Der Abschuss von Zivilflugzeugen als ultima ratio zur Abwehr von sogenannten Renegades aus völkerrechtlicher Sicht

On 11 September 2001, 19 terrorists overpowered the crews of four commercial passenger aircrafts. The terrorists used the aircraft to commit terrorist attacks by flying the planes into the World Trade Center and in the Pentagon. This form of terrorist attack is described as renegade. Aerial incidents in the following time illustrate that the threat of another renegade is still present. Therefore, the question is still prevailing whether the shooting down of civil aircraft in order to prevent a renegade is lawful. This article is analyzing the legality of shooting down civil aircraft from a public inter- national law perspective. In the first part of the article, it will be discussed that the shooting down of civil aircraft is a violation of the prohibition to use force against civil aircraft in flight which is codified in Article 3bis(a)(1) of the 1944 Convention on International Civil Aviation (so-called Chicago Convention). This norm is also part of customary inter- national law. It will be argued that the limitations of this prohibition, which are codified in Article 3bis(a)(2) of the Chicago Convention are inapplicable as a renegade does not con- stitute an armed attack in the meaning of Article 51 of the Charter of the United Nations – mainly because the terrorist acts cannot be attributed to another State. Limitations of the prohibition to use force against civil aircraft in flight might be also found in other provisions of the Chicago Convention. In the second part of this article, it will be shown that Article 4 of the Chicago Convention prohibits a misuse of civil aviation. Even if the terrorist acts can be attributed to another State and therefore might be consid- ered to be a misuse of civil aviation, Article 4 of the Chicago Convention does not allow the shooting down of civil aircraft. In the third part of this article, limitations of the prohibition to use force against civil aircraft in flight arising out of Article 89 of the Chicago Convention will be examined. In accordance with the findings in the first part, it will be presented that there is regularly no armed conflict, thus Article 89 (1) of the Chicago Convention is inapplicable. Even if there would be an armed conflict, international humanitarian law would still prohibit in most cases the shooting down of civil aircraft as they are regularly civil objects, thus not lawful targets of any armed activity. In addition, the requirements of a necessity are normally not fulfilled which results in an inapplicability of Article 89 (2) of the Chicago Convention. As the shooting down of civil aircraft regularly constitutes a violation of the prohibition to use force against civil aircraft in flight, it is questionable whether this violation is justifiable. The fourth part of this article presents six possible justifications which all arise out of customary international law. These justifications are self defense, countermeasure, force majeur, distress, necessity, and State practice. However, it will be shown that the criteria for each justification are not fulfilled. Therefore, the shooting down of civil aircraft in order to prevent a renegade constitutes regularly an unjustifiable violation of the prohi- bition to use force against civil aircraft in flight.