Why Did the U.S. Air Force Choose the Boeing 767 Over the C-17 for its Refueling Tanker Program?

When the U.S. Air Force was selecting a platform for its KC-46 Pegasus refueling tanker, it made a conscious decision to choose the Boeing 767 over the C-17 Globemaster III. This choice was driven by a variety of factors, including mission requirements, size and capacity, cost and development, operational flexibility, and existing fleet logistics.

Mission Requirements

The primary role of the KC-46 is aerial refueling, which requires a different design focus than the C-17, which is primarily a cargo aircraft. The 767 has a fuselage design that is more suitable for incorporating refueling systems and equipment. This aspect of the design flexibility and integration of avionics and fuel systems is crucial for the success of the tanker mission.

Size and Capacity

While the C-17 has a larger cargo capacity, the 767's size is more appropriate for the refueling mission. It allows for a balance between fuel capacity and operational flexibility, as the 767 can carry a substantial amount of fuel while still being efficient and maneuverable. The balance between cargo and fuel capacity is essential for maximizing the range and utility of the tanker.

Cost and Development

The KC-46 program was developed as a derivative of the 767 commercial airliner, which allowed for a faster and more cost-effective development process. Using a commercial platform like the 767 reduces development risks and leverages existing technology and production lines. This cost-effectiveness is a significant factor in the overall efficiency of the program.

Operational Flexibility

The 767 is designed for a variety of roles, including passenger and cargo transport, which provides the Air Force with greater operational versatility. The C-17, while capable of multiple missions, is optimized for heavy lift and strategic airlift rather than refueling. The ability to switch between different roles can be advantageous in different deployment scenarios, making the 767 a more multifunctional asset.

Existing Fleet and Logistics

The Air Force already operates a fleet of tanker aircraft based on commercial designs, such as the KC-135, which makes it easier to maintain and integrate a new tanker platform. KC-46 into existing logistics and operational frameworks. The familiarity and interoperability with existing aircraft can significantly reduce logistical challenges and training requirements.

The Role of Commercial Designs

The choice of the 767 as the platform for the KC-46 program was based on a combination of mission-specific requirements, cost-effectiveness, and operational flexibility. This makes it a more suitable choice for aerial refueling than the C-17. In contrast, the C-17 was designed primarily as a cargo aircraft, which limits its ability to operate effectively as a tanker without significant modifications.

Commercial Designs vs. Custom Conversions

Boeing has already made engineering and design investments in the 767 for other countries, which further reduced the development time for the KC-46. Additionally, the C-5 massive transport is not particularly known for its nimbleness and maneuverability, while the C-130 Hercules is almost as nimble as a fighter aircraft and is used as a tanker but only in probe and drogue configuration. These factors contribute to the choice of the 767 for the KC-46 program.

Alternative Uses for Tanker Aircraft

The alternative of converting the C-17 to a tanker would require a substantial design rebuild, which is not an efficient use of resources. The 747or 767, which are already operating as tankers in other countries, provide a more cost-effective and time-efficient solution. Converting the 707 to a tanker was not the case; the 707 was developed from the KC-135 to become the KC-135.

For the U.S. Air Force, creating a KBC-47, KBC-767, or KBC-747 that can serve as both a tanker and a "bomb truck" for smart munitions could be a more practical approach. The KB-50, which was a tanker/bomber version of the B-50, provides a historical precedent for this dual-functionality. By retaining the tanker aspect, the aircraft can extend its range, albeit at the cost of bomb load.

Overall, the choice of the 767 for the KC-46 program was based on a combination of mission-specific requirements, cost-effectiveness, and operational flexibility. While a tanker/cargo hybrid like the KBC-767 or KBC-747 could offer additional benefits, the current configuration of the 767 remains the most practical and efficient design choice for aerial refueling missions.