The KC135R joining the collection of the National Museum of the United States Air Force, a/c 600329, accomplished an unprecedented refueling operation that saved lives. However, the distinction did not occur during the relative safety of developmental testing. This aircraft was flown in by the 154th Wing, Hawaii Air National Guard.

While conducting wartime refueling operations in the Gulf of Tonkin in May of 1967, the KC135 received an emergency refueling request from six Navy planes; two A3 Skywarriors, two F8 Crusaders, and two F4 Phantoms. The KC135 crew broke contact with the USAF’s F104s being fueled and went to meet the Navy planes. The emergency refueling operation had to be conducted at 5,000 feet because the Navy planes did not have enough fuel to climb to a higher altitude. While refueling one of the A3s, one of the F8s ran critically low on fuel. The KC135 crew guided the F8 to the A3’s refueling boom and daisy chained a refueling process from the KC135 to the A3 to the F8. The group then repeated the process with the other two planes.

The USAF recognized the significance of this operation by awarding the crew the 1967 Mackay Trophy for most meritorious flight of the year.

The KC135 is among the U.S. Air Force’s most iconic aircraft. First delivered to the USAF in June 1957, the KC135 has operated for over 60 years as the principal USAF refueling aircraft. The USAF recognized the need for a modernized jet tanker that could replace the slower propeller driven tankers of the postwar period.

The USAF purchased a total of 732 KC135s with the final aircraft being delivered in 1965. The aircraft extended the range of the bomber fleet in Strategic Air Command and enhanced the flexibility of Tactical Air Command’s fighters.

Throughout its lifecycle, the KC135 has received numerous upgrades that have extended its period of service. In the 1980s, roughly half of the 732 KC135s in the USAF’s inventory were reengined and redesignated as KC135Rs. The upgrade suite allowed the KC135 to offload 50 percent more fuel, become 25 percent more fuel efficient, and reduced operational costs. The KC135 continues to serve the USAF primarily in the National Guard and Reserves.