Following the finding of structural flaws in two of four aircraft awaiting transfer to the US Military Delivery Centre, the United States Air Force has delayed delivery of the KC-46A Pegasus aerial refuelling aircraft.
Boeing identified the issue, prompting an inspection of the entire KC-46 fleet and production line. Consequently, deliveries to both the US and Japan have been put on hold until further evaluations are completed.
Boeing stated that if structural cracks are found in any aircraft, they will undergo a comprehensive repair programme before returning to service. According to The War Zone, the cracks are not located in flight surfaces or hinges but in primary and secondary aerostructures, raising concerns about the aircraft’s durability. Boeing issued a statement regarding the situation:
"We are working closely with our customer to assess a possible issue with the KC-46A and mitigate any impact on the fleet and production aircraft."
Previously pointing up several flaws in the KC-46A program, the 2024 Fiscal Year Defence Operational Test and Evaluation (Dote) Report With mission-capable and availability rates well below intended levels, the aircraft fell short of basic operational criteria.
Additionally, factoring in aircraft with partial mission capability due to refuelling boom malfunctions, the effective mission-capable rate was reported to be 24% lower than expected.
The KC-46A Pegasus programme has faced recurring delays and technical setbacks since its inception. Initial deliveries, originally scheduled years earlier, only began in January 2019. The aircraft has struggled with two major issues:
Refuelling Boom System Deficiencies: Boeing has been working on both hardware and software upgrades to mitigate the risk of hard contacts between the boom and the receiving aircraft.
Remote Vision System (RVS) Failures: The original RVS was deemed hazardous, with reports of it causing physical discomfort for operators. A completely redesigned version is now being integrated into the KC-46 fleet.
In March 2024, a two-month delivery delay was reported after the fracture of a component within the refuelling boom system. Inspections of the production line revealed a breakage in the gimbal nut lock wire, a critical part of boom alignment.
Financial and Strategic Affect on Boeing and the USAF
Constant problems with the KC-46A have caused Boeing great financial losses. Attributed to higher-than-expected manufacturing expenses for the Pegasus programme, the firm revealed in January 2024 a $800 million deficit for the fourth quarter. For Boeing, the fixed-price contract arrangement of the KC-46A program has caused losses of billions of dollars.
Designed to replace the old KC-135 fleet, which has been in use since the 1950s, these most recent losses provide even another obstacle to the USAF's attempts at modernising its fleet. The final KC-10 Extender's retirement in September 2023 together with ongoing reliability issues over the KC-46A have produced a significant void in US Air Force aerial refuelling capacity.
