This poster analyzes the configuration selection process for the Cedar Island Aviation Company CIAC-1, a modern 9-passenger, twin-engine turboprop STOL aircraft developed to replace legacy commuter aircraft such as the Cessna 402C and Tecnam P2012 in Cape Air’s fleet. The main objective of this study us to identify a configuration that maximizes performance, safety, maintainability, while reducing acquisition and operating cost. Several configurations were evaluated using a decision matrix that considered short field performance, certification, aerodynamic efficiency, safety, etc. After trade studies and further analysis, a high wing, multi-engine with conventional tail layout and retractable gear was selected for its overall stability, and STOL performance. It is powered by two P&W PT6a-114A turboprops, chosen for reliability and align with Cape Air’s fleet. Aerodynamic design employs a NACA 23012 airfoil. This configuration stablishes a foundation for design iterations, including reducing tail geometry, wing placement, and stability refinement.