The security of civil aviation, likemany human activities, is regulated by a series of international standards and recommended practices. The quality of these documents is a prerequisite to reach an acceptable security level. The EDEMOI project aims at investigating different techniques to analyse these standards. The techniques that we have used, such as Requirements Engineering (RE) and formal methods, have been fruitfully tried and tested in computer science. During the first step of the project, properties were extracted from standards written in natural language and a conceptual model of the underlying system was elaborated. Since none of the existing requirements engineering methods were able to consider the specifics of our project, we turned to situational method engineering, and have defined a new RE method based on this approach. The standard considered in the article is Annex 17 of the Convention of the International Civil Aviation Organization (ICAO). We present several adaptations/extensions to relevant RE techniques necessary to take into account the specific features of our project. Finally, we describe how we have applied this new method to the analysis of Annex 17.