Twelve thousand T56 turboprop engines have been delivered for commercial and military air- craft to 49 countries. The current production T56 engine is rated at 4591 shaft horsepower (SHP) on a standard 59°F day and 3695 SHP on a hot 103°F day. The Air Force with a large inventory of T56 powered C-130 aircraft is sponsoring an Engine Model Derivative Program (EMDP) to develop a cost effective T56 derivative engine with 10½% fuel consumption improvement and 24% power increase. These improvements are being achieved at low cost and low risk by utilizing only previously demonstrated component technology. The derivative engine will operate at the conservative, long life conditions of 2110°F turbine inlet temperature and 12:1 cycle pressure ratio. Existing T56 engines can be upgraded to the new configuration via a retrofit kit installed during normal engine overhaul. Investment recovery will be within four years of fleet retrofit.