AADL is an architecture description language intended for model-based engineering of high-integrity distributed systems. The AADL Behavior Annex (AADL-BA) is an extension allowing the refinement of behavioral aspects described through an AADL architectural description. When implementing Distributed Real-time Embedded system (DRE), fault tolerance concerns are integrated by applying replication patterns. We considered a simplified design of the primary backup replication pattern as a running example to analyze the modeling capabilities of AADL and its annex. Our contribution lies in the identification of the drawbacks and benefits of this modeling language for accurate description of the synchronization mechanisms integrated in this example.