According to this Aviation Week article from October 2012, the US Air Force Research Laboratory ran a program called Surfing Aircraft Vortices for Energy ($AVE) to test/prove that autopilot settings could be adjusted to allow C-17s to fly in formation using the wingtip vortices of the lead plane to reduce fuel consumption of the following planes. They seem to have found upwards of a 10% reduction in fuel for the following planes.

The article indicated that previous experiments involved hand-flying of the aircraft in formation which required the equivalent concentration, focus and exhaustion levels of aerial refueling and was unfeasible for long duration flights, therefore the tests proposed to incorporate the formation flying into the autopilot

Does anyone know if these auto-pilot configurations have been put into use in line C-17s or other USAF transport aircraft?

  • $\begingroup$ So far I found no evidence that line C-17 receives this modification to the autopilot system. However the test aircraft had this modification and it proved satisfactory. $\endgroup$
    – vasin1987
    Commented Jul 15, 2015 at 2:11

1 Answer 1


The C-17 has a special autopilot system including a component called the MILCAS-FR formation flying system by Honeywell and here is a link a sales brochure.

My military flight time was not in a C-17 but in my opinion once the precise formation locations were determined that achieve the fuel savings in the article it would be a simple decision to use them on any given formation flight based on the tactical situation. The requirements of each mission would drive that decision.

  • 1
    $\begingroup$ So it sounds like this close "vortex surfing" routine has been built into the autopilot software, and its use is determined on a mission-by-mission basis. Excellent, welcome to Aviation.SE, and thanks for serving! Your screen name indicates you may have flown something a bit faster and more nimble than a transport? $\endgroup$
    – FreeMan
    Commented Apr 18, 2016 at 12:05

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