Stratotanker certified to use synthetic fuel blend

  • Published
  • By Mark D. Diamond
  • Air Mobility Command Public Affairs
SCOTT AIR FORCE BASE, Ill. --  The final weeks of August were important for the U.S. Air Force synthetic fuel program, according to officials with Air Mobility Command Test and Evaluation directorate.

On Aug. 21, at March Air Reserve Base, Calif., the Air Force began conducting ground and flight tests with the KC-135 Stratotanker using an alternative fuel mix. The tests concluded with a KC-135 demonstration that included the first-ever aerial refueling using the Fischer-Tropsch synthetic fuel blend.

The tests are part of an on-going effort to certify all Air Force aircraft by 2010 to use the fuel blend, that mixes JP-8 fuel with fuel produced using the Fischer-Tropsch process -- a process used to convert carbon-based materials into synthetic fuel.

According to Stephen Chicosky, AMC Test and Evaluation test manager, the KC-135 operational assessment was accomplished to assess the suitability of alternative fuel with that airframe.

During the KC-135 assessment, Master Sgts. Don Lenhart, Fred Carver and Alecia Judd from the AMC Test and Evaluation Squadron at McGuire AFB, N.J. collected data.

Mr. Chicosky explained that to isolate the data, the assessment was completed in several stages.

During the first stage of the KC-135 assessment, he said the team established a baseline by collecting data on all four engines operating with JP-8 fuel only. After collecting the initial data, the team removed the JP-8 from the No. 2 fuel tank and then filled it with the synthetic fuel blend.

"The team ran the No. 2 engine on the ground and it operated fine," added Mr. Chicosky. "There was no noticeable difference between the JP-8 fuel and the synthetic (blended) fuel."

Following the ground testing, the KC-135 made its maiden flight using the synthetic fuel in the No. 2 engine only. The remaining three engines operated with JP-8 fuel. The flight was accomplished by an aircrew from the 336th Air Refueling Squadron at March ARB.

"The initial flight lasted about 50 minutes and the crew said they didn't notice any irregularities in the No. 2 engine; they said the flight was 'unremarkable,' which is what we were looking for," said Mr. Chicosky.

On Aug. 28, the team completed the third and final stage of the certification, flying the aircraft with all four engines operating on synthetic fuel only. Mr. Chicosky said the KC-135 departed March ARB with 60,000 pounds of synthetic fuel. During the flight, which lasted just over two hours, the aircraft burned approximately 24,000 pounds of synthetic fuel. The flight also included the first-ever aerial refueling using the synthetic fuel blend. During the in-flight refueling, the KC-135 crew transferred 17,000 pounds of synthetic fuel to an F-22 Raptor assigned to the 411th Flight Test Squadron at Edwards AFB, Calif.

"The entire [KC-135] flight was uneventful, in that the aircraft operated just as it would using JP-8 fuel," explained Mr. Chicosky, who was on board the aircraft during the final flight. "It was a successful flight."

In fact, he said, the entire certification process was a success.

"Everyone involved did an outstanding job," added Mr. Chicosky. "Everyone worked together to ensure the KC-135 certification was a success."

In addition to March ARB personnel, he said AMC also partnered with KC-135 engineers from Tinker AFB, Okla., and personnel assigned to the 77th Aeronautical System Wing and Air Force Alternative Fuels Certification Office at Wright-Patterson AFB.

Certification on the remaining AMC aircraft - including the C-5 Galaxy, KC-10 Extender and C-130 Hercules - will be completed by the end of this calendar year, according to AMC's Chief Scientist, Dr. Donald R. Erbschloe.

Dr. Erbschloe said what the Air Force is doing to certify its fleet to use the Fischer-Tropsch synthetic blend is only one part of a host of actions that need to occur before alternative fuel becomes a reality. He said one of the key issues concerning the alternative fuel effort is "supply and demand."

"A critic may argue that it is all well and good to certify our Air Force aircraft, but if the alternative fuels are either not available or too costly, what good is it?" Dr. Erbschloe explained. "Well, one major achievement - which was accomplished during the C-17 certification process (October 2007) -- was to develop a thorough, structured set of procedures to validate and test the efficacy of any alternative fuel -- not just Fischer-Tropsch -- in our Air Force systems. All of this leads to improved energy security for our Air Force."

He said those procedures -- the Military Specification Handbook for Alternative Fuels -- is the process the Air Force will use when it tests biofuels and other future potential energy sources. However, Dr. Erbschloe added that the Air Force can't and shouldn't do this by itself.

"The answer is that a number of players - the U.S. fuel industry, government, other major fuel consumers -- all need to work together to produce both the supply and demand to make this a viable and affordable alternative," Dr. Erbschloe said.

The command's chief scientist said synthetic fuel may be expensive now, but it could cost significantly less than that produced from oil at its current price if it is mass-produced.

He also said the Air Force will continue to learn and improve its alternative fuel methods and tools as the Air Force fleet certification is completed. "And we'll be better prepared, more capable and, hopefully, quicker when we consider other alternative fuels to use in the future," added Dr. Erbschloe.