A Cooperative Airline Program to Evaluate Engine Parts Aging Effects on a Current Turbofan Engine Model

The contribution that aged hardware makes to performance deterioration is of interest to operators of JT3D turbofan powered aircraft since a significant percentage of these engines have exceeded 20,000 hr of operation.

Recent studies involving numerous engine disassemblies, rebuild, and test cell runs reveal the most significant effects of aged hardware are the loss in high and/or low compressor stall margin; and, that a large number of parts must be replaced to realize a significant improvement in fuel consumption, with the exception of the reduction that can be obtained by controlling turbine seal clearances.