The 60th Air Mobility Wing, the last active-duty wing to fly the KC-10, has completed final inspections of its Extender fleet prior to the aircraft’s retirement in September.

Maintenance crews at Travis Air Force Base, California, on June 28 completed the K-10’s A-check, a routine biennial inspection that assesses wear, engines, landing gear, flight controls, avionics and other critical components. A base spokesman told Air & Space Forces Magazine that this is the final evaluation for the tankers, and no further inspections are planned.

“An A-check is a week-long inspection that is performed on a KC-10,” Master Sgt. Wessley Chandler, 60th MXS maintenance flight superintendent, said in a statement. “If the inspection is not completed, the aircraft is grounded until the inspection is completed.”

Maintenance personnel at Travis and other bases have long monitored the KC-10’s readiness with extensive A-checks, performing repairs and checking the system’s functionality to ensure operational readiness.

Now that the final inspection at the aircraft’s last operating base has been completed, Air Force soldiers are preparing to say goodbye to the KC-10 fleet for good. Once the Travis aircraft is retired in September, it will be moved to the Boneyard at Davis-Monthan Air Force Base in Arizona. There, the tankers will be stored and preserved outdoors, under the supervision of the 309th Aerospace Maintenance and Regeneration Group.

One of Travis’ KC-10s has been retired as a display aircraft at the National Museum of the United States Air Force in Ohio, rather than at the Boneyard. An Extender, serial number 84-0191, was delivered to the museum in April. That particular aircraft played a crucial role in 1986 during Operation El Dorado Canyon, serving as the primary tanker for Air Force F-111s targeting Libyan terrorists in Tripoli, the museum said.

The Extender, affectionately known as “Big Sexy,” has been in service for 42 years, flying a variety of combat and humanitarian missions. The aircraft flew its final combat mission from its last deployment assignment at Prince Sultan Air Base in Saudi Arabia in October. The last KC-10 left the East Coast in June 2023, leaving Travis as the only remaining Extender base.

“It’s sad to see the KC-10 go,” said Senior Airman Thomas Mihalyi, a team member in the 60th Aircraft Maintenance Squadron inspection department. “We’re entering a whole new era of aircraft. We’ve done four or five A-checks on the KC-46 and we’re all learning from them.”

As the base transitions from the KC-10 to the KC-46 Pegasus for aerial refueling, crews will complete their cruise training on the Pegasus before the Extender fleet is retired in two months.

Travis will receive its first KC-46A Pegasus in July 2023. The spokesperson added that the number of remaining KC-10s or incoming KC-46As at the base will not be disclosed, citing operational security. The new tanker promises greater survivability than the aging Extenders in contested environments, equipped with a host of self-protection, defense and communications capabilities. It can also carry more than 356,000 pounds of fuel, nearly twice what a KC-135 can carry, and nearly 170,000 pounds of cargo, nearly matching the capacity of a C-17. The Air Force expects to deliver a total of 179 Pegasus aircraft by 2028.