Air Force Tests ‘Drafting’ Flight To Save Fuel

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Key Takeaways:

  • Recent U.S. Air Force tests with C-17 aircraft demonstrated that flying in formation, with the trailing plane using specialized autopilot software at 3,000-6,000 feet behind the lead, could save up to $10 million annually in fuel costs.
  • Unlike previous "white-knuckle" fighter jet tests, this C-17 formation flying was found to be no more task-saturating for the aircrew than standard cruise flight, making it a practical fuel-saving method.
  • The tests confirmed successful in-flight rendezvous, day and night operations, and extended autopilot use, paving the way for further research to implement this practice across other aircraft and develop official Air Force procedures.
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Recent tests using two U.S. Air Force C-17 aircraft showed that flying in formation could potentially save the Air Force up to $10 million per year in fuel costs. The test flights, conducted in July, departed from Edwards AFB in California and flew to Hawaii and back. The trailing aircraft’s autopilot software was tweaked to enable it to maintain the optimum fuel-saving position, about 3,000 to 6,000 feet behind the lead aircraft. “Maintaining position in the [fuel-saving] formation is no more task-saturating for the aircrew than flying at cruise,” said Maj. Kyle Clinton, one of the pilots who flew the trailing C-17. The tests demonstrated in-flight rendezvous, day and night operations, and several hours of flight on autopilot, the Air Force officials said.

Donald Erbschloe, chief scientist for the U.S. Air Force Air Mobility Command, said the drafting concept has been tested before, but those tests involved fighter aircraft. Those airplanes had to fly closely at “fingertip” intervals for any benefit, requiring a lot of pilot effort for what Erbschloe described as “white-knuckle” flying. Erbschloe said in addition to confirming the fuel savings, assessing how the formation flying affected the aircrew was an important part of these latest tests. Research will continue next year with a two- to three-year project to test the fuel-saving practice with other aircraft and develop Air Force procedures for its implementation.

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