The U.S. Air Force will save millions of dollars and airmen will be spared the dirty work of crawling inside fuel tanks, all by using a simple tool invented by a serving airman. The pressurized leak detection cup will cut the number of hours needed to detect for fuel tank leaks by up to 75 percent, saving the service more than a million dollars a year. To top it off, the new tool is 3D printed and costs just $15 to produce.

U.S. Air Force maintainers must keep a careful watch on the service’s KC-135 Stratotanker fleet. The aircraft date to the 1950s, making them even older than the vaunted B-52 bomber. The four-engine jet, a militarized version of the Boeing 707, entered service in 1956. Due to its age, the aircraft can develop mechanical problems.

The KC-135 can carry up to 200,000 pounds of jet fuel, ready to top off fighters and bombers on long-range missions. Stratotanker maintainers must check the aircraft’s voluminous fuel tanks, a process that until now involved airmen standing outside the tanks spraying them with water, with one airman inside the tank checking for signs of a leak. The whole process took on average 8 to 12 hours.

The engineers at Guhring UK have been able to rapidly prototype cutting tools in composite materials before printing them in metal.. Photo via Markforged.

Air Force Staff Sgt. Patrick Leach, with the 100th Maintenance Squadron, developed the pressurized leak detection cup to cut down on the amount of time it takes to detect leaks. As he explained to the U.S. Air Force:

“My innovation is a 3D printed cup which we can pressurize when pressed up against the surface of the aircraft,” Leach said. “This allows air to travel through any open channels on the surface and exit on the inside of the tank. We can then apply soapy water to the inside so we can see where the leak is coming through.”

The service certified the tool for use on the KC-135, and the Air Force says it will save at least $1.5 million in manpower costs at Leach’s airbase, RAF Mildenhall in the United Kingdom, alone. The tool will almost certainly save more money at other KC-135 bases as the Air Force rolls the tool out across units worldwide. Additionally, the tool is modifiable and can be made to fit other aircraft.

The Air Force has begun a service-wide effort to print parts for aircraft, particularly those long out of production. The service 3D prints toilet seat covers for C-5M Super Galaxy transports and handles for flight-specific coffee cups. Designing and 3D printing replacement parts save millions and time versus finding a vendor that can recreate parts no longer made by the original manufacturer.


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