The T56 is used on C-135 Hercules aircraft and completion of the tests will lead to military and Federal Aviation Administration certification for the enhanced power systems.
"Completion of the final element of testing has underlined the results from earlier flight tests and demonstrates continued success for the Series 3.5 for the T56 engine," said Rolls-Royce Senior Vice President Tom Hartmann. "The fuel savings of 9.7 percent, plus performance and reliability improvements, give operators exactly what they need.
"Interest from U.S. and international C-130 operators continues to grow and we look forward to U.S. Air Force qualification and FAA certification by the end of the year."
Rolls-Royce said testing demonstrated the durability of the new blades, vanes and other parts of the engine over a period of 400 hours and 1,000 cycles. Test results exceeded expectations for reduced fuel consumption and reliability.