by Master Sgt. Jeff Walston
307th Bomb Wing Public Affairs Office
Guy Bretches, an Air Reserve Technician and A-10 jet mechanic assigned to the 917th Maintenance Squadron, pulls clamps off a TF34 jet engine in the 917th Propulsion Shop at Barksdale Air Force Base, La., March 30, 2012. Bretches is conducting an inspection of engine parts to look for damage that might have occurred during an alternative fuel certification process. (U.S. Air Force photo by Master Sgt. Jeff Walston) Hi-res
4/10/2012 - Barksdale AFB, LA -- Both Reserve and Active Duty Airmen at Barksdale Air Force Base, La., jumped into the Air Force's Alternative Fuels Certification Program when they joined engineers from Wright-Patterson Air Force Base, Ohio, and Tinker Air Force Base, Okla., in an effort to evaluate an alternative jet fuel blend known as ATJ (alcohol-to-jet), at Barksdale AFB, March 26-30, 2012.
The office of the Secretary of the Air Force directed the effort to certify alternative fuels for operational use on all USAF aviation systems in an effort to reduce our dependence on foreign oil. The Alternative Fuels Certification Division (AFCD) at Wright-Patterson Air Force base, Ohio, was stood up in 2007 to manage this endeavor.
The AFCD is currently working three separate synthetic fuel certification efforts. The first, which has completed full certification, is known as JP-8/SPK, and is composed of 50 percent JP-8 and 50 percent synthetic paraffinic kerosene (SPK) produced using the Fischer-Tropsch process. The second alternative fuel blend is 50 percent JP-8 and 50 percent hydrotreated renewable jet (HRJ) fuel known as JP-8/HRJ. HRJ is derived from bio-feedstocks such as animal fats and plant oils (including Algal oils). AFCO has completed about 90 percent of the engine and aircraft testing for the HRJ certification program. An A-10 Thunderbolt II was the first aircraft to fly fully fueled on the JP-8/HRJ blend in March 2010 at Eglin Air Force Base, Fla.
The third alternative fuel blend is 50 percent JP-8 and 50 percent alcohol-to-jet (ATJ) fuel derived from cellulosic alcohols. The particular ATJ being evaluated is made from butanol, an alcohol feedstock, and then blended with traditional JP-8. In the future, the ATJ fuel could be produced from common, abundant cellulosic material like wood waste, grasses, or cornstalks.
There were numerous factors contributing to the decision by the TF34 program office, Oklahoma City - Air Logistics Center (OC-ALC), to have Barksdale host this test for the fuel blend. Foremost was the regular flow of testable TF34 engines that continuously move through the 917th Fighter Group's test facility.
"One reason Barksdale was chosen for this test was their vast availability of experienced professionals willing to do whatever it takes to help accomplish this essential research project," said Andrew Abdinor, TF34 Equipment Specialist, OC-ALC. "The TF34 maintainers at Barksdale are some of the best in the Air Force"
But, long before the fuel for the test found its way to Barksdale, many people were working to make the test here a success.
"Since late December of last year, AFCD has been evaluating the ATJ fuel properties, conducting materials compatibility and component rig testing in support of this TF34 test.," said David Dickey, propulsion lead for the Alternative Fuel Certification Division. "Quite a bit of engineering work is performed on each fuel candidate before we would ask anyone to put in into an actual engine."
A limited supply of ATJ fuel was manufactured by Gevo Inc., headquartered in Englewood, Colo., and shipped to Barksdale from Wright-Patterson AFB, Ohio, in 15 drums. That fuel had to be transferred to a storage tank where it was blended with JP-8. That responsibility fell to the Fuels Management Flight, 2nd Logistics Readiness Squadron, and Reserve personnel from the test cell at the 917th Fighter Group.
"A special apparatus was designed specifically for this operation. It's called a "Stinger" and was fabricated by the Water Fuel Maintenance shop here at Barksdale," said Senior Master Sgt. Dave Laun, the superintendent for the fuels management flight, 2nd LRS. "Patrick Barnes, a civilian, who works for the 2nd Civil Engineer Squadron designed the piece and put it together for the purpose of extracting fuel from the drums with the use of a double diaphragm pump, and putting the fuel into the storage tank where it could be blended with the JP-8."
The testing process at Barksdale was accomplished over a four day period, which consisted of running the TF34 Engine with JP-8 fuel at the test cell to set parameters as a baseline for comparisons after the ATJ test. The ATJ and JP-8 fuels were blended, and then the actual ATJ blend fuel run was conducted. After the test run was completed, the data was reviewed and the engine was removed from the test stand to be taken apart and checked by jet mechanics assigned to the 917th Propulsion Shop for any indications of abnormal wear although none was expected.
"We are especially interested in the high pressure turbine, (stage one and two), said Master Sgt. William George, test cell supervisor for the 917th Fighter Group.
"We pulled the hot section and will be looking for damage or wear to the parts, but the aft of the engine looks like it runs clean ... look at the end of that engine," he said.
Looks aside, examining the compiled data from the test will make the difference in whether or not the ATJ fuel gets a clean bill of health for the next phase of on-aircraft testing.
"If the engine's performance is comparable using these diverse fuels, the TF34 Engine Program Office will recommend to the Alternative Fuel Certification Division that the fuel can be utilized for flight testing," Abdinor said. "But, the ATJ needs to perform as well as the JP-8."
"The (engine) approval process is a very important step," Dickey said. "Without it, we can't fly."
All of these efforts support the Air Force's overall energy strategy which includes a goal to be prepared to cost-competitively acquire 50% of domestic aviation fuel from alternative fuel sources by 2016.
Barksdale Airmen can be proud with the role they performed in this alternative fuel evaluation process. Engine approval will clear the way for the next phase of the testing process - an A-10 flight demonstration using the ATJ fuel blend. This evaluation will be conducted at Elgin AFB, Fla., and is scheduled for late May 2012.