EVALUATION OF TOTAL ENGINE PERFORMANCE DEGRADATION BASED ON MODULAR EFFICIENCIES

The current maintenance and overhaul of large civil jet engines is completely based on-condition and is widely customized to the individual requirements of the operation. Therefore, a very important factor for an effective and economic engine maintenance program is the investigation and appreciation of the current engine condition, as well as its individual deterioration mechanism. This paper is introducing a method to analyze the engine performance deterioration between two typical off-wing maintenance events (shop visits) so as to draw conclusions for maintenance planning and operation. In order to perform a precise evaluation the performance analysis is conducted on a modular level. Therefore the engine is divided into the following major modules: FAN, LPC, HPC, combustor, HPT