‘Treatment of old heart diseases’ was carried out at US F-22

The F-22 Raptor’s dual F119 engines have undergone a comprehensive $21 million overhaul. This retrofit operation, a joint effort by the Air Force and engine manufacturer Pratt & Whitney, was necessitated by a fatigue issue with the turbine blades. Despite causing seven class A mishaps and nearly $23 million in damages, the issue did not disrupt operations, according to Breaking Defense. 

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As explained by Brian Brackens from the Air Force’s Life Cycle Management Center, a “low cycle fatigue defect in the 2nd stage Low-Pressure Turbine Blades” was the primary reason for the retrofit. This fault was discovered in the engine’s core components and required immediate attention. 

Julie Ireland, Pratt F119 Engine Program Director, detailed how the problem was addressed. She stated that “upon diagnosing the root causes, P&W and the USAF agreed on a corrective action plan, which involved an interim over inspection of production 2nd Stage Turbine Blades while simultaneously overhauling the production process for this part.” She emphasized that these proactive measures effectively resolved the issue in record time and ensured the fleet was equipped with inspected or updated blades. 

Despite the successful collaboration between the Air Force and the contractor, there seems to be a discrepancy regarding the completion date of the retrofit project. While Pratt’s spokesperson claimed the retrofits were finished ahead of schedule in December 2022, Brackens told Breaking Defense that the task was fully completed by May 2023. 

Pratt had previously pointed out that specific engines were prioritized for retrofit due to environmental factors after the root cause was identified in 2017. However, the actual environmental conditions that led to this decision were not explicitly mentioned, as per a report by Inside Defense. The retrofit operation officially started in 2019. 

Ireland further explained the role and function of the “F119 2nd stage turbine blades”. These blades extract energy from the high-temperature/high-pressure combustor gas, transmitting this energy to the front compressors to generate thrust through the nozzle.

All Raptor engines in the Air Force’s fleet, including those for the Block 20 jets, have undergone a significant fix, according to a spokesperson for the Air Combat Command. This even extends to those planes that lawmakers may prevent from retirement. 

The issue with the turbine blades, a problem classified as a class A mishap by the Pentagon, was first noted in 2012. The most recent incident was recorded in 2020, based on Air Force Safety Center data [PDF]. An Air Force official clarified that although the seven mishaps were caused by the failure of the same component, the root cause of the failure varied between the first incident in 2012 and a later incident in 2015. Fortunately, the newly introduced retrofit hardware addresses all previous failures. 

The retrofit process, which took place in the field and during scheduled depot visits, cost roughly $21 million, said Brackens. He emphasized that the issue did not affect regular flight operations and that there were no injuries from the mishaps. 

Chris Johnson, Pratt’s vice president of fighter and mobility programs, expressed pride in the Pratt & Whitney F119 team’s proactive response. He lauded their effective collaboration with the U.S. Air Force in resolving the Low-Pressure Turbine Blade incident. “The entire effort exemplifies the meticulous, active management necessary to maintain the world-class safety, reliability, and readiness levels that the 5th generation F119 engine provides for the U.S. Air Force,” he stated. 

Johnson further praised the extraordinary teamwork demonstrated at every stage of the process. From investigation to installation, the program quickly identified and implemented a solution across the fleet in record time. “Throughout the three-year retrofit program, the F119 engine availability remained above the USAF’s target readiness levels,” he added. 

The Raptor, a fifth-generation stealth fighter that leads the F-35, has earned a commendation for its engine’s capacity to propel the aircraft to supersonic speeds without the need for afterburners, an ability known as supercruise. Around 183 Raptors are currently part of the Air Force’s inventory, as per a service factsheet. These are scheduled for replacement with the sixth-gen Next Generation Air Dominance fighter, with the contract award anticipated next year.

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