Air Force Making Headway on Fuel Efficiency Goals

The Air Force is stuck between a rock and a hard place. The service requires massive amounts of fuel to power its aircraft, but in a budget crunch, officials know they must curb consumption in order to save money and be less susceptible to a volatile oil market.

Taking lessons from the commercial sector, the Air Force is focusing on fuel-saving practices such as simulator-based training, removing excess weight from planes and implementing new flight techniques. The effort hit a major milestone earlier this year, when officials announced it had met its goal to reduce aviation fuel usage by 10 percent before 2015.

The largest single consumer of energy in the federal government, the Air Force in 2012 spent $9 billion on its power bill, 85 percent of which went toward aviation fuel. The service spends almost as much on fuel as it does on space activities like missile warning, communications satellites and space launch, said Acting Under Secretary of the Air Force Jamie M. Morin.

The Air Force set a baseline rate of fuel consumption in 2006, when it first established its 10 percent reduction goal. If the service still consumed fuel at that baseline rate, it would have paid $1.5 billion more in 2012, Morin said in a March briefing to reporters.

“A billion and a half [dollars] would have funded, for 2012, our full flying-hour program for all of our active duty bombers and attack aircraft,” he said. “This is real money that we did not have to expend on fuel. That’s especially important, given the volatility in the fuel market in recent years. Exposing ourselves to that much volatility is a risk for us.”

The Air Force has netted millions in savings over the last several years from better fuel efficiency, Air Force Gen. Paul Selva, commander of Air Mobility Command, told reporters in April.

Since meeting its 10 percent fuel reduction goal, the Air Force has kicked off a new program that focuses on overall efficiency rather than meeting a numerical target. The strategy centers on reducing demand, diversifying its energy sources and investing in new technologies that save fuel. 

“We know we may not be able to control exactly how much we fly, but we can control substantially how much fuel we use for each amount of flying we do,” Morin said.
The service used over 2 billion gallons of JP-8 jet fuel in fiscal year 2012 at $3.73 a gallon, according to mobility command officials.

“From 2001 to 2012, the price of jet fuel has gone up almost fourfold. So, we have looked at that as one of those things that we can’t control, but we can control how efficient we are with the fuel we can buy,” said Selva.

Setting a goal to cut back flights would be impractical for the combat fleet, which could be called to fly missions around the world at any time, Morin said. But the Air Force is looking to scale back gas usage by training its fighter pilots with fewer flights and more time on simulators.

“There is no substitute in training a fighter pilot for experiencing the live gravitational forces and the kick of an afterburner and all of those things, but there are parts of the training regime for those pilots and crew members that can and are better done in ground-based simulators,” he said. “So over the last couple of years, especially the Air Combat Command has done a very rigorous review of their training syllabus.”

For the mobility fleet — which is responsible for moving cargo and passengers, conducting medical evacuations and mid-air refueling — the Air Force is looking to the private sector for ideas on how to cut down on gas.

The service has worked on optimizing its routes and flight plans, benefiting from the experience of Air Force Reserve and Air National Guard pilots who have also worked for commercial airlines, Morin said.

“Shave a few knots of speed off your flight because your wind situation is different, and you’re reducing your fuel burn,” he said. “This is commonplace in the commercial industry, and we’ve been able to adopt it, in very inexpensive ways, into our fleet.”

Like the combat fleet, Air Mobility Command plans to introduce virtual training — such as a simulation for refueling airplanes — as a way of reducing the service’s reliance on JP-8.

“We’re on the verge of actually being able to very, very accurately simulate two airplanes refueling each other,” Selva said. “Simulators have great promise.”

Learning to refuel in mid-air requires a “huge expenditure of flying time” and is a skill that must be reinforced frequently. Practicing virtually would help drive efficiency, he said.

The refueling simulator would be high-fidelity training, and crews would feel as if they were flying, said Col. Bobby Fowler Jr., chief of Air Mobility Command’s fuel efficiency office.

“As we continue to fly missions, one of the things we are finding is the capability of simulators. Just like with the airlines, aircrews can get most of the actual training that is required via simulation,” Fowler said.

The simulator would reduce tanker-training hours by about 10 percent, Fowler said.

Even with sequestration, he expected the program would receive enough funding to continue and predicted the simulator would be operational by the end of 2017.

Besides saving fuel, Selva said the simulator is promising because it allows pilots to practice maneuvers that would be too risky to do in an actual flight.

The command is also reducing the weight of aircraft by removing non-mission essential cargo. For example, Fowler said that when not flying over water, life rafts are taken off planes.

“Why would we carry all that weight around?” Selva said. “For every pound of stuff you carry, you burn a tenth of a pound of fuel.”

The Air Force is also looking at optimization measures such as how best to load and balance cargo and how much fuel needs to be carried on each flight, Morin said.

Air Mobility Command is considering removing paper pamphlets, booklets and literature from a plane and storing the information on iPads to reduce weight. The initiative is still in its “break-in” stage, Fowler said, but he hopes it will be ready soon, though he did not give a specific start date.

On average, the initiative would remove 120 to 140 pounds of paper off a plane. The program would affect 1,214 mobility command aircraft, and overall would save $700,000 a year in fuel and $5 million in printing and distribution costs, Fowler said.

Sometimes new platforms and technologies naturally lead to greater fuel efficiency, such as when the Air Force upgraded its C-5 Galaxy cargo aircraft from A and B models to M models, which have a more powerful engine than the legacy planes.

That alone netted a 3 percent improvement in the burn rate of fuel per hour, said Kevin Geiss, deputy assistant secretary of the Air Force for energy.

Perhaps more important than the cost and energy savings, the upgrade increases the airplane’s range. For example, a pilot can now fly directly from Dover Air Force Base in Delaware to Incirlik Air Base in Turkey without having to stop in Germany, Geiss said.

 “So that provides you with one fewer landing and takeoff per trip over to Turkey and allows us to be more efficient, to haul more cargo for the amount of fuel that we’re burning,” he said. “It’s not having to make a choice between being efficient and being effective.”

Some regular maintenance tasks also help reduce fuel consumption, Selva said.

“On the KC-10 fleet, we’ve started a very innovative way of cleaning the engines that nets us about a percent and a half of fuel savings,” he said. “Doesn’t sound like much, but when you got 59 jets and they burn … 56,000 gallons of fuel when they cross the Atlantic, a percent’s not bad.”

The non-abrasive cleaning process uses a coal-based powder to clean the aluminum coating of the engines and blades to create better airflow.

Since the tankers are cleaned once every two years, Air Mobility Command averages the fuel savings to 1 percent per year, which saves $2 million in fuel annually, Fowler said.

The mobility command is also looking at a concept called vortex surfing to save fuel.

Vortex surfing resembles geese flying in formation. Two aircraft fly together, with one trailing behind the other by about 4,000 feet. The lead plane creates a vortex that reduces drag on the one following, yielding 8 to 10 percent fuel savings based on an initial test on C-17s at Edwards Air Force Base in California, Fowler said.

Because it is a highly technical maneuver, pilots will have to train to do vortex surfing. Planes will be flown on autopilot to decrease the risk of a potential crash given the close proximity of the aircraft to each other, said Fowler, who stressed that the technique is safe.

“I’m not sure I’m a fan of doing this as a normal tactic, but learning … [about vortex surfing] helps us learn some things about aerodynamics,” Selva said.

Defense contractors are also taking note of the Air Force’s need to reduce its fuel intake.

The Boeing Co. in April completed flight testing for the X-48C, a “blended-wing-body” aircraft that company officials said would be more fuel efficient than conventional aircraft.

The X-48C is an unmanned scale model of a heavy-lift plane, the body and wings of which are merged together to create a triangular, tailless aircraft.

“With a conventional airplane — tube and wing — you’ve got two big pieces, the fuselage and the wing, and they’re joined at 90 degrees to each other, and that winds up being heavier than” a blended-wing-body design, said Bob Liebeck, Boeing’s project manager for the aircraft. With the X-48C, “you don’t have to deal with that joint between the fuselage and the wing. It’s just a big continuous piece, and it comes out lighter.”

That lighter weight, along with a higher lift-to-drag ratio, drives fuel efficiency. Boeing estimates a blended-wing-body aircraft would net fuel savings of 60 percent when compared to legacy C-5 or C-17 cargo aircraft, and 18 percent savings compared to a new cargo aircraft that was built with the same technology and class of engine, Liebeck said.

The X-48C conducted 30 flights of around 30 minutes each and was controlled by a pilot stationed in a cockpit on the ground.

If the technology is further developed, Boeing officials believe blended-wing-body aircraft could be a good design for cargo transportation and refueling.

“It has a lot of … natural volume for fuel,” Liebeck said. “Because the center body is rigid, we can put two refueling booms on it instead of just one, like a KC-135 or a KC-10, and so we get twice as many gas pumps in the air.”

The plane flew up to 140 miles an hour and at a maximum altitude of 10,000 feet, which is lower and slower than cargo aircraft. However, Liebeck said these tests proved blended-wing-body aircraft can be safely flown like a conventional aircraft at low speeds.

Boeing is ready to build a manned flight demonstrator as a successor to the X-48C. But to fund such an expensive undertaking, the company would need a contribution from the Air Force or NASA in addition to its own internal research-and-development dollars, Liebeck said.

Topics: Aviation, Transport Aircraft, Defense Department, DOD Budget, Energy, Alternative Energy