The new approach used for the YJ101 development program has produced achievements which are applicable to future engine programs. A description is presented of the YJ101 engine as well as the unique development program leading to flight qualification. Two specific achievements are reviewed; first, the inlet-engine compatibility, and second, engine life evaluation.The inlet compatibility program established specific steps to be followed to achieve stall-free engine operation. The objectives of each step are reviewed.Realistic engine development testing is recognized as a key requirement for the engine industry. Correlation of factory testing with service usage is important to the development of a methodology for engine testing. An analysis of the actual YF-17 engine operation is made and compared to factory development testing. Further development of these concepts is required.