory of another State without authorisation.
Evidence suggests China did not obtain authorisation from the overflown States of Canada and the US (or other States in Latin America). In fact, the Chinese government only admitted to the fact that two aerial objects originating from China were overflying other States after sightings by commercial airline pilots and the public. China also did not make the necessary notification to air traffic services about the launch and the trajectory of the balloon.[19] Additionally, China did not fulfil its obligation to terminate the operation of the balloon prior to the unauthorised entry into the airspace over another State’s territory.[20]
If the object in question were categorised as a military aircraft, as many States and experts believe it is, there is even less of a right to overfly the territory of another State according to the Chicago Convention.[21] Even assuming the aerial object is a civilian aircraft, as China claims, it has been argued that the legal characterisation of an aircraft depends on its “actual ‘use’”.[22]Thus an object that on the surface is a civil aircraft but used for military purposes may be deemed to be a military aircraft.
There are no specific international standards addressing the use or operation of airships, particularly across international borders. This may be the reason China insists that the object is an airship, and not a balloon.
“…wer hätte das gedacht Dass es einmal soweit kommt”?
“…who would've thought that things would someday go so far”?
Beijing admitted the trajectory of the Chinese airship deviated from its course due to Westerlies and the limited steering capabilities of the vehicle. Acknowledging the object intruded the sovereign airspace of other States, China stated it has “no intention to violate and has never violated the territory or airspace of any sovereign country”. Subsequently, the Chinese Ministry of Foreign Affairs expressed regret for the unintended entry of the airship, and clarified that the entry into US airspace “due to force majeure was totally unexpected and accidental”.
Under international law, there are several circumstances a State may be precluded from what normally would constitute an internationally wrongful act,[23] and the State invoking the preclusion of wrongfulness must shoulder the burden of proof to “justify or excuse its conduct”.[24]
Incursion of foreign airspace is a wrongful act, and “the State of the violating aircraft would face international responsibility for the infraction”.[25] For force majeure to be successfully pleaded, there must be an “irresistible force or [...] an unforeseen event” beyond the control of the State which makes it “materially impossible in the circumstances to perform the obligation”.[26] Though the irresistible force or unforeseen event may be due to a natural phenomenon,[27] such as the Westerlies, it would be difficult to argue the balloon had to encroach into foreign airspace due to the “absolute and material impossibility”[28] of a situation. Furthermore, force majeure cannot be invoked if the circumstances were brought about by the conduct of the State invoking this preclusion of wrongfulness,[29] and it is not possible to invoke force majeure if “the State has assumed the risk of that situation occurring”.[30]
If the object indeed had limited steering capability, the balloon was adrift before reaching Alaska, before encroaching Canadian airspace and certainly before re-entering US airspace. If China was indeed aware of the Westerlies and could not, as it argued, manoeuvre its “airship”, China did nothing to forewarn Canadian or US authorities. Further, the Westerlies cannot explain why the other balloon drifted into Latin America as the balloons seem to have taken very different trajectories. Admitting that the object was not easily manoeuvrable, and being fully aware of the existence of prevailing winds, China can be said to have assumed the risk of the situation, and thus is not justified in invoking force majeure.
After over 10 days adrift, the wayward balloon was eventually shot down by the US Air Force over US territorial waters on 4 February 2023. The Vice Foreign Minister of China describes the shoot-down as an “abusive use of force towards the civilian airship”. There are unfortunately ample incidents of the shooting down of civil aircraft carrying passengers onboard which have lead to the loss of many innocent civilian lives.[31] As a result, Article 3bis was added to the Chicago Convention, which explicitly prohibits “resorting to the use of weapons against civil aircraft in flight”.[32]
However, the provision prohibiting the use of weapons against civil aircraft is grounded by the “elementary considerations of humanity" and "the safety and the lives of persons”.[33] Indeed, the provision was adopted after the downing of Korean Air Lines Flight 007, and as such, it is arguably only relevant with respect to commercial passenger airliners.[34] The Chinese object which overflew Canada and the US was neither an airliner, nor were any person on board.
In fact, Article 3bis was added to the Chicago Convention based on the recognition that States are entitled to take appropriate measures to safeguard their aerial sovereignty and rights and obligations under the Charter of the United Nations,[35] while other States must not violate other States’ airspace nor use “civil aviation for purposes inconsistent with the aims of the Convention”.[36] If indeed a civil aircraft were used for for the purposes of military surveillance and reconnaisance, that would arguably be inconsistent with the Chicago Convention and the entire global governance of international civil aviation.
In response to a clear and flagrant violation of US sovereignty, the US had a right to proportionately respond to a threat above its territory and to its national security, and “international custom and the principles of law do not exclude the use of force” to address such threats.[37] Japan, which is now investigating possible links between the recent Chinese balloons and balloons that flew over Japanese territory in 2020 and 2021, has publicly hinted that it reserves the right to use weapons to "deal with airspace intrusions" and "do what is necessary to protect the lives and property of the Japanese public". Even back in 2019, Chinese state media showed its own air force shooting down a balloon that could “endanger [the] security of air defense.”
Indeed, as has been alluded to, there is a long-standing practice of States shooting down balloons that have encroached into their sovereign airspace. Conversely, China has an obligation to ensure that its civil aircraft (as it claims they are), whether piloted or not, are not used in violation of international law and do not infringe the sovereign rights of other States.
To prevent further such incidents, particularly ones that may contribute to "the heightened tensions between China and the US", perhaps ICAO should adopt a resolution clarifying the rights and obligations of States in relation to the use of civilian balloons and/or airships, and stating how to respond to unmanned aircraft that enter into foreign sovereign airspace in a manner that does not endanger the safety and security of international civil aviation.
While the curious case of the wayward balloons provides much food for thought for aviation and international lawyers, it also demonstrates another unfortunate showdown between the United States and China. It is hoped that all parties concerned behave in accordance with international law, and avoid actions and reactions that can further inflate distrust and tensions.
[1] For convenience, the aerial object will predominantly be referred to as “balloon” throughout this article. It should be acknowledged that China calls the object “airship”.
[2] The US Department of Defense also noted that “the balloon is […] traveling at an altitude well above commercial air traffic and does not present a military or physical threat to people on the ground”: US DoD, “DoD Statement on High-Altitude Surveillance Balloon”, online: US DoD <https://www.defense.gov/News/Releases/Release/Article/3287173/dod-statem....
[3] See e.g. US, 14 CFR 1.1 [“Airship means an engine-driven lighter-than-air aircraft that can be steered” whereas “Balloon means a lighter-than-air aircraft that is not engine driven, and that sustains flight through the use of either gas buoyancy or an airborne heater”]; Australia, Civil Aviation Safety Regulations 1998, Reg 202.900 ["airship" means a powered, lighter-than-air aircraft”]; [“‘balloon’ means an unpowered, lighter-than-air aircraft”]; and European Aviation Safety Agency, Notice of Proposed Amendment 2014-29 (A), Annex I, FCL.010 [“‘Airship’means a power-driven lighter-than-air aircraft […]”]; [“‘Balloon’ means a lighter-than-air aircraft which is not engine-driven and sustains flight through the use of either gas or an airborne heater”].
[6] ICAO, Annex 2 to the Convention on International Civil Aviation, Rules of the Air, 10th ed (July 2005) [Annex 2], Definitions (emphasis added).
[7] Ibid, Sect 3.2.2.3.
[8] Indeed, the ICAO designators between an air ship and balloon are different: see ICAO, Aircraft Type Designators, ICAO Doc 8643.
[9] Paul S. Dempsey, Public International Air Law, 2nd ed (Montreal: Centre for Research in Air and Space Law, 2015) 12-13; and Michael Milde, International Air Law and ICAO, 3rd ed (The Hague: Eleven International Publishing, 2016) at 7-10.
[11] Convention on International Civil Aviation, 7 December 1944, 15 UNTS 295, ICAO 7300/9 (entered into force 4 April 1947), art 1 [Chicago Convention].
[12] Military and Paramilitary Activities in and against Nicaragua (Nicaragua v United States of America), [1986] ICJ Rep 14 [Nicaragua], para 212.
[13] Chicago Convention, supra note 11, art 3.
[14] Annex 2, supra note 6; ICAO, Annex 7 to the Convention on International Civil Aviation, Aircraft Nationality and Registration Marks, 6th ed (July 2012); and ICAO, Annex 11 to the Convention on International Civil Aviation, Air Traffic Services, 15th ed (July 2018).
[15] Chicago Convention, supra note 11, art 8. Additionally, assuming that the aerial object carries photographic apparatus, Article 36 of the Chicago Convention specifically confirms the right of the overflown State to "prohibit or regulate the use of photographic apparatus in aircraft over its territory".
[16] Annex 2, supra note 6, Sect 2.1.
[17] Ibid, Appendix 2, Sect. 2.2.
[18] Ibid, Sect 3.1.9.
[19] Ibid, Appendix 2, Sect. 5.1.
[20] Ibid, Appendix 2, Sect. 4.2.
[21] Chicago Convention, supra note 11, art 3(c). Article 3(b) of the Chicago Convention provides that “[a]ircraft used in military, customs and police services shall be deemed to be state aircraft”. See also ICAO, Draft Brief for the ICAO Observer to the Legal Subcommittee of the UN Committee on the Peaceful Uses of Outer Space, ICAO Doc C-WP/8158 (1986) ["[...] an unconditional right of passage through the sovereign airspace does not exist [...] with respect to civil aircraft and is specifically subject to a special authorization with respect to State aircraft and pilotless aircraft"].
[22] Milde, supra note 9 at 73-75 (examples of the blurred distinction between “state aircraft” and “civil aircraft”); and Dempsey, supra note 9 at 63.
[23] See ILC, Responsibility of States for Internationally Wrongful Acts, 53 UN GAOR Supp (No. 10) at 43, UN Doc A/56/83 (2001) [Articles on State Responsibility], Ch V. Other than force majeure, other defences precluding wrongfulness are consent, countermeasures, self-defence, distress and necessity.
[24] Nicaragua, supra note 12, para 101 [“it is the litigant seeking to establish a fact who bears the burden of proving it”]. See also ILC, Draft articles on Responsibility of States for Internationally Wrongful Acts, with commentaries, UN Doc A/CN.4/SER.A/2001/Add.1 [Commentaries to Draft Articles on State Responsibility] at 72.
[25] Milde, supra note 9 at 68.
[26] Articles on State Responsibility, supra note 23, art 23(1).
[27] Commentaries to Draft Articles on State Responsibility, supra note 24 at 76. See also Lighthouses Arbitration (France v Greece) (1963) XII RIAA 155.
[28] Case concerning the difference between New Zealand and France concerning the interpretation or application of two agreements, concluded on 9 July 1986 between the two States and which related to the problems arising from the Rainbow Warrior Affair, (1990) XX UNRIAA, para 77 (emphasis added).
[29] Articles on State Responsibility, supra note 23, art 23(2)(a). See Libyan Arab Foreign Investment Company v Burundi, (1994) 96 ILR 279, para 55 [“the impossibility is the result of a unilateral decision of that State”]. See also Vienna Convention on the Law of Treaties, 23 May 1969, 1155 UNTS 331 (entered into force 27 January 1980), art 61(2).
[30] Articles on State Responsibility, supra note 23, art 23(2)(b)
[31] See Milde, supra note 9 at 53-57. See also Brian E. Foont,”Shooting down Civilian Aircraft: Is There an International Law” (2007) 72 J Air L & Com 695.
[32] Chicago Convention, supra note 11, art 3bis(a).
[33] See Protocol relating to an Amendment to the Convention on International Civil Aviation, ICAO Doc 9436, Preamble, para 5.
[34] Dempsey, supra note 9 at 64. See also ICAO, Minutes of the Council, Extraordinary Session, 15-16 September 1983, ICAO Doc 9416-C/1077 (1983).
[35] Chicago Convention, supra note 11, art 3bis(a). See also Milde, supra note 9 at 62 [“The use of force, even of weapons, in such case cannot be ruled out by international law”]
[36] Protocol relating to an Amendment to the Convention on International Civil Aviation, supra note 34, Preamble, para 6-7.
[37] Milde, supra note 9 at 59.
The author would like to acknowledge Professor Ram Jakhu, Mr. Jack Nelson and Ms. Rachel Pachoud for their review and suggestions. All opinions, omissions, and errors remain that of the author.
All facts and information are accurate and up-to-date on the date of publication.