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Air Force tests new constant pressure fuel structure

  • Published
  • By John Ingle
  • 82nd Training Wing Public Affairs
SHEPPARD AIR FORCE BASE, Texas --  The Air Force officially began its tests of a 50-50 mixture of synthetic and JP-8 fuels in a Type 3 constant pressure fuel hydrant system May 18 at Sheppard's 364th Training Squadron.

Fuel tankers arrived at Sheppard May 17 to unload 113,000 gallons of fuel, including five trucks with 100 percent synthetic fuel and three with the 50-50 blend. 

The Type 3 system is a constant pressure fuel structure that, as the name suggests, provides a constant fuel pressure through the pumps, lines, truck, aircraft and back to the pumps. This is particularly advantageous at operational locations where time is a factor. With this system, multiple aircraft can be refueled without a reduction in performance of the pumps.

In older systems, the pressure would degrade if multiple aircraft were being refueled.

The purpose of the test is to determine the long-term effects of the blended fuel in a system. During testing, the hydrant system will be regularly monitored to determine whether or not any detrimental effects or other abnormalities occur over the extended period of time. Tech. Sgt. Randy Davidson, Air Force Petroleum Agency (AFPET) Logistics Education Advancement Program noncommissioned officer, said he will conduct monthly tests between now and the end of the survey.

Sergeant Davidson said they have specific parameters for the fuel and that there have been no indications in previous tests that they will experience any issues during this test.

"This is a long-term durability test to see if the system can handle the 50-50 blend," he said. "We hope we get the same consistent levels."

Ray Bunch, AFPET quality assurance inspector, said Sheppard was a natural fit to test the hydrants because it doesn't interrupt the day-to-day flow of an operational base.

"The reason we picked Sheppard is this is a training system," he said. "We can keep the fuel isolated."

The tests will last until about October or November. Master Sgt. Jefferson Guillory III, the squadron's superintendent, said the six-month test period is too long to shut down a fuel yard.

"No one wants to give up their Type 3 system on the active side," he said. "Here we have a closed system that's specific for training. It doesn't leave here."

The process to begin this round of tests began May 13, Mr. Bunch said, when the entire system was "de-fueled" of JP-8 and cleaned in preparation for acceptance of the 50-50 blend. Sergeant Davidson said he conducted tests to make sure the system was ready to receive the new fuel product.

"Once we got our baseline and saw the levels were good, then we started off-loading from trucks," he said.

Once the fuel was in the tanks, the blending process began by "spinning" the tank, or running 1,200 gallons per minute through the system.

Mr. Bunch said the Air Force began 50-50 blend tests in 2006 at Tinker Air Force Base, Okla. So far, the Air Force has certified the B-52 Stratofortress, C-17 Globemaster III, B-1 Lancer and F-15 Eagle for non-combat operations. The F-15 should receive full certification soon, while the KC-135 Stratotanker and KC-10 Extender, the service's air refueling aircraft, are pending certification.

The Air Force hopes to be ready to deploy the 50-50 blend to all airframes within the next couple years, making these tests critical for the certification of Type 3 hydrants.

"Once we reach 2011 and we say the aircraft are ready to go and we're going to put it in the systems, we want to make sure there aren't any issues," Mr. Bunch said.