The range of sizes and types of turboprop powerplants in current commuter service are discussed. The expected growth of this transportation sector in the 80's and 90's require more efficient powerplants with better economy and fuel conservation. General Electric is conducting a Propulsion Study for NASA as part of the Small Transport Advanced Technology (STAT) program. The General Electric CT7 is used as the current modern turboprop engine baseline. Thirty- and fifty-passenger commuter aircraft were defined to illustrate the potential improvement possible with advanced turboprops. Selection studies and evaluation procedures of the cycle and advanced design features suitable for these engines are discussed.