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WASHINGTON — The Air Force and engine builder Pratt & Whitney have completed a $21 million, fleet-wide retrofit effort for the F-22 Raptor’s dual F119 engines, after identifying what the Air Force told Breaking Defense was a fatigue issue with turbine blades that led to seven class A mishaps, nearly $23 million in damages but no operational interruption.
Brian Brackens, a spokesperson for the Air Force’s Life Cycle Management Center, said that the retrofit was prompted by “[a] low cycle fatigue defect in the 2nd stage Low Pressure Turbine Blades.”
Pratt F119 Engine Program Director Julie Ireland said in a statement that “[o]nce root causes had been identified, P&W and the USAF aligned on a corrective action plan, which involved implementing an interim over inspection of production 2nd Stage Turbine Blades while simultaneously making a change in the production process for this part. In pursuing both paths, the issue was eliminated in record time and the fleet was refreshed with inspected and/or updated blades.”
While that statement highlighted a close partnership between the contractor and the Air Force, neither could agree on exactly when the retrofits were completed. A spokesperson for Pratt indicated that the retrofits completed ahead of schedule in December 2022, but Brackens told Breaking Defense, “All field installed and serviceable spares assets were completed by May 2023.”
Pratt previously said that environmental factors prioritized certain engines for the retrofit after the root cause was identified in 2017, though the underlying environmental conditions were not specified, according to a report by Inside Defense. The retrofit effort commenced in 2019.
Ireland explained that the “F119 2nd stage turbine blades extract energy from the high temperature/high pressure combustor gas. This energy is transmitted to the front compressors and provides thrust through the nozzle.”
The fix extended to the engines of all Raptors in the Air Force’s fleet, a spokesperson for the service’s Air Combat Command said in a statement, including those for the Block 20 jets whose retirements could be blocked by lawmakers.
The first class A mishap — the Pentagon’s highest accident classification — stemming from a problem with the turbine blades was logged in 2012, with the final one occurring in 2020, according to data from the Air Force Safety Center [PDF]. (An Air Force official previously said all seven mishaps resulted from the failure of the same component, but that the root cause of its failure was different between the first mishap in 2012 and one later logged in 2017. The new hardware introduced by the retrofit corrects for all previous failures.)
Brackens said about $21 million was spent to carry out the retrofits, which occurred in the field and during scheduled depot visits, and that regular flight operations were not impacted by the issue. No injuries resulted from the mishaps.
“We are very proud of the Pratt & Whitney F119 team’s proactive response and close collaboration with the U.S. Air Force in successfully resolving the Low Pressure Turbine Blade incident. The whole effort is a great example of the diligent, active management that sustains the world-class safety, reliability, and readiness levels that the 5th generation F119 engine provides for the U.S. Air Force,” Chris Johnson, Pratt vice president of fighter and mobility programs, said in a statement.
“Throughout all steps of the process — investigation, inspection, material testing, manufacturing, delivery, and installation — there was an extraordinary teaming effort across the enterprise that enabled the program to quickly identify and implement a solution throughout the fleet in record time. In fact, F119 engine availability was maintained above USAF’s target readiness levels throughout the three-year retrofit program,” Johnson added.
A fifth-generation stealth fighter that precedes the F-35, the Raptor has been praised for the ability of its engines to push the aircraft at supersonic speeds without using its afterburners, often called supercruise. Some 183 Raptors are currently in the Air Force’s inventory, according to a service factsheet. They are set to be replaced with the sixth-gen Next Generation Air Dominance fighter whose contract award is expected next year.
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