Rolls-Royce said the Accelerated Mission Testing of the Series 3.5 enhancement took place over 400 hours and 1,000 cycles and proved the durability of new engine blades, vanes and other parts.
"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 Tom Hartmann, Rolls-Royce senior vice president. "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 the Series 3.5 improvements can be installed as part of conventional engine overhaul. Aircraft or engine control system modifications would not be required.