AFRL Completes Automated Aerial Refueling Positions and Pathways Flight Tests

  • Published
  • By Air Vehicles Directorate
  • AFRL/RB
WRIGHT-PATTERSON AIR FORCE BASE, Ohio --  Researchers from AFRL and Boeing Phantom Works completed automated aerial refueling (AAR) positions and pathways flight tests. During the series of flights, the research team demonstrated the AAR system's capability to autonomously execute all aerial refueling maneuvers while flying in close formation with a tanker, as well as its capacity to perform practice breakaways. A Calspan Learjet acted as a surrogate unmanned refueling receiver aircraft, using the AAR system to successfully track the tanker's flight path--via a Boeing-provided flight control computer (FCC) with Northrop Grumman Precision Global Positioning System--in order to position itself in a trail formation; fly up to the tanker; and make the necessary adjustments to achieve observation, precontact, and contact refueling positions.

The purpose of the AAR program is to develop the capability to use the existing Air Force tanker fleet for boom and receptacle refueling of unmanned air vehicle systems and to demonstrate this capability using operationally representative subsystems. Researchers were able to validate many AAR technology advancements during these flight tests, wherein a Learjet was manually flown to the transition point behind a Boeing KC-135R (provided by the 107th Air Refueling Wing of the New York Air National Guard). A Boeing flight test engineer (FTE) aboard the Learjet engaged the Boeing-provided FCC and control laws, which subsequently employed relative navigation state data derived from a precision Global Positioning System solution to autonomously fly the Learjet to the observation position on the tanker wing. The Boeing FTE then used a control station on the Learjet to fly to the precontact and contact positions after receiving approval from the tanker crew. During the flights, the AAR system remained engaged for over 1 hour and 40 minutes and held formation at the contact position for 20 consecutive minutes.

During another test flight, the Learjet followed the Boeing KC-135 through two complete refueling orbits. Throughout the positions and pathways flight test, the Learjet was engaged for over 8 hours near the tanker. In addition to demonstrating the proper flight characteristics for a refueling receiver, the AAR research team continues to make strides towards preparing AAR technology for transition to production systems. By leveraging improved relative navigation algorithms, control laws, and hardware, the team has achieved advances in system integrity, continuity, and availability.