The C-5 is saving fuel under changes advised by a task force of reservists. (Jason Minto / Air Force)
Eighty-four percent of the Air Force’s annual $9 billion energy budget pays for jet fuel, and of that 60 percent is for 900 mobility flights per day moving cargo and people.
Even though the service has no control over fuel costs or the missions it is called to serve, it aims to “get better [energy efficiency] at every flight,” says Kevin Geiss, deputy assistant secretary of the Air Force for energy.
Geiss outlined some of the service’s energy-saving efforts in a Sept. 17 interview.
Here’s what you need to know:
Energy analysis task force
It’s the job of 19 reservists, who are private-sector pilots, civil engineers and other experts, to field-test industry best practices for adoption by the Air Force.
One example: EATF testing showed a more fuel-efficient descent used by commercial pilots — a “flight idle descent” — can save 500 pounds of fuel, or almost $280 at today’s prices, every time a C-17 lands. Savings are far higher for a C-5. While the approach cannot be used in all landings, particularly tactical landings, it has been conducted into the Manas Transit Center, Kyrgyzstan, throughout 2013 and is due to be approved for Al Udeid Air Base, Qatar, this year. The approach also has been approved for Charleston Air Force Base, S.C., and Travis Air Force Base, Calif., and is in the works for Joint Base Lewis-McChord, Wash.
“Previously, pilots at Manas were encouraged to delay their descents due to mountainous terrain; now they have a another reason to essentially glide to landing,” according to Geiss’ office.
More efficient KC-135 landings
When the aircraft got new engines in the 1980s, landing weight restrictions were unchanged. The planes continued to circle to burn off fuel to land carrying no more than 200,000 pounds. Recent EATF analysis showed the planes, with their better-performing engines, were capable of landing with up to 235,000 pounds. In August, instructions were changed to raise the landing weight restrictions, and that means millions of gallons of previously dumped fuel can be saved, Geiss said. The task force determined the change will save $1.2 million per year.
Air Mobility Command has ongoing studies to improve fuel efficiency. For example, the command is looking at how to optimize the center of gravity on aircraft. Optimization is important, Geiss said, because, as sensors and other new components are added to planes over time, the center of gravity changes, potentially increasing drag and reducing flying efficiency.
The Air Force set a goal in 2007 and reaffirmed it in 2010 to be prepared to fly on 50-50 blends of traditional and alternative fuels by 2016. With certification of the fleet on both synthetic and biofuel blends, the Air Force considers this goal complete.
Since 2006, the Air Force has reduced its total aviation fuel consumption by 12.4 percent — exceeding its previous goal to reduce consumption across the entire fleet by 10 percent by 2015 based on a 2006 baseline. Since 2006, mobility air forces have cut the cost to move one ton of cargo one mile by 24 percent, from $1.56 to $1.18. The current goal is to improve aviation energy efficiency — mobility, combat and training — by 10 percent by 2020, based on a 2011 baseline.■