Соответствующая норма
Practice Relating to Rule 29. Medical Transports
At the CDDH, Japan stated: “Flying over enemy occupied areas was still prohibited … if [it] occurred by force of urgent necessity, in the absence of an agreement, that constituted a violation of the Protocol.” 
Japan, Statement at the CDDH, Official Records, Vol. XI, CDDH/II/SR.47, 5 April 1975, pp. 528–529, § 22.