The U.S. Air Force’s KC-46A Pegasus Update
KC-46A Pegasus on approach to a Joint Base McGuire runway. Photo by Mike Colaner.
Boeing’s KC-46A Pegasus program has been fraught with delays caused by several bid cancellations, system redesigns, and recent quality control issues. Originally, a plan to bid for a replacement for the oldest of Boeing’s KC-135s in the U.S. Air Force’s inventory was first proposed shortly after the new Millennium, totaling one hundred aircraft. After some delays, the current bid envisioned the first KC-46A being delivered in the mid-2017 time frame, but the first tanker was ultimately delivered in January of 2019, about a year and a half later than planned. The most recent bid calls for Boeing providing 179 total tankers in multiple lots; so far four small lots of the new jet have been ordered, totaling fifty-two aircraft as of June, 2019. Importantly though, the new tankers are being delivered and have been used in limited operational use.
KC-135R with a pair of F-15E Strike Eagles. Photo by Shawn Byers.
The first U.S. Air Force next generation aerial tanker program was launched in 2001, to replace one hundred already-aging KC-135s built during the late 1950s and early 1960s. Known as the KC-767, the aircraft was chosen over an Airbus competitor that was based upon the popular A-330 airliner. Multiple amendments to the original contract were made, and a government investigation led to halting the negotiations for the final number of, and ownership of the aircraft (some or all of the new tankers were to be leased instead of purchased). By early 2006, five years after the initial program was started, it was cancelled, and a new program for the tanker aircraft was begun again.
In January 2007, the Air Force issued the KC-X Aerial Refueling Aircraft Request for Proposal. The program called for one hundred seventy five aircraft and four developmental aircraft. Boeing’s entry was based upon a freighter version of their B-767-200 airliner, with the wings of their -300 (stretched) airliner, and their latest B767-400 avionics. A larger engine model (when compared to the airliners) and a fly-by-wire refueling boom were included in the bid too. The air refueling operator now sat in the cockpit versus the tail in the KC-135/KC-97 layout, remotely operating the refueling boom via a television monitor. Boeing’s main competition again was Airbus, teamed with Northrop Grumman. Their KC-30 entry won that competition in early 2008, and their variant was designated as the KC-45A. Boeing protested flaws in the bidding process, which the General Accounting Office upheld. In September 2008, this bid was canceled too.
After a long review and rewriting of the program’s requirements, another request for bids was requested in September, 2009. Both Boeing and Airbus/Northrop Grumman bid designs. In February 2011, almost a decade after the first tanker bid was announced, Boeing’s KC-767 was once again named the winner. Newer improvements in this design included an updated cockpit with some 787 airliner avionics and a modified KC-10 Extender refueling boom. The new winning design became the KC-46A Pegasus.
Boeing B-767-2C/KC-46A developmental airframe refueling an F-15E. USAF photo by John D. Parker.
The four developmental airframes, known as the B-767-2C version, began flight tests during 2014, and production KC-46s were planned to be delivered from 2015 through 2027. Capable of offloading and taking on fuel by air refueling, the aircraft is equipped with both a refueling boom underneath the tail, a permanent hose and reel refueling system on the centerline belly, and mounting capabilities for an additional two hose and reel pods on the outboard parts of its wings. The aircraft would be dual-certified, by both the FAA and the Air Force.
By mid-2015, an issue was identified with the aircraft’s fuel systems that led to some design changes before certifications would be given. One aircraft’s fuel system was compromised when a chemical not part of the planned test was introduced into the system, and the aircraft’s hardware had to be tested to see if any components were damaged.
KC-46A on the ground at Seymour Johnson AFB’s 2019 air show. Photo by Shawn Byers.
Issues with the duel-certification of some wiring harnesses caused further delays. Additional time was needed to work on the main air refueling boom software too. New delivery dates now called for the first eighteen KC-46As being delivered by April 2016. Then, that first delivery then slipped until April 2017, partly due to lengthened flight testing and delayed parts production.
The delivery date of the first eighteen aircraft soon slipped again, into 2019. On January 10, 2019, the U.S. Air Force formally accepted their first KC-46A. Two short delays in accepting more aircraft occurred after this first formal delivery, as post-delivery inspections found Foreign Objects (FOD – tools, fasteners and trash) within the aircraft. These issues were rectified within weeks, but still the delivery dates of many first lot aircraft were pushed forward yet again.
First KC-46A Pegasus arrives on its delivery flight to McConnell AFB. USAF photo by A1C Alan Ricker.
Basing of the first KC-46A refueling squadrons was divided up among four Commands; the active Air Force’s Air Mobility Command chose to equip the 22nd Air Refueling Wing at McConnell AFB as their first unit to operate the Pegasus. The 97th Air Mobility Wing at Altus AFB (of the Air Education and Training Command) has received multiple KC-46As as the main training unit for all KC-46A operators; their first airframe arrived on February 3, 2019. The first non-training Wing to receive their aircraft occurred on April 23, 2019, as the 22nd ARW saw their first Pegasus land on its runway. The New Hampshire Air National Guard’s 157th ARW is expecting their first KC-46A sometime during the autumn of 2019 and the Air Force Reserve’s 916th ARW expects their first aircraft a year later, in 2020.
The Air Force describes the mission of the Pegasus as: “The KC-46A is the first phase in recapitalizing the U.S. Air Force’s aging tanker fleet. With greater refueling, cargo and aeromedical evacuation capabilities compared to the KC-135, the KC-46A will provide next generation aerial refueling support to Air Force, Navy, Marine Corps and partner-nation receivers.”
Additionally, the KC-46A will be able to continue to do other important missions, like the KC-135Rs: “The KC-46A can accommodate a mixed load of passengers, aeromedical evacuation and cargo capabilities. Two high-bypass turbofans power the KC-46A to takeoff at gross weights up to 415,000 pounds. Depending on fuel storage configuration, the aircraft can carry a palletized load of up to 65,000 pounds of cargo. The KC-46A can carry up to 18 463L cargo pallets. Seat tracks and the onboard cargo handling system make it possible to simultaneously carry palletized cargo and passenger seats in a variety of combinations. The KC-46A is also equipped with a number of self-protection, defensive and communication features making it more survivable in a contested environment.”
On May 7th, 2019, a McConnell AFB-based tanker refueled a quintet of USAF F-16s and their KC-10 support aircraft while enroute to a training exercise in Alaska. So after a prolonged gestation period, and the need to overcome some aerodynamic, design and quality issues, the KC-46A is now in limited operational use, and the Air Force will slowly gain more airframes with these additional lots… After a very slow start, the next generation of air refuellers is starting to make its mark in the sky with the U.S. Air Force.