Section E: Military Objectives

[Commentary]


  1. Section E applies in its entirety to both international and non-international armed conflicts.
  2. Lawful targets can be attacked, subject to the applicable rules of the law of international armed conflict (such as the rules of proportionality and the requirement to take feasible precautions in attack; see respectively Section D, in particular Rule 14, and Section G). Lawful targets are defined in Rule 10 (b) as encompassing combatants; military objectives; and civilians taking a direct part in hostilities.
  3. The phrase “military objectives” originated in Art. 24 (1) of the HRAW[257] , providing that only military objectives may be attacked through air bombardment. It has been repeated in several treaty texts, pre-eminently in Art. 52 (2) of AP/I, which reiterates that “[a]ttacks shall be limited strictly to military objectives”.[258]
  4. The foundation of the principle that only lawful targets can be attacked is the principle of distinction, recognized by the ICJ in its Nuclear Weapons Advisory Opinion[259] as an “intransgressible” principle of international law and as one of two “cardinal” principles (the other being unnecessary suffering or superfluous injury) of the law of international armed conflict. The basic requirement of distinction between combatants and military objectives, on the one hand, and civilians and civilian objects, on the other hand, is stressed also in Art. 48 of AP/I.[260] Undoubtedly, it also reflects customary international law. See Rule 10 and Rule 11.
  1. Art. 24 (1) of the HRAW, see fn. 98.
  2. Art. 52 (2) of AP/I, see fn. 99.
  3. ICJ, Nuclear Weapons Advisory Opinion, paras. 78 and 79.
  4. Art. 48 of AP/I, see fn. 193.

Rule 22

In the definition of objects as military objectives (see Rule 1 (y)), the following criteria apply:

[Commentary]

(a) The “nature” of an object symbolizes its fundamental character. Examples of military objectives by nature include military aircraft (including military UAV/UCAVs); military vehicles (other than medical transport); missiles and other weapons; military equipment; military fortifications, facilities and depots; warships; ministries of defence and armaments factories.

[Commentary]

(b) Application of the “location” criterion can result in specific areas of land such as a mountain pass, a bridgehead or jungle trail becoming military objectives.

[Commentary]

(c) The “purpose” of an object although not military by nature − is concerned with the intended future use of an object.

[Commentary]

(d)  The “use” of an object relates to its present function, with the result that a civilian object can become a military objective due to its use by armed forces.

[Commentary]

  1. Subject to the other requirements of the definition (see paragraph 3 of the Commentary on the chapeau to this Rule), there are four alternative criteria qualifying an object as a military objective: nature, location, purpose or use. These four criteria are the core of the definition of military objective, and they are analyzed in some detail in the four subparagraphs of this Rule.
  2. As a practical matter, attacks are most commonly based on an object’s nature (generally the enemy’s military equipment or installations) or by use by the enemy; qualification by purpose (the enemy’s intended future use of an object) or location is less common.
  3. The definition of military objective not only requires that an object “make[s] an effective contribution to military action” “by nature, location, purpose or use”, but also that its “total or partial destruction, capture, or neutralization, in the circumstances ruling at the time, offers a definite military advantage” (see Rule 1 (y)). As indicated in paragraph 3 of the commentary to Rule 1 (y), compliance with the first criterion will generally result in the advantage required of the second.

  1. In order to qualify as a military objective by nature, the object in question must have an inherent characteristic or attribute which contributes to military action. Military equipment and facilities most clearly qualify on this basis, as do tanks, military aircraft, military airfields, or military barracks. Even when not in use, such objects always constitute lawful targets during armed conflict.
  2. As mentioned in Rule 22 (a), military objectives by nature include Ministries of Defence. This will be the case even if such Ministries are staffed in part by civilians. Of course, to the extent that a Ministry of Defence has physically separate non-defence departments, as in the case of the Swiss Federal Ministry of Defence, Civil Protection and Sport, its facilities devoted exclusively to such civilian functions are not military objectives by nature.
  3. The examples mentioned in Rule 22 (a) are non-exhaustive. Their distinctive feature is that they qualify as military objectives by nature in all circumstances. Other objects could qualify as military objectives by nature as well (see Rule 23).

“Location” relates to selected areas that have special importance to military operations, such as a particular mountain pass that may offer enemy armed forces a route of retreat in the face of a planned attack. Because of the location of the pass, it is lawful to block it through air attack, irrespective of use. Similarly, an attacker may wish to blind the enemy by depriving it of high ground from which it could observe the attacker’s operation. It may also destroy natural cover in the area, to prohibit the enemy from using it as an observation point. In these cases, it is not actual “use” or the enemy’s intended future use (“purpose”) that matters. The governing criterion is the need to attack a location so as to enhance or safeguard the attacker’s operations or to diminish the enemy’s options.

  1. It is essential to distinguish “purpose” from “use” (see Rule 22 (d)). The latter refers to present function of an object, whereas the former focuses on intended future use. The purpose criterion recognizes that an attacker need not wait until an object is actually used for military ends before being allowed to attack it as a military objective.
  2. The key issue in determining purpose is the enemy’s intent. In many cases, the enemy’s intent as to the future use of an object is clear. An example of such clarity is when reliable intelligence or other information indicates that an apartment building is being renovated with a view to serving as a military barracks. The apartment building becomes a military objective by purpose, regardless of its actual or ultimate use.
  3. Often, however, the enemy’s intent is not clear. In such circumstances, it is necessary to avoid sheer speculation and to rely on hard evidence, based perhaps on intelligence gathering. The dilemma is that intelligence is of varying degrees of reliability. The attacker must always act reasonably, i.e. as would be proper under a similar set of circumstances for any other Belligerent Party. In other words, the attacker must ask itself whether it would be reasonable to conclude that the intelligence was reliable enough to conduct the attack in light of the circumstances ruling at the time.
  4. The enemy’s intent may be based on specified preconditions prior to actual implementation of any existing plans. In such circumstances, these specified preconditions have to be fulfilled before the civilian object becomes a military objective by purpose. In other words, intelligence or other information has to lead to a reasonable conclusion that plans are in the process of being implemented, or will be implemented in the near future. Two examples can be given: (i) Communication intercepts or other intelligence may reveal that certain civilian airfields have been designated as alternative recovery airfields in the event that a military airfield is unusable. Once the military airfield is unusable, the designated alternative recovery airfields become military objectives by purpose and may be attacked, regardless of their actual or ultimate use; (ii) Overt contingency plans may exist for the use of certain civilian objects (such as civilian transports) for military airlift purposes. As long as no action is taken to activate the civilian transports for these purposes, they remain civilian objects. However, upon activation for military service, the transports in question become military objectives by purpose, regardless of their actual or ultimate use.

  1. This criterion requires actual use by the enemy of a particular object that, on the face of it, is civilian in nature. In other words, the object is not a military objective by nature, but subsequently becomes a lawful target as a result of conversion to military use.
  2. For instance, a purely civilian airfield that is subsequently used to launch or recover military aircraft loses its civilian character and becomes a military objective for the duration of its military use. Other examples would relate to (i) enemy troops billeted in a civilian hotel or school; (ii) enemy use of a civilian broadcast facility for military transmission; or (iii) civilian vehicles being commandeered by enemy forces to transport troops or materiel.
  3. In all such instances, the civilian objects become military objectives through use and may be attacked, subject to the principle of proportionality (see Rule 14) and Section G. They may not be attacked prior to such use unless there is sufficient evidence of the enemy’s intent to use the object for military ends (thereby qualifying under the purpose criterion, see Rule 22 (c)).
  4. Once use for a military purpose ceases, the object ceases to be a lawful target and may no longer be attacked. That said, if there is reliable intelligence that the enemy intends to use the object again in the future, it may remain a military objective, albeit by purpose, rather than by use. However, the mere fact that an object was used once as a military objective does not suffice, in and of itself, to establish purpose for future use.
  5. Any civilian object may become a military objective through use, including those entitled to specific protection but abused by a Belligerent Party through military use (see Sections K-N). Even objects entitled to specific protection, such as medical units (see Section K) or cultural property (see Section N (II)) can become military objectives if so used. In such a case, see Rule 32 (a) as well as Rule 35 (a) and Rule 35 (b).
  6. In case of doubt as to whether an object which is ordinarily dedicated to civilian purposes is being used for military purposes, it may only be attacked if, based on all the information reasonably available to the commander at the time, there are reasonable grounds to believe that it has become and remains a military objective (see Rule 12 (b)).
  7. Any military use of a civilian object renders it a military objective. However, the fact that it has become a military objective by use does not exclude the possibility of simultaneous civilian use. Such objects are commonly referred to as “dual-use” objects. Despite the fact that they have become a military objective, the decision whether or not they can be attacked depends by and large on the application of the principle of proportionality (see Rule 14). The classic example in the context of air or missile operations is an airport used both by military and civilian aircraft.
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Rule 23

Objects which may qualify as military objectives through the definition in Rules 1 (y) and 22 (a) include, but are not limited to, factories, lines and means of communications (such as airfields, railway lines, roads, bridges and tunnels); energy producing facilities; oil storage depots; transmission facilities and equipment.

[Commentary]

  1. The Group of Experts hesitated whether this additional list of military objectives by nature is required in light of the already existing Rule 22 (a). There were three views in the Group of Experts. One view was that all objects listed here belong in Rule 22 (a) because they are military objectives by nature at all times. The opposite view was that the objects listed in Rule 23 are not necessarily military objectives by nature, but, if at all, by use, purpose or location.[261] The majority of the Group of Experts accepted the present Rule as a compromise third view, by which military objectives by nature were to be divided into two subsets. The first, reflected in Rule 22 (a), consists of military objectives by nature at all times. By contrast, the second subset — reflected in Rule 23 — consists of objects which become military objectives by nature only in light of the circumstances ruling at the time.
  2. The reference to Rule 1 (y) in its totality is designed to stress the fact that the objects listed by way of example may not be attacked unless the criteria of Rule 1 (y) are met. However, it must be borne in mind that the list is given in the context of military objectives by nature. The focus, therefore, is on the cross-reference to Rule 22 (a). That is to say, the present Rule does not refer to Rule 22 (b) − (d). The objects listed in Rule 23, while subject to debate and some disagreement, reflect the views of the majority of the Group of Experts.
  1. According to the ICRC, there are no subsets of military objectives by nature. In its view, it has no foundation in the existing law of international armed conflict. The Commentary to Rule 22 (a) clearly indicates that an object is a military objective by nature only if it has an “inherent characteristic or attribute which contributes to military action”. An “inherent characteristic or attribute” cannot be conceived of on a merely temporary basis. By definition it has to be permanent. In the opinion of the ICRC, Rule 23 — for illustration purposes — includes categories of objects which, depending on the circumstances, may qualify as military objectives through use, purpose or location. In other words, every object falling into the categories mentioned in Rule 22 (a) is a military objective by nature, whereas the objects falling into the categories cited in Rule 23 may only under certain circumstances qualify as military objectives. For example, a factory producing weapons (see Rule 24 (a)), is a military objective by nature. A factory producing purely civilian goods is not a military objective. However, depending on use or purpose it may become a military objective. The key is that the test for military objectives set forth in Rule 1 (y) must be met before an object may be attacked.
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Rule 24

The connection between a military objective and military action may be direct or indirect.

[Commentary]

  1. As set forth in Rule 1 (y), the definition of military objectives depends in part on their making “an effective contribution to military action”. This Rule stresses that the connection between the target and ongoing military operations need not be direct. For instance, it is lawful to attack enemy military storage depots or barracks far from the battlefield because such assets constitute reserves for further military action by the enemy. It is also well-accepted that factories producing munitions and military equipment are lawful targets (see Rule 22 (a)). So too would be a port, railroad, road or airport used in the transport of supplies necessary for the production by the factory of military items (see Rule 23).
  2. There is a controversy as to whether “war-sustaining” economic objects qualify as military objectives. A war-sustaining economic object is one which indirectly but effectively supports the enemy’s overall war effort.[262] Those who subscribe to the qualification of such objects as military objectives argue that a Belligerent Party’s war-sustaining capability is directly connected to its combat operations. For instance, they contend that a Belligerent Party may lawfully attack export oil production intended for Neutrals since the profits finance the war effort. Materials of actual military value to the enemy — such as oil or petrol dedicated to military use — are not related to the argument, inasmuch as they constitute military objectives by nature. The crux of the issue is related to revenues from exports of oil which is not put to military use by the enemy. The majority of the Group of Experts took the position that the connection between revenues from such exports and military action is too remote. Consequently, it rejected the war-sustaining argument (see also paragraph 8 of the Commentary on Rule 1 (y)).
  3. The connection between the military objective and “military action” (concept which appears in the definition of military objectives, see Rule 1 (y)) must be actual and discernible, not merely hypothetical or speculative. For instance, the destruction of a civilian airfield incapable of launching military aircraft cannot be justified on the basis that the enemy might one day possess the means of launching and recovering in that airfield. Of course, if the enemy has a clear-cut intent to transform the civilian airfield into one usable for military purposes, the purpose criterion of Rule 22 (c) may turn it into a military objective by purpose.
  4. Further, the action in question must be military in nature and not, for instance, political, financial, economic or social. As an example, striking otherwise civilian targets in order to create the impression that the enemy civilian leadership is weak would not constitute an attack against a military objective which contributes to the enemy’s military action.
  1. Second subparagraph of Para. 8.2.5 of NWP (“Objects”): “Proper objects of attack also include enemy lines of communication, rail yards, bridges, rolling stock, barges, lighters, industrial installations producing war-fighting products, and power generation plants. Economic objects of the enemy that indirectly but effectively support and sustain the enemy’s war-fighting capability may also be attacked.”
Categories: E: General Rules Tags:

Rule 25

Aircraft may be the object of attack only if they constitute military objectives.

[Commentary]

  1. This Rule flows from the general rule restricting attacks to lawful targets (see Rule 10).
  2. The primary purpose of Rule 25 is to emphasize that attacks against civilian aircraft, civilian airliners, State aircraft that do not qualify as military aircraft, medical aircraft and cartel aircraft are forbidden, unless protection is lost as explained in Rule 27 (for enemy aircraft, other than military aircraft, except enemy civilian airliners); Rule 63 (for civilian airliners, enemy or neutral) and Rule 174 (for neutral civilian aircraft, except neutral civilian airliners), or the aircraft otherwise constitutes a military objective.
  3. As for military aircraft, see Rule 22 (a) and Rule 26.
  4. State aircraft, such as law-enforcement aircraft, may be armed for purposes other than military operations. They nevertheless do not constitute military objectives unless used for military purposes or incorporated into the armed forces of a belligerent (for details, see Rule 27). That said, they are subject to treatment as booty of war or to capture as prize (for details, see Section U, in particular Rule 136 (a)).
  5. Rule 25 is not limited to enemy aircraft. In particular circumstances, neutral aircraft can also become military objectives (see Rule 174 pertaining to neutral civilian aircraft, and paragraph 1 of the Commentary on the chapeau of Rule 174 pertaining to neutral State aircraft).
  6. In a non-international armed conflict, non-State organized armed groups may have aircraft at their disposal. However, such aircraft do not constitute military aircraft (see Rule 1 (x)). They are civilian aircraft, but they may be attacked because of their use for military purposes. See paragraph 8 of the Commentary on Rule 1 (x) and paragraph 7 of the Commentary on Rule 17 (a).

Rule 26

All enemy military aircraft constitute military objectives, unless protected under Section L of this Manual, or as otherwise agreed by the Belligerent Parties under Section N (V).

[Commentary]

  1. The language of this Rule, which is based on customary international law, is derived from Para. 12.39 of the UK Manual.[263]
  2. The term “military aircraft” is defined in Rule 1 (x). Military aircraft must be marked as such. The failure to mark properly an aircraft precludes qualification as a “military aircraft” and, therefore, such aircraft may not exercise belligerent rights. However, if used for military purposes, any aircraft would nevertheless qualify as a military objective through use (see Rule 22 (d)).
  3. All military aircraft, as defined in Rule 1(x), constitute military objectives by nature at all times (see Rule 22 (a)). Military aircraft need not be armed. They can be used as tanker aircraft and they may even be dedicated to transporting civilian officials, monitoring weather, or performing scientific research. All these aircraft are military objectives by nature, irrespective of use.
  4. Because military aircraft can travel great distances in a short period of time, they are generally available for use throughout a theatre of operations. As a result, their destruction, damage or neutralization will always offer a military advantage to an attacker because it deprives the enemy of their subsequent use, and they will therefore constitute military objectives by nature at all times (see Rule 22 (a)).
  5. Military aircraft which have clearly communicated an intention to surrender may not be attacked (see Section S).
  6. Military aircraft may be granted safe conduct as cartel aircraft (see definition in Rule 1 (g) and substantive Rules in Section J (II) and J (III)).
  7. Military aircraft may constitute medical aircraft, which are subject to a different legal regime. See the definition of medical aircraft in Rule 1 (u) and Section L.
  8. During non-international armed conflicts, similarly to international armed conflicts, it is a violation of the law of armed conflict for either side to attack aircraft that do not qualify as military objectives. Law-enforcement agencies may use State aircraft for purposes unrelated to the conflict. In such cases, an attack on them would violate the law of armed conflict. However, if such aircraft fulfil the criteria that render them a military objective and are being used for purposes related to the armed conflict, an attack on them by the non-State organized armed group does not violate the law of armed conflict, although it will violate the domestic law of the State in which the conflict is occurring.
  1. Para. 12.39 of the UK Manual: “Unless they are exempt from attack under paragraphs 13.33 or 12.29, enemy warships and military aircraft and enemy auxiliary vessels and aircraft are military objectives.”

Rule 27

Without prejudice to Sections I, J and L of this Manual, the following activities may render any other enemy aircraft a military objective:

[Commentary]

(a) Engaging in hostile actions in support of the enemy, e.g. intercepting or attacking other aircraft; attacking persons or objects on land or sea; being used as a means of attack; engaging in electronic warfare; or providing targeting information to enemy forces.

[Commentary]

(b) Facilitating the military actions of the enemy’s armed forces, e.g., transporting troops, carrying military materials, or refuelling military aircraft.

[Commentary]

(c) Being incorporated into or assisting the enemy’s intelligence gathering system, e.g., engaging in reconnaissance, early warning, surveillance or command, control and communications missions.

[Commentary]

(d) Refusing to comply with the orders of military authorities, including instructions for landing, inspection and possible capture, or clearly resisting interception.

[Commentary]

(e) Otherwise making an effective contribution to military action.

[Commentary]

  1. This Rule is based on the SRM/ACS.[264] See also Para. 8.8 of NWP[265] and Paras. 12.36 and 12.37 of the UK Manual.[266]
  2. The crux of Rule 27 is qualification as a military objective. In this regard, it is not necessary that the aircraft in question be conducting an attack (see Rule 1 (e)). Instead, it need only be making an effective contribution to the enemy’s military action and its destruction, capture or neutralization would yield a definite military advantage in the circumstances ruling at the time (see Rule 1 (y)). For instance, a State aircraft — not qualifying as a military aircraft — passively gathering intelligence or conducting electronic warfare that merely interferes with enemy communications is not “attacking” but its actions still render it a military objective.
  3. Any attack on such aircraft must comply with all elements of Section D (see especially Rule 14) and Section G, in particular Section G (III) pertaining to specifics of attacks directed against aircraft in the air.
  4. While all enemy aircraft other than enemy military aircraft may lose their protection, it needs to be stressed that civilian aircraft, medical aircraft, civilian airliners and aircraft granted safe conduct do not lose their protection unless certain conditions are met. These conditions are set out, respectively, in Section I, Section L, and Section J.
  5. The following activities relate both to intended future use (“purpose”) and to “use”, and are therefore subject to the application of Rule 22 (c) and 22 (d).
  6. Rule 27 does not apply to civilian airliners, which are dealt with in Rule 63.
  7. For enemy civilian aircraft, see also Rule 50.
  8. Rule 27 applies only to enemy aircraft. Neutral civilian aircraft are dealt with in Rule 174.
  1. Para. 63 of the SRM/ACS: “The following activities may render enemy civil aircraft military objectives: (a) engaging in acts of war on behalf of the enemy, e.g., laying mines, minesweeping, laying or monitoring acoustic sensors, engaging in electronic warfare, intercepting or attacking other civil aircraft, or providing targeting information to enemy forces; (b) acting as an auxiliary aircraft to an enemy’s armed forces, e.g., transporting troops or military cargo, or refuelling military aircraft; (c) being incorporated into or assisting the enemy’s intelligence-gathering system, e.g., engaging in reconnaissance, early warning, surveillance, or command, control and communications missions; (d) flying under the protection of accompanying enemy warships or military aircraft; (e) refusing an order to identify itself, divert from its track, or proceed for visit and search to a belligerent airfield that is safe for the type of aircraft involved and reasonably accessible, or operating fire control equipment that could reasonably be construed to be part of an aircraft weapon system, or on being intercepted clearly manoeuvring to attack the intercepting belligerent military aircraft; (f) being armed with air-to-air or air-to-surface weapons; or (g) otherwise making an effective contribution to military action.”
  2. Para. 8.8 of NWP (“Air Warfare at Sea”): “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 enemy’s military intelligence system; 5. When acting in any capacity as a naval or military auxiliary to an enemy’s armed forces; 6. When otherwise integrated into the enemy’s war-fighting or war-sustaining effort.”
  3. Para. 12.36 of the UK Manual: “Enemy civil aircraft may only be attacked if they meet the definition of a military objective in paragraph 5.4.1.”
    Para. 12.37 of the UK Manual: “The following activities may render enemy civil aircraft military objectives: (a) engaging in acts of war on behalf of the enemy, eg, laying mines, minesweeping, laying or monitoring sensors, engaging in electronic warfare, intercepting or attacking other civil aircraft, or providing targeting information to enemy forces; (b) acting as an auxiliary aircraft to an enemy’s armed forces, eg, transporting troops or military cargo, or refuelling military aircraft; (c) being incorporated into or assisting the enemy’s intelligence gathering system, eg, engaging in reconnaissance, early warning, surveillance, or command, control, and communication missions; (d) flying under the protection of accompanying enemy warships or military aircraft; (e) refusing an order to identify itself, divert from its track, or proceed for visit and search to a belligerent aircraft that is safe for the type of aircraft involved and reasonably accessible, or operating fire control equipment that could reasonably be construed to be part of an aircraft weapon system, or on being intercepted clearly manoeuvring to attack the intercepting belligerent military aircraft; (f) being armed with air-to-air or air-to-surface weapons; or (g) otherwise making an effective contribution to military action.”

  1. Rule 27 (a) sets forth the most definitive example of aircraft becoming military objectives through purpose or use (see Rule 22 (c) and on 22 (d)).
  2. The phrase “hostile actions” refers to actions that typically are conducted by military aircraft during, and in connection with, hostilities. Such activities are not limited to attacks, but would also include, for instance, intelligence gathering, surveillance and reconnaissance activities.
  3. “Hostile actions” need not be directed against the military forces or assets. As long as there is a nexus to the armed conflict, such acts are liable to be committed against civilians, the civilian population or even objects within one’s own territory, regardless of whether the object is of a military or civilian nature or whether the action is lawful or not.
  4. The phrase “in support of the enemy” is included to emphasize that there must be a nexus with the conflict, in other words, that the act in question must be intended to benefit the enemy. This criterion would distinguish a hostile action from a purely criminal act.
  5. “Targeting information” is any information that enables an attack to be conducted. Examples include information pertaining to the location of the target, target area defences, description of the target area, and identification of reference points that identify the target. The acquisition and transmission of targeting information may be carried out by civilian aircraft with sensors used for civilian purposes (such as search-and-rescue aircraft equipped with infrared sensors) or may simply involve passing information as to what the aircrews observe. Such activities will constitute a hostile action in support of the enemy.
  6. It is not necessary that the enemy directed or even invited or endorsed the act in question to occur. What counts is the intent of the actor engaging in it, together with the fact that the act is of a nature to support the enemy, which determines whether a nexus to the armed conflict is present.
  7. The reference to aircraft “used as a means of attack” is specifically included to cover a situation where a civilian aircraft is flown into the intended target. In such cases, the aircraft effectively becomes a means of warfare, that is, a weapon. Military aircraft used for this purpose, such as those employed in the Japanese Kamikaze attacks of WWII, already qualify as military objectives by nature. As for (hijacked) civilian airliners, see Rule 63.
  8. The use of any aircraft other than a military aircraft as a means of attack is prohibited at all times, see Rule 115 (b).
  9. State aircraft that are not military aircraft are not entitled to exercise belligerent rights (such as conducting attacks) (see Rule 17) and, as a rule, are not military objectives by nature. However, when under the exclusive control of the armed forces and being used for military purposes, such aircraft qualify as military objectives under Rule 27 (a) or under Rule (b). Hence, they may be attacked for so long as they are so used.
  10. Rule 27 (a) applies also in non-international armed conflict.

  1. The examples set forth in Rule 27 (b) are merely illustrative. For instance, being armed with air-to-air or air-to-surface missiles exposes any aircraft to attack because there are no civilian purposes attendant to such arming. In every case, the essential inquiry is whether the aircraft in question has become a military objective through use or purpose.
  2. Rule 27 (b) is included to make clear that aircraft need not be engaging in “attacks” to qualify as a military objective. The requirement is that their actions make an effective contribution to the enemy’s military actions. The phrase “military actions” has been intentionally employed to exclude activities that are more general in character, e.g., general support to the enemy’s war effort. An example of facilitation of military action will be the carrying of ammunition for use by military units. The key is that a clear nexus exists between the flight and military actions of the enemy.
  3. Rule 27 (b) applies also in non-international armed conflict.

  1. Rule 27 (c) is based on the second sentence of Art. 16 of the HRAW.[267]
  2. “Incorporat[ion]” means that the aircraft is an integrated part of the enemy’s intelligence gathering system. This could for instance occur if an aircraft the primary function of which is environmental monitoring of the EEZ, routinely reports the presence of foreign warships, thus relieving the workload of military maritime patrol aircraft. The essence of incorporation is that the activity in question is regular or systematic and the enemy relies on the information provided in calculating its actions, thereby relieving it of the need to gather such information itself. “Assisting” means providing assistance to the enemy without necessarily being an integrated part of its intelligence gathering-system.
  3. Rule 27 (c) differs from that set forth in Rule 27 (a) regarding the provision of targeting information. In Rule 27 (c), the intent is to address activities that are integrated into the enemy’s intelligence gathering system (incorporation) or in which the armed forces obtain assistance for a particular operation (assistance), as distinct from those in which the aircraft merely happens to acquire information that it then passes on to the military which uses it for targeting purposes. In other words, Rule 27 (a) refers to incidental provision of such information, whereas Rule 27 (c) addresses planned activities.
  4. The characterization of an activity as intelligence gathering must be made carefully. Information acquired in the course of normal flights operated by other than military aircraft may be of value to enemy forces. For instance, information regarding weather, the proximity of other aircraft, and communications with other aircraft or ground control may all be militarily useful. However, reporting such information through normal aviation channels, even if it ends up in the hands of the military, does not constitute intelligence gathering. Intelligence gathering is limited to the intentional collection of information for military purposes.
  5. Rule 27 (c) applies also in non-international armed conflict.
  1. Art. 16 of the HRAW, see fn. 246.

  1. Rule 27 (d) is reflective of Para. 62 (e) of the SRM/ACS.[268] It addresses the situation where military forces encounter an enemy aircraft other than a military aircraft that is not clearly engaging in activities qualifying it as a military objective. When this situation occurs, the military forces are entitled to order that aircraft to identify itself and its activities. If necessary, the aircraft can be ordered to land for inspection (see Rule 134). In certain situations (see Section U (I)), the aircraft may be captured as prize. It may also be diverted from the area of military operations. Refusal to comply with orders to land or clearly resisting interception may render the aircraft a military objective.
  2. When an enemy aircraft other than a military aircraft is “escorted” by enemy military aircraft or warships, in either international airspace or the airspace of Belligerent Parties, they will be presumed to refuse to comply with the orders of military authorities.[269] The presumption is rebuttable because the attendant circumstances may indicate to an attacker that the escorted aircraft will in fact comply. For instance, the flight commander may communicate to an intercepting aircraft his intention to comply. Of course, the escorting military aircraft or warships are military objectives by nature.
  1. Para. 62 (e) of SRM/ACS: “Enemy civil aircraft may only be attacked if they meet the definition of a military objective in paragraph 40: … (e) refusing an order to identify itself, divert from its track, or proceed for visit and search to a belligerent airfield that is safe for the type of aircraft involved and reasonably accessible, or operating fire control equipment that could reasonably be construed to be part of an aircraft weapon system, or on being intercepted clearly manoeuvring to attack the intercepting belligerent military aircraft.”
  2. Para. 63.3 of the Commentary on the SRM/ACS: “Subparagraph (d) is similar to paragraph 60 (d) which includes sailing under convoy of enemy warships or military aircraft, an activity that may render an enemy merchant vessel a military objective. An enemy civil aircraft that flies under the protection of accompanying enemy warships or military aircraft places itself at risk in the immediate area of hostilities since the enemy warships or military aircraft are military objectives. Belligerent forces might assume that the protected enemy civil aircraft is acting as an auxiliary aircraft to the enemy’s armed forces, or, in pressing an attack, belligerent forces may misidentify the enemy civil aircraft.”

  1. This is a “catch-all” provision designed to emphasize that the activities which render an enemy aircraft other than a military aircraft subject to attack are not necessarily limited to the examples given in Rule 27 (a)–(d).
  2. The key is (intending to) engaging in any activity that would meet the criteria set forth for a military objective, i.e. (i) making an effective contribution to the enemy’s military action; and (ii) its destruction, capture or neutralization would yield a definite military advantage for the attacker in the circumstances ruling at the time (see Rule 1 (y) and Rule 22).