"Although the importance of scenarios in modeling and simulation has long been well known, there still exists a lack of common understanding and standardized practices in simulation scenario development. This paper proposes a Domain-Specific Language (DLS) to provide a standard scenario specification that will lead to a common mechanism for verifying and executing aviation scenarios, effective sharing of scenarios among various simulation environments, improve the consistency among different simulators and simulations, and even enable the reuse of scenario specifications. Following DSL design practices, the proposed Aviation Scenario Definition Language (ASDL) will provide a well-structured definition language to formally specify complete aircraft landing scenarios. In order to capture the necessary constructs for a simulation scenario, Simulation Interoperability Standards Organization (SISO) Base Object Model (BOM) is adopted as the baseline metamodel. This baseline is extended using the fundamentals of aircraft landing that cover all the domain-related concepts and terminology as constructs. By taking a formal approach in defining aviation scenarios, ASDL aims at providing consistency and completeness checking, and model-to-text transformations capabilities for various targets in the aviation scenario definition domain. The results of this work will be used to develop a graphical modeling environment and automatic means to transform scenario models into executable scenario scripts. The work presented here is the first stepping stone in formal scenario definition in aviation domain."--From the paper.