KC-135: 50 years old and still refueling

US Air Force,

HICKAM AIR FORCE BASE, Hawaii: Airmen with the Hawaii Air National Guard's 154th Maintenance Squadron are servicing a fleet of aging KC-135 Stratotankers here.

“I'll read you the number, are you ready?” Tech. Sgt. Phillip Ferriman asked Senior Airman Thom Pialda, both electrical engineers with the 154th MXS. “L-24-6, no, wait. That's the ground.”

The Airmen were troubleshooting a problem. Something was preventing a light on the jet's wing from coming on when it was supposed to.

“We're trying to find a relay that may be heading out to the transformer,” said Sergeant Ferriman from behind his flashlight. He squinted, focusing hard on the web of electrical wires under a panel in the jet's flight deck.

This particular aircraft rolled off the line in 1960, and that is not old for a Stratotanker. Some will enter their 50th year of service this year, and the aging airframe does present some unique maintenance challenges.

“Some of these relays look like they came from the bottom of Pearl Harbor,” said Sergeant Ferriman.

But those who fly the Stratotanker say it's still a great aircraft.

“Yeah, it is an old airplane, but it's a lot of fun to fly,” said 1st Lt. Will Estes, a pilot with the Hawaii Air National Guard's 203rd Air Refueling Squadron. “They have new engines, a lot more power, and a lot of the avionics have been upgraded.”

The KC-135 airframe has received major improvements over the years to increase efficiency. For example, a recent avionics upgrade alleviated the need for a human navigator. An engine upgrade made the jet 25 percent more fuel-efficient, 25 percent cheaper to operate, 96 percent quieter and capable of off-loading 50 percent more fuel.

More upgrades are in the works, including improved communications, navigation and surveillance equipment.

After more squinting and searching, Sergeant Ferriman and Airman Pialda found the broken relay switch they were looking for. Shortly after that, their jet was ready to be back in the sky pumping fuel into another, probably younger, aircraft.