Subject to Rule 68, activities such as any of the following may render a civilian airliner a military objective:
(a) Being on the ground in a military airfield of the enemy in circumstances which make that aircraft a military objective.
(b) 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.
(c) Facilitating the military actions of the enemy’s armed forces, e.g. transporting troops, carrying military materials, or refuelling military aircraft.
(d) 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.
(e) Refusing to comply with the orders of military authorities, including instructions for landing, inspection and possible capture, or clearly resisting interception.
(f) Otherwise making an effective contribution to military action.
- Rule 63 is partially based on Para. 56 of the SRM/ACS and on Para. 12.31 of the UK Manual.
- Rule 63 sets out the circumstances under which a civilian airliner may constitute a military objective. The term “may” indicates that, even in the circumstances described in Rule 63 (a) − (f), a civilian airliner does not automatically become a military objective. On the other hand, Rule 63 (a) − (f) does not provide an exhaustive list of the activities that may render a civilian airliner a military objective. This is indicated by the words “such as” in the chapeau of Rule 63, as well as by the open-ended nature of Rule 63 (f).
- Rule 63 (a)–(f) is merely meant to give guidance as to how to apply the definition of military objectives (see Rule 1 (y) and Section E, especially Rule 22) to civilian airliners. The activities enumerated in Rule 63 (a)–(f) relate only to “use” and “purpose” (i.e. “intended future use”), and are subject to the application of Rule 22 (c) or Rule 22 (d).
- Even if a civilian airliner has become a military objective, this does not automatically mean that it may be attacked. In addition to a civilian airliner having become a military objective, the conditions in Rule 68 must be met too before it may be attacked. Moreover, a civilian airliner which has become a military objective re-gains its civilian status once it ceases to make an effective contribution to military action.
- Rule 63 must be read against the background of Rule 27 pertaining to attacks against enemy aircraft other than military aircraft. Rule 63 (b)–(f) are textually identical to Rule 27 (a)–(e). It is only Rule 63 (a) which is specific to civilian airliners.
- The use of any aircraft other than a military aircraft as means of attack is prohibited at all times (see Rule 115 (b)).
- The main conditions precedent to an attack against a civilian airliner that has lost its protection are enumerated in Rule 68. It must be recalled however that there are also ancillary conditions in Rule 69 and 70.
- Rule 63 applies also in non-international armed conflict.
- Rule 63 (a) applies only to civilian airliners parked “on the ground in a military airfield of the enemy”. If a civilian airliner is parked on the ground in a civilian airport, Rule 59 applies.
- A civilian airliner parked “on the ground in a military airfield of the enemy” does not automatically become a military objective. In order for it to become a military objective, a civilian airliner must by its nature, location, purpose or use make an effective contribution to military action and its total or partial destruction, capture or neutralization, in the circumstances ruling at the time, must offer a definite military advantage (See Rule 1 (y) and Rule 22).
- The presence of a civilian airliner may not be abused by the enemy in order to render a military airfield immune from attack (see Rule 45). A civilian airliner present in a military airfield runs the risk of being destroyed as collateral damage, in case of a lawful attack against the airfield.
- In case that a civilian airliner (carrying civilian passengers, see the definition in Rule 1 (i)) is landing in distress in a military airfield, the prevailing view among the Group of Expert was that (i) efforts must be made to alert the enemy to the situation; and (ii) the pilot must take every measure available to him to show that the airliner is in fact in distress (open slides, etc.).
- If a civilian airliner is being diverted to a military airfield, the Belligerent Party responsible for the diversion has an obligation to remove the civilian airliner from its military airfield as soon as possible, in order not to endanger it unnecessarily.
Rule 63 (b) specifically includes the situation where a civilian airliner is hijacked and is flown into a target. In such cases, the civilian airliner effectively becomes a means of attack, that is, a weapon (see also Commentary on Rule 27 (a)).
See Commentary on Rule 27 (b).
See Commentary on Rule 27(c).
See Commentary on Rule 27(d).
See Commentary on Rule 27 (e). In case of doubt as to whether a civilian airliner is making an effective contribution to military action, Rule 59 provides for a rebuttable presumption that this is not the case.