P431, shown in Figure 14, was instrumented to validate many of the Phase II improvements:
・#4/5 and #6 Bearing Compartment Temperatures with Cold Buffer System
・#4 Bearing Thrust Load
・Combustor Temperature Exit Profile
・Turbine Transition Duct Segment Temperature
Phase II Validation Complete
Endurance testing (P411) and instrumented engine testing (P431) which began in February 1996 was completed in July 1996. Validation criteria established before the testing program was confirmed by the appropriate design engineers using data collected during testing and hardware inspections of the test engines after disassembly. The Phase II Package was fully validated and therefore ready for production release.
FT8 Current Service Experience
Commercial operating experience with of Phase II has been very good. As of 11/18/97, the two lead-the-fleet Phase II units at customer sites in Northern Ontario, Canada have accumulated 8300 hours and 7800 hours respectively. Borescope inspections and engine parameter trending continue to provide evidence that the Phase II improvements are working as designed. For example, engine breather pressure trending, which is definite measure of main shaft seal integrity, indicates a normal wear rate as shown below :
Installation of Phase II configured engines into commercial operation has had a dramatic improvement in FT8 Operational Fleet Statistics. The following is a summary of statistics to date for the Turbo Power and Marine Fleet :
FT8 Phase II Operational Statistics
Through 10/31/97
Reliability 99.5%
Availability 95.2%
Through repair shop retrofits and introduction of new engines to commercial operation, 85% of the current FT8 fleet is configured with Phase II.
SUMMARY and CONCLUSION
・The FT8 Phase II Reliability Improvement Package is based on experience gained in the initial 100,000 operating hours. By definition, the package addresses all the known causes of unscheduled removal in addition to adding durability enhancements which will result in lower repair costs over the life of the machine.
・The stringent requirements and criteria established to validate the Phase II package, required a two test engine approach. To achieve complete validation, a complete on-site "FT8 Installation" was constructed in East Hartford, Connecticut for the purpose of a rigorous endurance test. This test, combined with a heavily instrumented engine test, were used to validate Phase II improvements.
・In July of 1996, P&W Engineering confirmed complete validation of the Phase II Package. Shortly thereafter, the improvements were production ready and the retrofit of existing GG8s in the fleet commenced.
・To date, the service experience of the Phase II package has been excellent as confirmed by engine health monitoring, dramatic improvements in operational statistics, and customer feedback.
