Abstract
C-130 aircraft 1 is considered to be one of the most reliable military cargo aircraft. Its popularity mainly rests with military users especially with the air forces around the world. It forms the backbone for tactical and transportation operations. It is equipped with four T-56 turboprop engines to keep the transport aircraft in air. During missions the aircraft might get exposed to short runway takeoffs or landings. Engines are being stressed with both a high operation temperature and a severe short take off and landing environment. This lays high demand on its engines' reliability to continuously give outstanding performance under all such conditions with minimum or limited maintenance requirements. In this research, in depth study has been conducted on maintenance and improvement of engines on the basis of defects data collected over five years, and findings have been established from comparative analysis of these results. The results are considered reasonably important for such aircraft operators as well as maintenance crew as they provide a basis to discuss parts that regularly wear out too soon or do not perform as well, and to identify problems and develop new repairs or initiate redesigns of parts. The data may also be used for prediction of maintenance costs and system spares requirements forecasting.