US Air Force Temporarily Halting Acceptance of KC-46 Aircraft from Boeing Due to Cracks in Support Structure

The US Air Force has temporarily halted the acceptance of new KC-46A aerial refueling aircraft from Boeing after cracks were discovered in two of the four planes scheduled for delivery.

The cracks were reportedly found in the “outboard fixed-trailing-edge support structure” of the aircraft, an essential component of the plane’s structural integrity.

Although the cracks do not pose an immediate safety risk, the discovery has led to concerns about the aircraft’s long-term performance and operational readiness.

This recent decision to halt the delivery is part of the ongoing scrutiny of Boeing’s KC-46 program, which has faced numerous technical challenges since its inception.

The Air Force has also announced that, as a precaution, it will inspect its entire fleet of 89 KC-46A Pegasus aircraft currently in service to ensure that similar issues are not present. Let’s take a closer look.

Details of the Crack Discovery

The cracks were found on two of the four new KC-46A aircraft that were ready for delivery to the US Air Force. These cracks were located in the “outboard fixed-trailing-edge support structure,” a part of the aircraft’s frame that is crucial for maintaining the aircraft’s stability and integrity during flight.

While the damage does not present an immediate safety hazard, it must be addressed to avoid future operational limitations, such as reduced flight durations and range.

The US Air Force spokesperson clarified that the issue does not involve the aircraft’s flight surfaces or hinges, meaning that the cracks are not directly linked to the plane’s ability to perform its primary aerial refueling mission. However, the cracks could affect the aircraft’s overall structural performance and require immediate attention.

Action Taken by Boeing and the US Air Force

Following the discovery, Boeing has taken steps to temporarily halt the delivery of the KC-46A aircraft.

The company stated, as reported by TWZ earlier this month, that it is working closely with the US Air Force to identify the root cause of the cracks and to implement a corrective action plan.

The halt in deliveries will remain in effect until the issue is fully understood and addressed, ensuring that future aircraft meet the required standards for structural integrity and performance.

The US Air Force has announced that it will inspect its existing fleet of 89 KC-46A Pegasus tankers, which have been in service since the first delivery of the aircraft in January 2019.

If any similar cracks are found during the inspection, the affected aircraft will undergo repairs before they are allowed to fly again. This proactive approach aims to prevent any operational disruptions and ensure that the KC-46A fleet remains mission-ready.

KC-46 is doomed by multiple problems, likely induced by excessive vibration, causing the failure of multiple components, like the APU door rib failures and fuel system leaks, and incidents during refueling.
But cracks in 2 out of 4 “new”planes? pic.twitter.com/OptteAExNu

— André Gonçalves Bidá (@andre_bida) March 1, 2025

Technical and Operational Challenges of the KC-46 Program

The KC-46 program has faced persistent technical difficulties from the outset.

Originally hailed as a solution to replace the aging fleet of KC-135 Stratotankers, the KC-46A Pegasus was expected to enhance the US Air Force’s aerial refueling capabilities and provide a multi-role platform capable of cargo and troop transport in addition to its refueling mission.

However, the program has been plagued by various issues, including problems with the boom, the aircraft’s primary refueling mechanism, and the Remote Vision System (RVS) used by boom operators.

The boom’s stiffness and the RVS’s limitations were particularly problematic, with the latter being found to have the potential to cause operational safety issues and even physical discomfort to operators.

The first @USAirForce #KC46 will be delivered to @22ARW #TeamMcConnell in October. The best of #Boeing are working 24/7 to ensure the Air Force gets them as quickly as possible. pic.twitter.com/3KeC1vdE1v

— Boeing Defense (@BoeingDefense) June 20, 2018

A 2024 Department of Defense report revealed that the KC-46A was not meeting key operational metrics, such as availability and mission capability rates, which were falling below the required thresholds.

The report also highlighted ongoing maintenance challenges, including delays caused by supply chain issues for necessary repair parts. These setbacks have contributed to significant delays and increased costs for Boeing and the US Air Force.

Boeing’s Financial Losses and Impact on the Program

The ongoing technical issues have also had a financial impact on Boeing. In January 2024, the company reported an $800 million loss on the KC-46 program due to higher-than-expected manufacturing costs.

This loss was further exacerbated by a production halt caused by a strike in Boeing’s Seattle-area machinist union, which delayed the production of key aircraft components.

Boeing has acknowledged that the KC-46 program has been a financial burden, and the company has lost billions of dollars since it entered into a fixed-price contract with the US government for the aircraft’s production.

Despite these challenges, the Air Force remains optimistic about the KC-46 program’s future. The service has continued to prepare for the aircraft’s eventual deployment, with several bases already selected to house the KC-46A tankers.

Conclusion

The discovery of cracks in two KC-46A aircraft has led to a temporary halt in the acceptance of new units and triggered a fleet-wide inspection of the 89 KC-46A Pegasus tankers already in service. Although the cracks do not pose an immediate safety risk, they highlight ongoing concerns with the aircraft’s structural integrity and the broader technical challenges that have plagued the KC-46 program since its inception.