In the domain of aerospace aftermarkets, which often has long sup- ply chains that feed into the maintenance of aircraft, contracts are used to establish agreements between aircraft operators and main- tenance suppliers. However, violations at the bottom of the supply chain (part suppliers) can easily cascade to the top (aircraft oper- ators), making it difficult to determine the source of the violation, and seek to address it. In this context, we have developed a global monitoring architecture that ensures the detection of norm viola- tions and generates explanations for the origin of violations. In this paper, we describe the implementation and deployment of a global monitor in the aerospace domain and show how it generates explanations for violations within the maintenance sup- ply chain. We show how these explanations can be used not only to detect violations at runtime, but also to uncover potential problems in contracts before their deployment, thus improving them.