Off-wing fleet maintenance study of a CFM56-3B turbofan engine: the propulsive engine of Boeing 737-300 civil aircraft.

Abstract

An off wing fleet maintenance study of the CFM56-3B Turbofan engine that propels the Boeing 737-300 aircraft is presented. The engine performance and deteriorating behavior was modeled with a view to estimate the creep life consumption and operating severity. The predicted severity factor of each degradation was similar to the trend observed by the maintenance, repair and overhauling (MRO) with 0 - 3.1% difference. The combine degradation severity factor of the engine operating at both saline and desert mission areas was 6.4% and 7.5% respectively when compared with compressor fouling or turbine erosion cases. The creep life obtained was 2.5% lower. Combine degradation resulted in high severity factor of 5% emission development index (EDI) and the cost of complete replacement of a damaged blade was USD 256 per flight hour (FH). However, for the isolated cases of degradation, the severity factor was 3% EDI lower and the cost of refurbishing a damage blade was USD 81/FH. This indicates that a refurbishment program can be considered for CFM56-3B engines operating in condition of low severity and replacement program for engines operating in condition of high severity.

Keywords: Turbofan engine, Severity factor, Degradation