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XIV Air and Space Warfare

Chapter Contents

14.1 Introduction 14.2 Legal Boundaries of Airspace 14.3 Aircraft Status 14.4 Status of Aircrew on Military Aircraft 14.5 Measures Short of Attack: Interception, Diversion, and Capture 14.6 Belligerent Control of Aviation in the Immediate Vicinity of Hostilities 14.7 Airspace Zones 14.8 Attacks Against Military Objectives in the Air 14.9 Air Attacks Against Military Objectives on the Ground 14.10 International Law And Warfare in Outer Space

14.1 INTRODUCTION

This Chapter addresses the international law applicable to U.S. air and space operations during international armed conflict. This Chapter also discusses the application to air operations of some of the law of war rules discussed elsewhere in this manual.

Air Force publications have provided discussion of other aspects of public international law relating to air operations, including discussion of rules applicable during peacetime.1

Application of the 1944 Chicago Convention With Respect to Military Aircraft 14.1.1and With Respect to States Rights During Armed Conflict. The 1944 Chicago Convention primarily addresses States obligations regarding international civil aviation.2 The 1944 Chicago Convention does not restrict State action during war.3 In addition, the 1944 Chicago Convention generally is not applicable to State aircraft.4 However, the 1944 Chicago Convention imposes requirements with respect to entry by State aircraft into foreign airspace and with respect to the issue of due regard for the safety of navigation of civil aircraft.5

14.1.1.1 1944 Chicago Convention and Freedom of Action of States During Armed Conflict. According to Article 89 of the 1944 Chicago Convention, [i]n case of war, the provisions of this Convention shall not affect the freedom of action of any of the contracting 1 See, e.g., Department of the Air Force, The Judge Advocate Generals School, Air Force Operations and The Law (3rd ed., 2014); 1976 AIR FORCE PAMPHLET 110-31. 2 1944 CHICAGO CONVENTION preamble (THEREFORE, the undersigned governments having agreed on certain principles and arrangements in order that international civil aviation may be developed in a safe and orderly manner and that international air transport services may be established on the basis of equality of opportunity and operated soundly and economically; Have accordingly concluded this Convention to that end.). 3 Refer to 14.1.1.1 (1944 Chicago Convention and Freedom of Action of States During Armed Conflict). 4 Refer to 14.1.1.2 (1944 Chicago Convention and Military Aircraft or Other State Aircraft). 5 Refer to 14.1.1.3 (Requirement for State Consent Prior to Entry by Foreign State Aircraft); 14.1.1.4 (Due Regard for the Safety of Navigation of Civil Aircraft).

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States affected, whether as belligerents or as neutrals.6 Article 89 may be understood as an example, reflected in this case in the Convention, of the application of the general principle that the law of war, as a body of law specially adapted to the circumstances of armed conflict, is the controlling body of law with respect to armed conflict.7 Under Article 89, a States rights under the law of war (and the law of neutrality) would prevail in the event of conflict with obligations under the 1944 Chicago Convention.

The provisions of the 1944 Chicago Convention may be relevant during armed conflict insofar as they articulate restrictions that continue to apply to civil aircraft. For example, neutral civil aircraft engaged in international navigation would still be required to seek permission from a foreign neutral State before carrying munitions of war or implements of war through that neutral States airspace.8

The 1944 Chicago Conventions requirements with respect to entry by State aircraft into foreign airspace and with respect to the issue of due regard for the safety of navigation of civil aircraft are discussed below.9

14.1.1.2 1944 Chicago Convention and Military Aircraft or Other State Aircraft. The 1944 Chicago Convention provides generally that the Convention shall be applicable only to civil aircraft, and shall not be applicable to state aircraft.10 State aircraft include aircraft used in military service.11 The United States has made statements interpreting this provision of the 1944 Chicago Convention.12

6 1944 CHICAGO CONVENTION art. 89 (In case of war, the provisions of this Convention shall not affect the freedom of action of any of the contracting States affected, whether as belligerents or as neutrals.). 7 Refer to 1.3.2 (The Law of Wars Relationship to Other Bodies of Law). 8 See, e.g., 1944 CHICAGO CONVENTION art. 35(a) ((a) No munitions of war or implements of war may be carried in or above the territory of a State in aircraft engaged in international navigation, except by permission of such State. Each State shall determine by regulations what constitutes munitions of war or implements of war for the purposes of this Article, giving due consideration, for the purposes of uniformity, to such recommendations as the International Civil Aviation Organization may from time to time make.). 9 Refer to 14.1.1.3 (Requirement for State Consent Prior to Entry by Foreign State Aircraft); 14.1.1.4 (Due Regard for the Safety of Navigation of Civil Aircraft). 10 1944 CHICAGO CONVENTION art. 3(a) (This Convention shall be applicable only to civil aircraft, and shall not be applicable to state aircraft.). 11 Refer to 14.3.1 (State Versus Civil Aircraft). 12 See, e.g., Department of State Airgram CA-8085, Feb. 13, 1964, quoting U.S. Inter-Agency Group on International Aviation (IGIA) Doc. 88/1/1C, MS, Department of State, file POL 31 U.S., IX WHITEMANS DIGEST 430-31 (The Chicago Convention expressly excludes state aircraft from its scope and thus from the scope of ICAO [International Civil Aviation Organization] responsibility. The United States intends that its state aircraft will follow the ICAO procedures set forth in Annex 2 [Rules of the Air] to the greatest extent practicable; however, the United States considers that state aircraft of any nation are subject to control and regulation exclusively by that nation (unless operating within airspace over which another nation has sovereignty). With respect to State aircraft, contracting States need not undertake any commitment, and the United States does not undertake any commitment, to other nations as to the rules and regulations which any specific state aircraft or class of state aircraft will follow, except when issuing regulations for their state aircraft, that they will have due regard for the safety of navigation of civil aircraft (Article 3(d), Chicago Convention).).

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The 1944 Chicago Convention, however, imposes obligations with respect to entry into foreign airspace by State aircraft and an obligation with respect to State aircraft and the safety of navigation of civil aircraft.13

14.1.1.3 Requirement for State Consent Prior to Entry by Foreign State Aircraft. The 1944 Chicago Convention provides that State aircraft (which include military aircraft) are not permitted to enter the airspace of another State without that States consent.14

During armed conflict, the requirement for a States consent to entry into its airspace would generally continue to apply with respect to neutral military aircraft seeking to enter the airspace of foreign States.

This requirement, however, clearly would not apply to belligerent military aircraft conducting operations in enemy airspace.

The requirement for a States consent to entry into its airspace may be characterized as applicable with respect to belligerent military aircraft and a neutral States airspace; however, even if belligerent military aircraft enter neutral airspace with that neutral States consent, such entry may involve violations of neutrality.15

There are exceptions to the requirement for State consent to entry into its airspace by State aircraft in certain cases of violations of neutrality.16

There is an exception during peacetime to the requirement for a States consent to entry into its airspace by foreign State aircraft when such entry is due to distress and there is no reasonable safe alternative.17

14.1.1.4 Due Regard for the Safety of Navigation of Civil Aircraft. The 1944 Chicago Convention also provides that [t]he contracting States undertake, when issuing regulations for their state aircraft, that they will have due regard for the safety of navigation of

13 Refer to 14.1.1.3 (Requirement for State Consent Prior to Entry by Foreign State Aircraft); 14.1.1.4 (Due Regard for the Safety of Navigation of Civil Aircraft). 14 1944 CHICAGO CONVENTION art. 3(c) (No state aircraft of a contracting State shall fly over the territory of another State or land thereon without authorization by special agreement or otherwise, and in accordance with the terms thereof.). 15 Refer to 15.10.2 (Prohibition on Entry by Belligerent Military Aircraft Into Neutral Airspace). 16 Refer to 15.4.2 (Belligerent Use of Self-Help When Neutral States Are Unable or Unwilling to Prevent Violations of Neutrality). 17 U.S. Response to Chinese Legal Views, 2001 DIGEST OF UNITED STATES PRACTICE IN INTERNATIONAL LAW 703, 708 (Although we recognize that military aircraft normally require permission to enter the territorial airspace of another nation, international law recognizes a right of entry for foreign aircraft, state or civil, in circumstances such as these when such entry is due to distress and there is no reasonable safe alternative (Footnote 3 below). Notwithstanding the ordinary rules requiring consent, a peacetime right to enter in distress for military aircraft is consistent with established international practice. Such a right is clearly inferable both from analogous situations in which such a right exists (e.g., for civil aircraft under Article 25 of the Chicago Convention) and from basic humanitarian considerations.).

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civil aircraft.18 Assuming that an obligation to exercise due regard would be applicable during armed conflict, what regard would be due in any particular set of circumstances would depend on military necessity, and other principles and rules of the law of war, which are specially adapted to the circumstances of armed conflict. For example, the use of force against enemy civil aircraft that constitute military objectives and thus may be made the object of attack under the law of war would not be prohibited.19

As reflected in Article 89 of the 1944 Chicago Convention, the Convention does not restrict the freedom of action of States as belligerents or neutrals.20 Nonetheless, as a practical matter, modern air warfare is often conducted in complex airspace, and U.S. forces have routinely and intensively coordinated flight operations with national civil aviation authorities. This coordination is important for a variety of purposes, including ensuring mission accomplishment, avoiding fratricide and mid-air collisions, and ensuring the safety of international civil aviation. DoD policy has required that, in the event of combat operations during armed conflict, aircraft commanders, consistent with military necessity, take measures to minimize hazards to civil air or surface traffic.21

Similarly, under the law of the sea, military operations must be conducted with due regard for the high seas freedom of overflight in international airspace.22

Past Attempts to Conclude Treaties About Air Warfare. Initial attempts to 14.1.2conclude agreements on the law of war governing means and methods in the air context were made during the 1899 and 1907 Hague Peace Conferences, before air power had become a significant factor in warfare. Extensive efforts were made in 1922-23 to adopt a code of laws specifically applicable only to air warfare; however, the proposed rules were not ratified by any State.23 The United States has not ratified a treaty applicable solely to air operations during armed conflict, although the United States has ratified treaties that have included specific

18 1944 CHICAGO CONVENTION art. 3(d) (The contracting States undertake, when issuing regulations for their state aircraft, that they will have due regard for the safety of navigation of civil aircraft.). 19 Refer to 14.8.3 (Attacks Against Civil Aircraft). 20 Refer to 14.1.1.1 (1944 Chicago Convention and Freedom of Action of States During Armed Conflict). 21 DOD INSTRUCTION 4540.01, Use of International Airspace by U.S. Military Aircraft and for Missile/Projectile Firings, 4.2.3 (Mar. 28, 2007) (In the event of combat operations in time of war, armed conflict, national emergency, situations requiring self-defense, or similar military contingencies, aircraft commanders shall, consistent with military necessity, take measures to minimize hazards to civil air or surface traffic. Such actions shall be of no greater extent or duration than required by military necessity.); DOD DIRECTIVE 4540.1, Use of Airspace by U.S. Military Aircraft and Firings Over the High Seas, 6b (Jan. 13, 1981) (In the event of combat operations in time of war, armed conflict, national emergency, situations requiring self-defense, or similar military contingencies, departure from the operating procedures in this Directive may be required. In all such instances, however, all possible precautions shall be taken to minimize any hazard to the safety of other air and surface traffic and departure from procedures set forth in this Directive shall be of no greater extent or duration than is required to meet the contingency.). 22 Refer to 13.1.1 (The Law of the Sea During Armed Conflict). 23 Refer to 19.11 (1923 Hague Air and Radio Rules).

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references to aspects of war in the air, such as protection for medical aircraft in the 1949 Geneva Conventions.24

14.2 LEGAL BOUNDARIES OF AIRSPACE

The legal classifications of airspace may be relevant to the application of the law of war and therefore may affect military operations during armed conflict by:

determining whether airspace is neutral airspace;25

determining the authority that a belligerent State has with respect to neutral aircraft in an area; or

determining the authority that a neutral State has with respect to belligerent aircraft in an area.

Lateral Boundaries of Airspace. The lateral boundaries of the airspace are 14.2.1determined by the status of the land or water directly beneath them.

Airspace is often divided between national airspace (i.e., airspace over a States land territory, internal waters, territorial seas, and archipelagic waters), which is subject to the sovereignty of a State, and international airspace, which is not subject to the sovereignty of any State.26 In addition, special rules apply to international straits and archipelagic sea lanes.27

The division between national airspace and international airspace is similar to the division between national waters and international waters.28 One notable distinction, however, is that aircraft do not enjoy the same right of innocent passage over territorial seas that ships enjoy through territorial seas.29

14.2.1.1 National Airspace. Every State has complete and exclusive sovereignty over the airspace above its territory.30 In other words, a State has sovereignty over the airspace that is above land or waters that are subject to its sovereignty.31 Thus, a States national airspace includes:

24 Refer to 7.14 (Military Medical Aircraft); 7.19 (Civilian Medical Aircraft). 25 Refer to 15.10 (Neutral Airspace). 26 Refer to 14.2.1.1 (National Airspace); 14.2.1.2 (International Airspace). 27 Refer to 15.8 (Passage of Belligerent Vessels and Aircraft Through International Straits and Archipelagic Sea Lanes). 28 Refer to 13.2.2 (National Waters); 13.2.3 (International Waters). 29 Refer to 13.2.2.4 (Innocent Passage of Foreign Vessels Through Territorial Seas and Archipelagic Waters). 30 1944 CHICAGO CONVENTION art. 1 (The contracting States recognize that every State has complete and exclusive sovereignty over the airspace above its territory.). Cf. 49 U.S.C. 40103 (a)(1) (The United States Government has exclusive sovereignty of airspace of the United States.). 31 See, e.g., 1944 CHICAGO CONVENTION art. 2 (For the purposes of this Convention the territory of a State shall be deemed to be the land areas and territorial waters adjacent thereto under the sovereignty, suzerainty, protection or

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airspace over that States land territory, including its internal waters;32

airspace over that States territorial sea;33 and

airspace over that States archipelagic sea.34

14.2.1.2 International Airspace. International airspace may be understood as all airspace that is not subject to the sovereignty of any State, including:35

airspace over States contiguous zones;36

airspace over States Exclusive Economic Zones;37 and

airspace over the high seas.38

Vertical Boundary Between Airspace and Outer Space. A States sovereignty over 14.2.2its airspace does not extend to outer space, which is not subject to the sovereignty of any State.39

It is generally accepted that orbiting objects are in outer space.40 The United States has expressed the view that there is no legal or practical need to delimit or otherwise define a specific boundary between airspace and outer space.41

mandate of such State.); Convention on the Territorial Sea and Contiguous Zone, art. 2, Apr. 29, 1958, 516 UNTS 205, 208 (The sovereignty of a coastal State extends to the air space over the territorial sea as well as to its bed and subsoil.). Consider LOS CONVENTION art. 2(2) (This sovereignty extends to the air space over the territorial sea as well as to its bed and subsoil.); LOS CONVENTION art. 49(2) (This sovereignty extends to the air space over the archipelagic waters, as well as to their bed and subsoil, and the resources contained therein.). 32 Refer to 13.2.2.1 (Internal Waters). 33 Refer to 13.2.2.2 (Territorial Seas). 34 Refer to 13.2.2.3 (Archipelagic Waters). 35 See, e.g., DOD DIRECTIVE 4500.54E, DoD Foreign Clearance Program (FCP), Glossary (Dec. 28, 2009) (international airspace. All airspace seaward of coastal states national airspace, including airspace over contiguous zones, exclusive economic zones, and the high seas. International airspace is open to all aircraft of all nations. Military aircraft may operate in such areas free of interference or control by the coastal state.). 36 Refer to 13.2.3.2 (Contiguous Zones). 37 Refer to 13.2.3.3 (Exclusive Economic Zones (EEZs)). 38 Refer to 13.2.3.4 (High Seas). 39 Refer to 14.10.1 (Classification of Outer Space). 40 See, e.g., Department of the Air Force, The Judge Advocate Generals School, Air Force Operations and The Law, 85 (3rd ed., 2014) (According to this approach, the upper limit to airspace is above the highest altitude at which an aircraft can fly and below the lowest possible perigee of an earth satellite in orbit. The result is that anything in orbit or beyond can safely be regarded as being in outer space.); 2007 NWP 1-14M 1.10, 2.11.1 (The upper limit of airspace subject to national jurisdiction has not been authoritatively defined by international law. International practice has established that airspace terminates at some point below the point at which artificial satellites can be placed in orbit without free-falling to earth. Outer space begins at that undefined point. Although there is no legally defined boundary between the upper limit of national airspace and the lower limit of outer space, international law recognizes freedom of transit by man-made space objects at earth orbiting altitude and

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Flight Information Regions. Flight Information Regions (FIRs) are areas of 14.2.3airspace allocated by the International Civil Aviation Organization (ICAO). Every portion of airspace belongs to a defined flight information region. Within each flight information region, a flight information service and an alerting service are provided by the national authorities responsible for air traffic control. These services are the most basic levels of air traffic service, and they provide information to aviators necessary for the safe and efficient conduct of flights.42

A flight information region normally encompasses substantial areas of international airspace and does not necessarily reflect international or national airspace borders.43

beyond. A generally acceptable definition is that outer space begins at the undefined upper limit of the earths airspace and extends to infinity.); 2006 AUSTRALIAN MANUAL 8-2 (While views differ as to the precise vertical and horizontal extent of airspace, for practical purposes, it can be said that the upper limit to a states rights in airspace is above the highest altitude at which an aircraft can fly and below the lowest possible perigee of an earth satellite in orbit. The result is that anything in orbit or beyond can safely be regarded as in outer space.); 2004 UK MANUAL 12.13 (Views differ as to the precise vertical and horizontal extent of airspace. For practical purposes, it can be said that the upper limit to a states rights in airspace is above the highest altitude of what an aircraft can fly and below the lowest possible perigee of an earth satellite in orbit. The result is that anything in orbit or beyond can safely be regarded as in outer space.). 41 Kenneth Hodgkins, U.S. Advisor to the United Nations, Legal Subcommittee (LSC) of the United Nations Committee on the Peaceful Uses of Outer Space (COPUOS) 719th Meeting [unedited transcript] (Apr. 8, 2005) (As we have stated on previous occasions, the United States is firmly of the view that there is no need to seek a legal definition or delimitation for outer space. The current framework has presented no practical difficulties and, indeed, activities in outer space are flourishing. Given this situation, an attempt to define or delimit outer space would be an unnecessary theoretical exercise that could potentially complicate existing activities and that might not be able to anticipate continuing technological developments. The current framework has served us well and we should continue to operate under this framework until there is a demonstrated need and a practical basis for developing a definition or delimitation.); Stephen Mathias, U.S. Advisor to the United Nations, U.S. Statements on Specific Agenda Items before the Legal Subcommittee of the Committee on the Peaceful Uses of Outer Space (2003) (At this time, the United States remains convinced that there is no need to seek a legal definition of delimitation for outer space. Activities in outer space and in airspace are flourishing and have raised no practical need for a definition or limitation between the spheres. In the absence of a real need, any attempt to develop a definition would be ill-advised as there would be no experience to call upon in agreeing upon any particular definition or delimitation.); U.S. Statement before the Legal Subcommittee of the United Nations Committee on the Peaceful Uses of Outer Space regarding the Definition and Delimitation of Outer Space and the Character and Utilization of the Geostationary Orbit, Apr. 4, 2001, 2001 DIGEST OF UNITED STATES PRACTICE IN INTERNATIONAL LAW 721 (Our position continues to be that defining or delimiting outer space is not necessary. No legal or practical problems have arisen in the absence of such a definition. On the contrary, the differing legal regimes applicable in respect of airspace and outer space have operated well in their respective spheres. The lack of a definition or delimitation of outer space has not impeded the development of activities in either sphere. It would be dangerous for the Legal Subcommittee to agree to an artificial line between air space and outer space, when it cannot predict the consequences of such a line.). 42 Information Provided to U.S. Embassies in Rangoon and New Delhi Regarding Transit Through Flight Information Regions and International Airspace, May 2007, 2007 DIGEST OF UNITED STATES PRACTICE IN INTERNATIONAL LAW 635, 636 (A Flight Information Region, or FIR, is simply an area over which a civil aviation authority has responsibility for provision of flight information services. FIRs are allocated to coastal states by the International Civil Aviation Organization (ICAO) to facilitate the safety of civil aviation. Some FIRs encompass both national and international airspace. Civil aviation authorities may confuse responsibility for and authority over civil aviation in a FIR for sovereignty over the area.). 43 DOD DIRECTIVE 4500.54E, DoD Foreign Clearance Program (FCP), Glossary (Dec. 28, 2009) (flight information region. An airspace of defined dimensions within which flight information service and alerting service

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Under Article 3 of the 1944 Chicago Convention, flight information region rules do not apply to State aircraft, including military aircraft, and military aircraft are free to operate in international airspace without the consent of or notice to coastal State authorities.44 Thus, for example, a flight information region could not limit the rights of belligerent military aircraft during armed conflict.

Air Defense Identification Zone (ADIZ). In general terms, an ADIZ is an area of 14.2.4airspace over land or water in which the ready identification, location, and control of aircraft may be required in the interests of national security.45 The United States has established ADIZs.46

14.2.4.1 Establishment of an ADIZ. The legal basis for a State to establish an ADIZ is its right to establish conditions and procedures for entry into its national airspace.47

are provided. A flight information region normally encompasses substantial areas of international airspace and does not reflect international or national airspace borders. Responsibility for flight information region management is not the same as territorial authority; therefore, state aircraft are not to request aircraft diplomatic clearance to enter a flight information region if the aircraft will not enter national airspace. The International Civil Aviation Organization establishes flight information regions in accordance with the Convention on International Civil Aviation. Civil aviation authorities of designated nations administer them pursuant to International Civil Aviation Organization authority, rules, and procedures.). 44 Information Provided to U.S. Embassies in Rangoon and New Delhi Regarding Transit Through Flight Information Regions and International Airspace, May 2007, 2007 DIGEST OF UNITED STATES PRACTICE IN INTERNATIONAL LAW 635-36 (A coastal state may establish a FIR in international airspace consistent with the requirements of the 1944 Convention on International Civil Aviation (Chicago Convention), to which your country is a party; however, under Article 3 of that convention, FIR rules do not apply to state aircraft, including military aircraft. State aircraft, including military aircraft, operating in international airspace (whether within or outside a FIR) are free to operate without the consent of or notice to coastal state authorities and are not subject to the jurisdiction or control of the ATC authorities of those states. No notice to, clearance from, or approval of a coastal state is required to exercise such freedoms of navigation and overflight. The United States reaffirms its navigation and overflight rights in international airspace.). 45 14 CODE OF FEDERAL REGULATIONS 99.3 (Air defense identification zone (ADIZ) means an area of airspace over land or water in which the ready identification, location, and control of all aircraft (except for Department of Defense and law enforcement aircraft) is required in the interest of national security.). 46 See, e.g., Ian E. Rinehart & Bart Elias, Chinas Air Defense Identification Zone (ADIZ), 2 (Congressional Research Service, Jan. 30, 2015) (In 1948, the U.S. Air Force designated several offshore areas as active defense areas or defense zones. From these, the first ADIZs in the world were established in 1950, under an Executive order directing the Secretary of Commerce to exercise security control over aircraft. Various defense zones were redesignated as ADIZs (over Atlantic, Pacific, and Gulf of Mexico waters[)] the Alaska ADIZ, the Guam ADIZ, and the Hawaii ADIZ, are codified in Title 14, Part 99, of the Code of Federal Regulations, along with the procedural requirements for flights operating in these designated areas. They are predominantly located over water and typically do not extend to the shore, leaving a narrow strip of sovereign airspace parallel to the coastline that is not within the ADIZ.); 1955 NWIP 10-2 422c endnote 16 (It is apparent that the potential threat to the security of states presented by aircraft is considerably greater than the potential threat presented by vessels. However, there has not yet emerged a recognized practice of contiguous air space zones, analogous to contiguous zones established on the high seas (see paragraph 413d), enabling states to exercise certain legal controls over aircraft flying outside territorial air space. The present system of Air Defense Identification Zones (ADIZ) employed by the United States extends to the air space above the open sea, and is limited to the purpose of identifying aircraft.). 47 See, e.g., 2007 NWP 1-14M 2.7.2.3 (International law does not prohibit nations from establishing air defense identification zones (ADIZ) in the international airspace adjacent to their territorial airspace. The legal basis for

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The establishment of an ADIZ by a State does not constitute a claim to international airspace as its own. The ADIZ is merely a reference point for the initiation of identification procedures for aircraft on a course to enter national airspace.48

Because the establishment of an ADIZ by a State that extends to international airspace does not confer sovereignty over that airspace, the ADIZ, and its implementing regulations and operational practices, must respect the rights of other States to use international airspace.

The United States does not recognize the right of a State to apply its ADIZ laws and regulations to foreign aircraft, either civil aircraft or State aircraft, if those aircraft do not intend to enter the national airspace of that State.49

14.2.4.2 Failure to Comply With Identification Requirements. Failure by an aircraft to identify itself once it enters an ADIZ does not, of itself, entitle the declaring State to use force against that aircraft, although it may subject the aircraft to interception.50 Depending on the circumstances, a persistent failure to comply with instructions may be evidence that the aircraft, in fact, poses a threat to the declaring State.51

Establishment of an ADIZ, like other warning zones, does not relieve the proclaiming State of its obligations under applicable international law, such as its obligation under the law of war to refrain from attacking aircraft that do not constitute lawful military objectives, or its obligation to refrain from attacks against civil aircraft under peacetime international law.52

ADIZ regulations is the right of a nation to establish reasonable conditions of entry into its territory. Accordingly, an aircraft approaching national airspace can be required to identify itself while in international airspace as a condition of entry approval.); 1976 AIR FORCE PAMPHLET 110-31 2-1g (Civil aircraft on a course to penetrate United States airspace are required to identify themselves upon entry into the [Air Defense Identification] zone. This requirement is based on the right of every state to establish conditions and procedures for entry into its airspace.). See also 1944 CHICAGO CONVENTION art. 11 (Subject to the provisions of this Convention, the laws and regulations of a contracting State relating to the admission to or departure from its territory of aircraft engaged in international air navigation, or to the operation and navigation of such aircraft while within its territory, shall be applied to the aircraft of all contracting States without distinction as to nationality, and shall be complied with by such aircraft upon entering or departing from or while within the territory of that State.). 48 1976 AIR FORCE PAMPHLET 110-31 2-1g (An air defense identification zone does not constitute a claim of sovereignty over airspace above the high seas. Such a zone is merely a reference point for initiation of identification procedures for aircraft on a course to penetrate national airspace.). 49 See, e.g., John Kerry, Secretary of State, Press Statement (Nov. 23, 2013) (We dont support efforts by any State to apply its ADIZ procedures to foreign aircraft not intending to enter its national airspace. The United States does not apply its ADIZ procedures to foreign aircraft not intending to enter U.S. national airspace.); U.S. Response to Chinese Legal Views, 2001 DIGEST OF UNITED STATES PRACTICE IN INTERNATIONAL LAW 703, 707 (The U.S. does not recognize the right of a coastal nation to apply its ADIZ procedures to foreign aircraft not intending to enter national airspace, and does not apply its ADIZ procedures to foreign aircraft not intending to enter U.S. airspace.). 50 1976 AIR FORCE PAMPHLET 110-31 2-1g (State aircraft on a course to penetrate United States airspace may be requested to identify themselves, and failing voluntary identification may be identified by intercept aircraft or otherwise as appropriate.). 51 Compare 14.5.2.1 (Failure to Comply by Civil Aircraft). 52 Refer to 13.9.2 (Use of Zones to Warn Vessels or Aircraft War, Operational, Warning, and Safety Zones); 14.8.3.1 (Protection of Civil Aircraft in Peacetime).

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14.3 AIRCRAFT STATUS

State Versus Civil Aircraft. The 1944 Chicago Convention distinguishes between 14.3.1State aircraft and civil aircraft.53

Aircraft used in military, customs, and police services are deemed to be State aircraft for the purposes of the 1944 Chicago Convention.54 More generally, State aircraft may be understood to include other aircraft operated by a government for sovereign, non-commercial purposes.55 In U.S. practice, DoD contract aircraft have not qualified as State aircraft, unless specifically designated as such by the United States.56

The distinction between State aircraft and civil aircraft may be important for a variety of reasons. For example, the 1944 Chicago Convention generally does not apply to State aircraft.57 In addition, enemy State aircraft are subject to seizure as war booty.58 As another example, neutral State aircraft are not subject to visit and search or diversion.59 And, although not

53 1944 CHICAGO CONVENTION art. 3(a) (This Convention shall be applicable only to civil aircraft, and shall not be applicable to state aircraft.). Consider Commission of Jurists to Consider and Report Upon the Revision of the Rules of Warfare, General Report, Part II: Rules of Arial Warfare, art. 2, Feb. 19, 1923, reprinted in 32 AJIL SUPPLEMENT: OFFICIAL DOCUMENTS 12, 12 (1938) (The following shall be deemed to be public aircraft: (a) Military aircraft. (b) Non-military aircraft exclusively employed in the public service. All other aircraft shall be deemed to be private aircraft.). 54 1944 CHICAGO CONVENTION art. 3(b) (Aircraft used in military, customs and police services shall be deemed to be state aircraft.). 55 DOD DIRECTIVE 4500.54E, DoD Foreign Clearance Program (FCP), Glossary (Dec. 28, 2009) (state aircraft. Aircraft, including U.S. military aircraft, operated by a government for sovereign, non-commercial purposes.). 56 See, e.g., Secretary of State Cable 22631, USG Policy Regarding Status of DOD Commercial Contract Aircraft (Mar. 10, 2010) (The U.S. Government has consistently taken the position that Department of Defense (DoD) commercial contract aircraft and other USG contract aircraft are not state aircraft unless the particular aircraft is specifically designated as such by the USG. The normal practice of the USG is not to designate contract aircraft as state aircraft.); 2007 NWP 1-14M 2.4.3 (Auxiliary aircraft are State aircraft, other than military aircraft, that are owned by or under the exclusive control of the armed forces. Civilian owned and operated aircraft, the full capacity of which has been contracted by the DOD and used in the military service of the United States, qualify as auxiliary aircraft if they are designated as State aircraft by the United States. In those circumstances they too enjoy sovereign immunity from foreign search and inspection. As a matter of policy, however, the United States normally does not designate Air Mobility Command-charter aircraft as State aircraft.); Department of the Army, Office of the Judge Advocate General, International and Operations Law: Payment of Fees Charged to State Aircraft, 21 THE REPORTER 19, 20 (June 1994) (The US government consistently has taken the position that Department of Defense contract aircraft do not qualify as state aircraft unless the particular aircraft is specifically designated as such by the US government. Although many SOFAs, base rights, and other agreements grant DoD contract aircraft the same rights of access, exit, and freedom from landing fees and similar charges enjoyed by US military aircraft, such agreements do not have the effect of declaring DoD contract aircraft to be military aircraft or any form of state aircraft.). 57 Refer to 14.1.1.2 (1944 Chicago Convention and Military Aircraft or Other State Aircraft). 58 Refer to 14.5.3 (Capture of Aircraft and Goods on Board Aircraft). 59 Refer to 15.13 (Belligerent Right of Visit and Search of Merchant Vessels and Civil Aircraft); 14.5.2 (Diversion of Aircraft).

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necessary for an aircraft to constitute a military objective, the status of an aircraft as State aircraft may also be an important factor in determining that an aircraft constitutes a military objective.60

Nationality of Aircraft. State aircraft possess the nationality of the State that 14.3.2operates them. Civil aircraft possess the nationality of the State in which they are registered.61

The nationality of an aircraft may be important in assessing whether it constitutes an enemy or neutral aircraft.62

Status of Military Aircraft. Military aircraft may be understood as aircraft that are 14.3.3designated as such by a State that operates them. The United States has not ratified a treaty that requires certain qualifications before an aircraft may be designated as military aircraft.

In general, military aircraft are operated by commissioned units of the armed forces of a State, bearing the military markings of that State, and commanded by a member of the armed forces of that State.

In addition to combat aircraft such as fighters and bombers, other types of aircraft operated by the armed forces of a State may also be designated as military aircraft, such as transport, reconnaissance, and meteorological aircraft. Unmanned aircraft, i.e., aircraft that are remotely piloted or controlled, may also be designated as military aircraft.

14.3.3.1 Military Aircraft Rights and Liabilities. Of all aircraft, only military aircraft are entitled to engage in attacks in armed conflict.63 Likewise, during armed conflict, enemy military aircraft generally constitute military objectives and, thus, may be made the object of attack, whether in the air or on the ground.64 There may be exceptions to the general rule that enemy military aircraft are liable to being made the object of attack, such as in the case of enemy military medical aircraft or enemy military aircraft that have surrendered.65

60 Refer to 14.8.3 (Attacks Against Civil Aircraft); 5.7 (Military Objectives). 61 1944 CHICAGO CONVENTION art. 17 (Aircraft have the nationality of the State in which they are registered.). 62 Refer to 15.14 (Acquisition of Enemy Character by Neutral-Flagged Merchant Vessels and Neutral-Marked Civil Aircraft). 63 See, e.g., 2013 GERMAN MANUAL 1103 (Only military aircraft are entitled to exercise belligerent rights and use military force in fighting military objectives of an adversary (14 13, 16 para.1).); 2006 AUSTRALIAN MANUAL 8-14 ([O]nly military aircraft can exercise the combat rights of a belligerent. Examples of such rights include attacking military objectives and overflying enemy territory.); 2004 UK MANUAL 12.34 (Only military aircraft may carry out attacks.); 2001 CANADIAN MANUAL 704(3) (Civil aircraft and state aircraft that are not military aircraft (for example, police or customs officials) may not engage in hostilities ... .); 1976 AIR FORCE PAMPHLET 110-31 2-6d (Only military aircraft may exercise such rights of belligerents as attacking and destroying military objectives or transporting troops in the adversarys national airspace or behind its lines.). Consider Commission of Jurists to Consider and Report Upon the Revision of the Rules of Warfare, General Report, Part II: Rules of Arial Warfare, art. 16, Feb. 19, 1923, reprinted in 32 AJIL SUPPLEMENT: OFFICIAL DOCUMENTS 12, 19 (1938) (No aircraft other than a belligerent military aircraft shall engage in hostilities in any form.). 64 Refer to 5.7.4.1 (Military Equipment and Bases). 65 Refer to 7.14 (Military Medical Aircraft); 14.8.2 (Protection of Persons Who Surrender or Who Are Otherwise Hors De Combat on Board Enemy Aircraft).

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Belligerent military aircraft generally may not enter neutral airspace.66

As State aircraft, military aircraft, like warships, are customarily accorded certain privileges and immunities by friendly foreign States.67

14.3.3.2 Military Aircraft Markings. Military aircraft are customarily marked to signify both their nationality and military character.68 Markings may help distinguish friend from foe and help preclude misidentification of aircraft as neutral or as civil.69 However, circumstances may exist where such markings are superfluous.70

A single marking may be used to signify both an aircrafts nationality and its military character.71

66 Refer to 15.10.2 (Prohibition on Entry by Belligerent Military Aircraft Into Neutral Airspace). 67 DOD DIRECTIVE 4500.54E, DoD Foreign Clearance Program (FCP), 4 (Dec. 28, 2009) (b. Consistent with U.S. Government policy, DoD aircraft shall not be subject to air navigation, overflight, or similar fees for transit through the national airspace of another country or through Flight Information Regions in international airspace. This policy is based upon the unique status of state aircraft, including U.S. military aircraft, in international law as instruments of a sovereign, and is consistent with international custom and practice. c. DoD aircraft shall not be subject to search, seizure, and inspection (including customs, safety, and agriculture inspections) or any other exercise of jurisdiction by a foreign government over such aircraft, or the personnel, equipment, or cargo on board. DoD aircraft commanders shall not consent to the exercise of jurisdiction by foreign government authorities over U.S. military aircraft, except at the direction of the appropriate DoD Component headquarters.). Consider Convention Relating to the Regulation of Aerial Navigation, art. 32, Oct. 13, 1919, 11 LNTS 173, 195 (No military aircraft of a contracting State shall fly over the territory of another contracting State nor land thereon without special authorisation. In case of such authorisation the military aircraft shall enjoy, in principle, in the absence of special stipulation, the privileges which are customarily accorded to foreign ships of war. A military aircraft which is forced to land or which is requested or summoned to land shall by reason thereof acquire no right to the privileges referred to in the above paragraph.); John Cobb Cooper, A Study on the Legal Status of Aircraft, in IVAN A. VLASIC, EXPLORATIONS IN AEROSPACE LAW 205, 243 (1968) (It is felt that the rule stated in the Paris Convention that aircraft engaged in military services should, in the absence of stipulation to the contrary, be given the privileges of foreign warships when in national port is sound and may be considered as still part of international air law even though not restated in the Chicago Convention.). 68 Consider Commission of Jurists to Consider and Report Upon the Revision of the Rules of Warfare, General Report, Part II: Rules of Arial Warfare, art. 3, Feb. 19, 1923, reprinted in 32 AJIL SUPPLEMENT: OFFICIAL DOCUMENTS 12, 13 (1938) (A military aircraft shall bear an external mark indicating its nationality and military character.). 69 For example, SPAIGHT, AIR POWER AND WAR RIGHTS 82 (Again and again one finds the fighting airmen of 1914-18 stating in their memoirs or diaries that they have been saved from attacking a friend or have been put on guard against a foe by seeing the distinguishing marks on the wings of the machines.). 70 1976 AIR FORCE PAMPHLET 110-31 7-4 (Military aircraft, as entities of combat in aerial warfare, are also required to be marked with appropriate signs of their nationality and military character. However, circumstances may exist where such markings are superfluous and are not required. An example is when no other aircraft except those belonging to a single state are flown. Such markings serve to distinguish friend from foe and serve to preclude misidentification as neutral or civilian aircraft. Accordingly, military aircraft may not bear markings of the enemy or markings of neutral aircraft while engaging in combat. Combatant markings should be prominently affixed to the exterior aircraft surfaces and be recognizable at a reasonable distance from any direction.). 71 For example, 2004 UK MANUAL 12.10.4 (In most air forces, the same marking indicates both nationality and military character, for example, the Royal Air Force roundel.).

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14.3.3.3 Military Aircraft Command and Crew. Military aircraft are commanded by members of the armed forces of that State.72 The crew, however, may include civilian members, and such personnel are expressly entitled to POW status under the GPW.73

14.4 STATUS OF AIRCREW ON MILITARY AIRCRAFT

Military Aircrew. Aircrew who are members of the armed forces of a State have 14.4.1the rights, duties, and liabilities of combatants.74 For example, they are entitled to POW status if they fall into the power of the enemy during international armed conflict, and they have legal immunity from domestic law for acts done under military authority and in accordance with the law of war.

14.4.1.1 Wearing of Uniform by Military Aircrew. Military aircrew are required to distinguish themselves from the civilian population in the same manner as other combatants.75 The wearing of flying clothing distinctive to the armed forces satisfies this requirement. In particular, military aircrew should wear military uniforms (including distinctive flying clothing) in case they become separated from the aircraft.76

Civilian Members of Military Aircrew and Other Persons Authorized to 14.4.2Accompany the Armed Forces. Civilian members of military aircrew fall into the category of persons authorized to accompany the armed forces.77 Other civilians who are present on military aircraft or who support the operations of military aircraft may also fall into the category of persons authorized to accompany the armed forces, provided they have received such authorization.

As persons authorized to accompany the armed forces, civilian members of military aircrews are entitled to POW status if they fall into the power of the enemy during international armed conflict, and they have legal immunity from the enemys domestic law for providing authorized support services to the armed forces. Civilians who work in or on military objectives, such as military aircraft, assume the risk of harm from attacks against military objectives.78

72 Consider Commission of Jurists to Consider and Report Upon the Revision of the Rules of Warfare, General Report, Part II: Rules of Arial Warfare, art. 14, Feb. 19, 1923, reprinted in 32 AJIL SUPPLEMENT: OFFICIAL DOCUMENTS 12, 18 (1938) (A military aircraft shall be under the command of a person duly commissioned or enlisted in the military service of the state;). 73 Refer to 4.15 (Persons Authorized to Accompany the Armed Forces). 74 Refer to 4.5 (Armed Forces of a State); 4.4 (Rights, Duties, and Liabilities of Combatants). 75 Refer to 5.14.5 (Carrying Arms Openly and Wearing of Distinctive Emblems by the Armed Forces to Distinguish Themselves From the Civilian Population). 76 Consider Commission of Jurists to Consider and Report Upon the Revision of the Rules of Warfare, General Report, Part II: Rules of Arial Warfare, art. 15, Feb. 19, 1923, reprinted in 32 AJIL SUPPLEMENT: OFFICIAL DOCUMENTS 12, 18 (1938) (Members of the crew of a military aircraft shall wear a fixed distinctive emblem of such character as to be recognizable at a distance in case they become separated from their aircraft.). 77 Refer to 4.15 (Persons Authorized to Accompany the Armed Forces). 78 Refer to 5.12.3.2 (Harm to Certain Individuals Who May Be Employed In or On Military Objectives).

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Downed Aircrew. There are a number of law of war issues related to downed 14.4.3aircrew.

14.4.3.1 Protection of Aircrew While Parachuting From an Aircraft in Distress. In general, aircrew parachuting from an aircraft in distress are treated as though they are hors de combat, i.e., they must not be made the object of attack.79 Aircrew parachuting from an aircraft in distress who engage in hostile acts or attempt to evade capture, either while descending or after reaching the ground, forfeit any protection from being made the object of attack.80

14.4.3.2 Protection of Downed Aircrew at Sea. Downed aircrew at sea are generally to be regarded as shipwrecked, as the definition of shipwrecked includes forced landings at sea by or from aircraft.81 As shipwrecked persons, they must not be made the object of attack, and there are obligations to search for and collect them.82

14.4.3.3 Rescue of Downed Aircrew. The rescue of downed aircrew to prevent their capture by the adversary is generally regarded as a combat activity that enemy military forces may legitimately oppose.83 Medical personnel, ships, or aircraft engaged in the rescue of downed aircrew must not hamper or interfere with the efforts of opposing military forces to capture downed aircrew or they will forfeit protection from being made the object of attack as a result.84

The United States has understood the prohibition against the use of riot control agents as a method of warfare not to prohibit the use of riot control agents to rescue downed aircrew in certain circumstances.85

14.4.3.4 Downed Aircrew Evasion From, and Capture by, the Enemy. Downed aircrew may use enemy uniforms to evade capture by the enemy, but, in some cases, such use may risk liability to treatment as a spy.86 Likewise, downed aircrew may use civilian clothes to evade capture by the enemy.87

79 Refer to 5.10.5 (Persons Parachuting From an Aircraft in Distress). 80 Refer to 5.10.5.1 (No Hostile Acts or Attempts to Evade Capture). 81 Refer to 7.3.1.2 (Shipwrecked). 82 Refer to 7.3.3 (Meaning of Respect and Protection of the Wounded, Sick, and Shipwrecked); 7.4.1 (GWS-Sea Obligation Regarding the Search, Collection, and Affirmative Protection of the Wounded, Sick, Shipwrecked, and Dead). 83 2004 UK MANUAL 12.70.1 (The use of, for example, military assets to rescue aircrew who have been downed on territory under the control of the enemy is a combat activity. It is therefore legitimate for an enemy in such circumstances to attack the rescuers or by some other means to impede or prevent the rescue activity.). 84 Refer to 4.9.2.3 (Exclusively Engaged in Humanitarian Duties); 7.12.2.3 (No Hampering the Movement of Combatants ); 7.14.2.2 (Search, Rescue, or Other Recovery Excluded). 85 Refer to 6.16.2 (Prohibition on Use of Riot Control Agents as a Method of Warfare). 86 Refer to 5.23.1.4 (Use of Enemy Uniforms to Evade Capture or Escape). 87 Refer to 5.25.3 (Examples of Other Deceptions That Are Not Prohibited). Compare 9.25.2.2 (Only Disciplinary Punishments in Respect of an Act of Escape).

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If downed aircrew fall into the power of the enemy during international armed conflict, they are entitled to POW status.88 Downed aircrew remain entitled to POW status even if they unsuccessfully attempt to escape capture by enemy forces or if they attack enemy forces upon reaching the ground. As POWs, downed aircrew are entitled to protection from violence from the civilian population and others.89

14.4.3.5 Downed Aircrew in Neutral Territory. Military aircrew forced to land in neutral territory due to navigational failure, combat damage, mechanical failure, or other emergencies are subject to internment by the neutral State for the duration of the conflict.90

14.5 MEASURES SHORT OF ATTACK: INTERCEPTION, DIVERSION, AND CAPTURE

Interception. During armed conflict, a party may choose to intercept an aircraft 14.5.1through a variety of ways, including closing to visual range or to a distance where the target aircraft is within the range of weapons systems. Interception of civil aircraft that are not military objectives should be exercised with due regard for the safety of such aircraft.91

14.5.1.1 Purposes for Conducting Interception. Interception may have a variety of purposes, including, for example:

to assist in the obligation to distinguish between military objectives and civilian objects and the obligation to protect the civilian population,92 such as by

o warning a civil aircraft to refrain from entering an area of active operations; or

o helping identify whether the aircraft constitutes a military objective;

as part of the belligerent right of visit and search, including the belligerent right to enforce a blockade,93 such as by

o facilitating identification of an aircraft (e.g., enemy or neutral);

o forcing an aircraft to divert and land at a specific airfield for search or capture; or

to be in a position to attack the aircraft.

14.5.1.2 Airspace Where Interception May Be Conducted. As a general rule, belligerent military aircraft may not intercept aircraft in neutral airspace.94

88 Refer to 9.3 (POW Status). 89 Refer to 9.5.2.2 (Protection Against Violence by the Civilian Population or Others). 90 Refer to 15.16 (Belligerent Forces Taking Refuge in Neutral Territory). 91 Refer to 14.1.1.4 (Due Regard for the Safety of Navigation of Civil Aircraft). 92 Refer to 2.5 (Distinction). 93 Refer to 15.13 (Belligerent Right of Visit and Search of Merchant Vessels and Civil Aircraft). 94 Refer to 15.10 (Neutral Airspace).

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In addition, interception may not be conducted during passage through neutral international straits or neutral archipelagic sea lanes.95

Diversion of Aircraft. Diversion and search of civil aircraft may be conducted 14.5.2outside neutral airspace as part of the belligerent right of visit and search (e.g., to help determine whether aircraft are liable to capture for carriage of contraband or for breach of blockade).96 Interference with civil aircraft of neutral States must be justified by military necessity.

If, upon interception outside of neutral airspace, reasonable grounds exist for suspecting that the intercepted civil aircraft, its cargo, or its personnel are liable to capture,97 then it may be directed to proceed to a belligerent airfield that is both reasonably accessible and suitable for the type of aircraft involved for visit and search.98 Should such an airfield not be available, the intercepted civil aircraft may be diverted from its declared destination.99

Certain aircraft are exempt from the belligerent right to divert aircraft for purposes of visit and search: (1) neutral military aircraft; and (2) neutral civil aircraft accompanied by neutral military aircraft of the same nationality.100

14.5.2.1 Failure to Comply by Civil Aircraft. An enemy civil aircraft that persistently fails to comply with military instructions becomes a military objective subject to attack.101

Failure to comply with military instructions from intercepting aircraft does not in itself render a neutral or non-belligerent civil aircraft a military objective. However, it may provide strong evidence that the civil aircraft is in fact being used for a military or hostile purpose.

Capture of Aircraft and Goods on Board Aircraft. Enemy civil aircraft and goods 14.5.3on board such aircraft may be captured outside neutral airspace.102

95 Refer to 15.8 (Passage of Belligerent Vessels and Aircraft Through International Straits and Archipelagic Sea Lanes). 96 Refer to 15.13.4.3 (Visit and Search of Civil Aircraft by Military Aircraft). 97 Refer to 15.15.1 (Grounds for the Capture of Neutral Vessels and Aircraft). 98 Consider Commission of Jurists to Consider and Report Upon the Revision of the Rules of Warfare, General Report, Part II: Rules of Arial Warfare, art. 50, Feb. 19, 1923, reprinted in 32 AJIL SUPPLEMENT: OFFICIAL DOCUMENTS 12, 44 (1938) (Belligerent military aircraft have the right to order public non-military and private aircraft to alight in or proceed for visit and search to a suitable locality reasonably accessible. Refusal, after warning, to obey such orders to alight or to proceed to such a locality for examination exposes an aircraft to the risk of being fired upon.). 99 2007 NWP 1-14M 7.6.3 (If, upon interception outside of neutral airspace, reasonable grounds exist for suspecting that the intercepted civilian aircraft is carrying contraband cargo or that, despite its neutral markings, it is, in fact, enemy, it may be directed to proceed for visit and search to a belligerent airfield that is both reasonably accessible and suitable for the type of aircraft involved. Should such an airfield not be available, the intercepted civilian aircraft may be diverted from its declared destination.). 100 Refer to 15.13.2 (Types of Neutral Vessels and Aircraft That Are Exempt From Visit and Search). 101 Refer to 14.8.3.2 (Forfeiture of Protection From Being Made the Object of Attack During Armed Conflict).

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Any enemy State aircraft (including military, law enforcement, and customs aircraft), as public movable property, is subject to capture as war booty with ownership passing immediately to the captor government.103 Similarly, prize procedure is not used for captured enemy warships.104

Neutral civil aircraft engaged in certain activity in violation of their neutral status are liable to capture.105 Even if not liable to capture, neutral civil aircraft are subject to visit and search.106

14.6 BELLIGERENT CONTROL OF AVIATION IN THE IMMEDIATE VICINITY OF HOSTILITIES

Belligerents may prohibit or establish special restrictions upon flight activities in the immediate vicinity of hostilities to prevent such activities from jeopardizing military operations. In some cases, this right may be distinct from a belligerent States right to establish airspace zones during armed conflict.107

As with the belligerent right to control the immediate area of naval operations, this right is based on a belligerent States right to ensure the security of its forces and its right to conduct hostilities without interference from neutrals.108 However, belligerent control of aviation in the immediate vicinity of hostilities may be applicable in the national airspace of belligerents.109

14.7 AIRSPACE ZONES

During armed conflict, States may establish airspace zones and associated procedures intended to prohibit aircraft from entering or flying in designated areas, including areas in

102 Consider Commission of Jurists to Consider and Report Upon the Revision of the Rules of Warfare, General Report, Part II: Rules of Arial Warfare, art. 49, Feb. 19, 1923, reprinted in 32 AJIL SUPPLEMENT: OFFICIAL DOCUMENTS 12, 40 (1938) (Private aircraft are liable to visit and search and to capture by belligerent military aircraft.); Commission of Jurists to Consider and Report Upon the Revision of the Rules of Warfare, General Report, Part II: Rules of Arial Warfare, art. 52, Feb. 19, 1923, reprinted in 32 AJIL SUPPLEMENT: OFFICIAL DOCUMENTS 12, 45 (1938) (Enemy private aircraft are liable to capture in all circumstances.). 103 Refer to 5.17.3 (Enemy Movable Property on the Battlefield (War Booty)). Consider Commission of Jurists to Consider and Report Upon the Revision of the Rules of Warfare, General Report, Part II: Rules of Arial Warfare, art. 32, Feb. 19, 1923, reprinted in 32 AJIL SUPPLEMENT: OFFICIAL DOCUMENTS 12, 30 (1938) (Enemy public aircraft, other than those treated on the same footing as private aircraft, shall be subject to confiscation without prize proceedings.); Program on Humanitarian Policy and Conflict Research at Harvard University, Commentary on the HPCR Manual on International Law Applicable to Air and Missile Warfare, 275 (U.I.136(a)) (2010) (Enemy military, law-enforcement and customs aircraft are booty of war. Prize procedures do not apply to captured enemy military aircraft and other State aircraft, inasmuch as their ownership immediately passes to the captor government by virtue of capture.). 104 Refer to 13.4.3 (Captured Enemy Warships No Prize Procedure). 105 Refer to 15.15.1 (Grounds for the Capture of Neutral Vessels and Aircraft). 106 Refer to 15.13 (Belligerent Right of Visit and Search of Merchant Vessels and Civil Aircraft). 107 Refer to 14.7 (Airspace Zones). 108 Refer to 13.8 (Belligerent Control of the Immediate Area of Naval Operations). 109 Refer to 14.2.1.1 (National Airspace).

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international airspace. Such zones may be established for a variety of purposes, including to decrease the risk of inadvertent attack of civil or neutral aircraft, to control the scope of the conflict, or to enhance the predictability and effectiveness of ongoing operations.

The legal rules that apply to the establishment and enforcement of a zone are discussed in connection with the establishment and enforcement of maritime zones.110

In some cases, such as with Air Defense Identification Zones, the zone may be established during peacetime.111

14.8 ATTACKS AGAINST MILITARY OBJECTIVES IN THE AIR

The general rules on conducting attacks also apply to attacks against military objectives in the air.112 In general, enemy military aircraft may be made the object of attack.

Medical Aircraft. Specific rules found in the 1949 Geneva Conventions address 14.8.1the protection of aircraft that are engaged exclusively in specified medical functions.113

Protection of Persons Who Surrender or Who Are Otherwise Hors De Combat on 14.8.2Board Enemy Aircraft. The general rules on the protection of persons who are hors de combat (such as those who have been incapacitated and those who have effectively surrendered) also apply to persons on board enemy aircraft.114

Although the capture of enemy military aircraft and aircrew may be of significant intelligence value, there are often significant practical obstacles to identifying when persons on board an aircraft are hors de combat and to accepting their surrender. Despite these practical difficulties, if surrender is offered in good faith and circumstances do not preclude enforcement, then surrender must be respected.115 Persons who are conducting attacks against enemy military aircraft must assess in good faith whether surrender is offered in good faith and can feasibly be accepted based on the information that is available to them at the time.116

14.8.2.1 Difficulty in Identifying Persons on Board Aircraft as Hors De Combat. As a practical matter, it may be quite difficult to establish that persons on board enemy aircraft are hors de combat and may no longer be made the object of attack.

First, it is very difficult, if not impossible, to assess whether the enemy aircraft has actually been disabled and does not pose any threat. For example, aircraft may feign symptoms 110 Refer to 13.9 (Maritime and Airspace Zones: Exclusion, War, Operational, Warning, and Safety). 111 Refer to 14.2.4 (Air Defense Identification Zone (ADIZ)). 112 Refer to 5.5.2 (Overview of Rules in Conducting Attacks). 113 Refer to 7.14 (Military Medical Aircraft); 7.19 (Civilian Medical Aircraft). 114 Refer to 5.10 (Persons Placed Hors de Combat). 115 1976 AIR FORCE PAMPHLET 110-31 4-2d (If surrender is offered in good faith so that circumstances do not preclude enforcement, then surrender must be respected.). 116 Refer to 5.4.2 (Decisions Must Be Made in Good Faith and Based on Information Available at the Time).

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of distress to evade enemy attacks.117 Moreover, even if an aircraft has been disabled in some respects, the aircraft may not have lost its means of combat, and weapons on board the aircraft may still pose a threat.

As a practical matter, it may also be difficult for the pilot of an attacking aircraft to know when an adversary is attempting to surrender or has surrendered. Broadcasting on the international GUARD frequency (aircraft emergency frequency), rocking the aircrafts wings, lowering the landing gear, and other signals (such as the flashing of navigational lights) are sometimes cited as indications of a pilot or aircrews desire to surrender, but they are not recognized in law as signals of surrender. Consequently, absent an explicit message of offering surrender, an intention to surrender cannot be presumed from the conduct of the aircraft.

14.8.2.2 Feasibility of Accepting Surrender by Enemy Aircraft. In many circumstances, it may not be feasible to accept the surrender of enemy aircraft.118 For example, it may not be possible to enforce surrender when the engagement takes place over enemy territory.119

Attacks Against Civil Aircraft. During armed conflict, civil aircraft are generally 14.8.3considered civilian objects, but may be made the object of attack, outside neutral territory, if they constitute a military objective.

14.8.3.1 Protection of Civil Aircraft in Peacetime. Under customary international law applicable during peacetime, States have an obligation to refrain from resorting to the use of weapons against civil aircraft in flight.120 However, this obligation does not modify in any way

117 Refer to 5.25.3 (Examples of Other Deceptions That Are Not Prohibited). 118 1976 AIR FORCE PAMPHLET 110-31 4-2d (Surrenders in air combat are generally not offered. If surrender is offered, usually no way exists to enforce the surrender.). 119 2004 UK MANUAL 12.64 (Although it is forbidden to kill or wound an enemy who, having laid down his arms, or having no longer means of defence, has surrendered at discretion in air-to-air combat, surrender is usually impracticable and occurs very infrequently.); 2004 UK MANUAL 12.64.1 (In the special circumstances of air-to-air combat the continuation of an attack after an indication by the opponent of a wish to surrender is not inconsistent with the rule in paragraph 12.64, as the enemy pilot who remains in his aircraft cannot be said to have laid down his arms or to have no longer a means of defence. However, if the surrender is offered in good faith and in circumstances that do not prevent enforcement, for example, when the engagement has not taken place over enemy territory, it must be respected and accepted.). 120 See, e.g., Walter Dellinger, Assistant Attorney General, United States Assistance to Countries that Shoot Down Civil Aircraft Involved in Drug Trafficking, Jul. 14, 1994, 18 OPINIONS OF THE OFFICE OF LEGAL COUNSEL 148, 149-50 ([T]he United States argued that the Soviet Union had violated both Article 3(d) and customary international legal norms in shooting down KAL 007. We understand that the United States has not yet ratified Article 3 bis. There is, however, support for the view that the principle it announced is declaratory of customary international law.); U.N. SECURITY COUNCIL RESOLUTION 1067, U.N. Doc. S/RES/1067 (1996) (6. Condemns the use of weapons against civil aircraft in flight as being incompatible with elementary considerations of humanity, the rules of customary international law as codified in article 3 bis of the Chicago Convention, .). Consider Protocol Relating to an Amendment to the Convention on International Civil Aviation (Article 3 bis), May 10, 1984, 2122 UNTS 346-47 (The contracting States recognize that every State must refrain from resorting to the use of weapons against civil aircraft in flight and that, in case of interception, the lives of persons on board and the safety of aircraft must not be endangered. This provision shall not be interpreted as modifying in any way the rights and obligations of States set forth in the Charter of the United Nations.).

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the rights and obligations of States set forth in the Charter of the United Nations.121 Thus, a States use of force against civil aircraft in the exercise of the inherent right of self-defense would be permitted.

14.8.3.2 Forfeiture of Protection From Being Made the Object of Attack During Armed Conflict. Civil aircraft may be made the object of attack, outside neutral territory, if the aircraft constitutes a military objective.122

In particular, civil aircraft forfeit any protection from being made the object of attack if they acquire the character of enemy military aircraft by:

taking a direct part in the hostilities on the side of the enemy; or

acting in any capacity as a naval or military auxiliary to the enemys armed forces.123

In addition, enemy civil aircraft forfeit protection from being made the object of attack:124

when persistently refusing to comply with directions from intercepting aircraft;125

when flying under convoy of enemy warships or military aircraft;

when armed with systems or weapons beyond that required for self-defense against terrorism, piracy, or like threats;

when incorporated into or assisting the enemys military intelligence system;126 or

121 Consider Protocol Relating to an Amendment to the Convention on International Civil Aviation (Article 3 bis), May 10, 1984, 2122 UNTS 346-47 (The contracting States recognize that every State must refrain from resorting to the use of weapons against civil aircraft in flight and that, in case of interception, the lives of persons on board and the safety of aircraft must not be endangered. This provision shall not be interpreted as modifying in any way the rights and obligations of States set forth in the Charter of the United Nations.) (emphasis added). Compare 13.1.1 (The Law of the Sea During Armed Conflict). 122 Refer to 5.7 (Military Objectives). 123 Refer to 15.14.2.1 (Acquiring the Character of an Enemy Warship or Military Aircraft). 124 2007 NWP 1-14M 8.8 (Enemy merchant vessels and civil aircraft may be attacked and destroyed by military aircraft only under the following circumstances: 1. When persistently refusing to comply with directions from the intercepting aircraft 2. When sailing under convoy of enemy warships or military aircraft 3. When armed with systems or weapons beyond that required for self-defense against terrorism, piracy, or like threats 4. When incorporated into or assisting in any way the enemys military intelligence system 5. When acting in any capacity as a naval or military auxiliary to an enemys armed forces 6. When otherwise integrated into the enemys war-fighting or war-sustaining effort.); 1989 NWP 9 8.4 (Enemy merchant vessels and civil aircraft may be attacked and destroyed by military aircraft only under the following circumstances: 1. When refusing to comply with directions from the intercepting aircraft 2. When assisting in any way the enemys military intelligence system or acting in any capacity as auxiliaries to the enemys armed forces 3. When sailing under convoy of enemy warships, escorted by enemy military aircraft, or armed 4. When otherwise integrated into the enemys war-fighting or war-sustaining effort.). 125 Refer to 14.5.2.1 (Failure to Comply by Civil Aircraft).

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when otherwise integrated into the enemys war-fighting or war-sustaining effort.

14.8.3.3 Attack of Civilian Passenger Aircraft. If a civilian passenger aircraft constitutes a military objective and thus is liable to attack, any attack must comply with other applicable rules related to attacks.127

In particular, attacks against civilian passenger aircraft engaged in passenger service must comply with the requirement that the expected loss of life or injury to civilians, and damage to civilian objects incidental to the attack, must not be excessive in relation to the concrete and direct military advantage expected to be gained.128

14.9 AIR ATTACKS AGAINST MILITARY OBJECTIVES ON THE GROUND

The general rules on conducting attacks also apply to air attacks against military objectives on the ground.129

Prohibition Against Bombardment of Undefended Cities, Towns, and Villages. 14.9.1The aerial bombardment of towns, villages, dwellings, or buildings that are undefended is prohibited.130 The phrase by whatever means was inserted in the Hague IV Regulations to clarify that bombing attacks by air were included in this rule.131

An undefended city, town, or village in this sense is a term of art. For example, a city may only be declared undefended if it is open for immediate physical occupation by opposing military ground forces.132

Selection of Weapons in Conducting Attacks From the Air Against Ground 14.9.2Military Objectives. It may be the case that commanders will have a variety of weapons with which to conduct a potential aerial bombardment.

Certain weapons are prohibited per se, and it is specifically provided that feasible precautions be taken in connection with certain weapons.133 It must be emphasized, however, that the selection of the appropriate weapon for conducting an aerial bombardment remains primarily a military judgment rather than a legal one. In particular, there is no law of war

126 Consider Commission of Jurists to Consider and Report Upon the Revision of the Rules of Warfare, General Report, Part I: Rules for the Control of Radio in Time of War, art. 6, Feb. 19, 1923, reprinted in 32 AJIL SUPPLEMENT: OFFICIAL DOCUMENTS 2, 7-8 (1938) (1. The transmission by radio by a vessel or an aircraft, whether enemy or neutral, when on or over the high seas of military intelligence for the immediate use of a belligerent is to be deemed a hostile act and will render the vessel or aircraft liable to be fired upon.). 127 Refer to 5.5 (Rules on Conducting Assaults, Bombardments, and Other Attacks). 128 Refer to 5.12 (Proportionality in Conducting Attacks). 129 Refer to 5.5.2 (Overview of Rules in Conducting Attacks). 130 Refer to 5.15 (Undefended Cities, Towns, and Villages). 131 Refer to 5.15.2 (By Whatever Means). 132 Refer to 5.15.3 (Declaration of a City as Undefended). 133 Refer to 6.4 (Prohibited Weapons); 5.3.3.3 (Requirements to Take Precautions Regarding Specific Weapons).

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requirement to use precision-guided weapons when non-precision-guided weapons may be used in compliance with the law of war.134

Commanders have a general obligation to take feasible precautions in conducting attacks in order to reduce the risk of harm to the civilian population.135 The selection of weapons may be among the available precautions that a commander could take in order to reduce the risk of harm to the civilian population.

Protection of Enemy Ground Forces Who Are Hors de Combat. When aircrew or 14.9.3aircraft operators assess that an enemy combatant has been placed hors de combat, they must refrain from making such persons the object of attack.136

In order to place a person hors de combat, the persons surrender must be (1) genuine; (2) clear and unconditional; and (3) under circumstances where it is feasible for the opposing party to accept the surrender.137

In many cases, it would not be feasible for a party that is conducting air operations to accept the surrender of an enemy person. In some cases, however, it may be appropriate, in order to facilitate such surrender, to communicate steps for enemy units to take to communicate clearly their intention to surrender.138

14.9.3.1 Difficulty in Identifying Persons Placed Hors De Combat. The identification by aircraft of an enemy combatant on the ground placed hors de combat may pose a particular challenge. It may be difficult for aircrew or aircraft operators to determine whether an enemy combatant is dead, injured, merely taking cover, or feigning injury or surrender to avoid attack.139 On the other hand, it may be difficult for enemy combatants on the ground to 134 Refer to 5.11.3 (Selecting Weapons (Weaponeering)). 135 Refer to 5.11 (Feasible Precautions in Conducting Attacks to Reduce the Risk of Harm to Protected Persons and Objects). 136 Refer to 5.10 (Persons Placed Hors de Combat). 137 Refer to 5.10.3 (Persons Who Have Surrendered). 138 Captain M. Scott Holcomb, View from the Legal Frontlines, 4 CHICAGO JOURNAL OF INTERNATIONAL LAW 561, 566-67 (2003) (In August 2002, I met with Commander Kenneth ORourke, the Chief of Operational Law at CENTCOM, and Lieutenant Commander Gregory Bart, the Special Operations Command Central (SOCCENT) Staff Judge Advocate to develop legally supportable concepts that would achieve the commanders intent to either have Iraqi units assist Coalition forces or indicate a desire not to fight and remain in place, preferably in their barracks. Consequently, we sketched an outline for an operational plan to encourage units to capitulate. Coalition forces would contact Iraqi units through various means including leaflet drops, radio broadcasts, and surrogates who would inform the commander of his opportunity to surrender with honor and preserve his unit. Iraqi units would receive these messages shortly before the air campaign started to give them time to perform the required actions, but not so much time that they would be subject to regime reprisals. If the unit performed certain observable actions, such as forming their vehicles in a square, then Special Forces would approach the unit and offer articles of capitulation for the surrender of the unit.). 139 See SPAIGHT, AIR POWER AND WAR RIGHTS 132 (In the second world war also there were one or two instances in which ground forces showed the white flag to aircraft. Other circumstances are conceivable in which there could be no assurance that the display of a white flag was not a ruse to enable the enemy troops to escape after the immediate danger was past. In such circumstances it could he [sic] held that the airmen were under no obligation to discontinue their attack.).

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communicate clearly to aircraft that they wish genuinely to surrender unconditionally or that they have been incapacitated.

Aircrew or aircraft operators must assess in good faith whether persons have been placed hors de combat based on the information that is available to them at the time.140

14.9.3.2 Feasibility of Air Units to Accept the Surrender of Ground Forces. For a communication of surrender to place a person hors de combat, the person must make the surrender under circumstances where it is feasible for the opposing party to accept the surrender.141 For example, it must be possible for the opposing party to take that person into custody.142

In many cases, it would not be feasible for the aircraft to land and take the person into custody or for nearby ground forces to take the person into custody.143

14.10 INTERNATIONAL LAW AND WARFARE IN OUTER SPACE

Classification of Outer Space. Outer space is governed by a separate legal 14.10.1regime than that for airspace.144

140 Refer to 5.4.2 (Decisions Must Be Made in Good Faith and Based on Information Available at the Time). 141 Refer to 5.10.3.3 (Under Circumstances in Which It Is Feasible to Accept). 142 For example, FINAL REPORT ON THE PERSIAN GULF WAR 381 (During this attack, the two companies of 3/1 Attack Helicopter Battalion encountered minimal resistance in the form of T-55 tanks and BMPs, which they destroyed. The surprising aspect of this operation was that it was the first of many instances where hundreds of Iraqi soldiers ran out of their bunkers and attempted to surrender after seeing Army helicopters in their midst. Without the means to hold them, the aeroscout pilots played cowboys to the herd of Iraqi soldiers, hovering them into a tight circle until the lead ground elements of the Division's 1st Brigade arrived and secured them.); FINAL REPORT ON THE PERSIAN GULF WAR 212 (In addition to direct support of NGFS missions, UAVs also were used to gather intelligence on Faylaka Island when national sensors were not available and weather prevented aircraft reconnaissance. Over Faylaka Island, USS Wisconsins UAV recorded hundreds of Iraqi soldiers waving white flags the first-ever surrender of enemy troops to an unmanned aircraft. After the cease-fire, UAVs monitored the coastline and outlying islands in reconnaissance support of occupying Coalition forces. Because UAVs were under direct tactical control of combat forces, they could respond quickly in dynamic situations. On one occasion, USS Wisconsins UAV located two Iraqi patrol boats, which were sunk by aircraft directed to investigate.). 143 For example, 101st Airborne ROE Card, Iraq (2003), reprinted in CENTER FOR LAW AND MILITARY OPERATIONS, THE JUDGE ADVOCATE GENERALS LEGAL CENTER & SCHOOL, U.S. ARMY, I LEGAL LESSONS LEARNED FROM AFGHANISTAN AND IRAQ: MAJOR COMBAT OPERATIONS (11 SEPTEMBER 2001 - 1 MAY 2003) 315, 316 (2004) (3. Facts: An armed soldier sees you and throws his hands up to surrender. Response: Take the soldier prisoner, and treat as an EPW. (Note: aircraft are not in the position to accept surrender, in the foregoing scenario, a 101st ABD aircraft could fire upon the enemy soldier).); SPAIGHT, AIR POWER AND WAR RIGHTS 131-32 (Usually it is impossible for attacking airmen to take ground troops prisoners, and such a situation as that described by Lieut.-Col. Tennant as arising in Iraq in February, 1917, is probably more typical and normal than the cases quoted above. Lieut.-Col. Tennant describes how in the Turkish retreat towards Azizieh, after the forcing by General Maudes army of the Shumran Bend in the Tigris on 23 February, 1917, many of the waggons had hoisted the white flag, while some of the flying Turks waved in token of surrender, when the British aeroplanes attacked them with machine-guns. Flying along about 10 feet from the road I mowed down seven with one burst of machine-gun fire. In such circumstances it is impossible to recognise the white flag. To try to do so would be to sacrifice the advantage of the destruction of a routed and demoralised foe.). 144 Refer to 14.2.2 (Vertical Boundary Between Airspace and Outer Space).

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Outer space may be viewed as analogous to the high seas in certain respects.145 For example, no State may claim sovereignty over outer space.146 In addition, the space systems of all nations have rights of passage through space without interference.147

Application of International Law to Activities in Space. 14.10.2

14.10.2.1 Treaties Specifically Addressing Space Activities. The United States is a Party to certain treaties that address space activities. The Treaty on Principles Governing the Activities of States in the Exploration and Use of Outer Space, including the Moon and Other Celestial Bodies (Outer Space Treaty), imposes restrictions on certain military operations in outer space (i.e., it does not exempt military spacecraft or military space activities from its purview).148 The Outer Space Treaty provides for State responsibility for the activities of non-governmental entities in outer space, including the moon and other celestial bodies.149

Other treaties that specifically address space activities include:

Agreement on the Rescue of Astronauts, the Return of Astronauts, and the Return of Objects Launched into Outer Space;150

Convention on International Liability for Damage Caused by Space Objects;151 and

Convention on Registration of Objects Launched into Outer Space.152 145 Arthur J. Goldberg, U.S. Ambassador to the United Nations, Treaty on Outer Space: Hearings Before the Committee on Foreign Relations, U.S. Senate, 90th Congress, First Session, 63 (Mar. 13, 1967) (This is an attempt, once we leave airspace, and get to outer space, however you define the limits, this is an attempt to create in outer space the closest analogy and that is the high seas.). 146 OUTER SPACE TREATY art. II (Outer space, including the moon and other celestial bodies, is not subject to national appropriation by claim of sovereignty, by means of use or occupation, or by any other means.). 147 See, e.g., OUTER SPACE TREATY art. I (Outer space, including the moon and other celestial bodies, shall be free for exploration and use by all States without discrimination of any kind, on a basis of equality and in accordance with international law, and there shall be free access to all areas of celestial bodies.); National Space Policy of the United States of America, 3 (Jun. 28, 2010) (The United States considers the space systems of all nations to have the rights of passage through, and conduct of operations in, space without interference. Purposeful interference with space systems, including supporting infrastructure, will be considered an infringement of a nations rights.); Presidential Directive/NSC-37, National Space Policy, 1.d (May 11, 1978) (The space systems of any nation are national property and have the right of passage through and operations in space without interference. Purposeful interference with operational space systems shall be viewed as an infringement upon sovereign rights.). 148 Refer to 14.10.3 (Outer Space Treaty Restrictions on Military Activities). 149 OUTER SPACE TREATY art. VI (States Parties to the Treaty shall bear international responsibility for national activities in outer space, including the moon and other celestial bodies, whether such activities are carried on by governmental agencies or by non-governmental entities, and for assuring that national activities are carried out in conformity with the provisions set forth in the present Treaty. The activities of non-governmental entities in ou