The Air Force and a Boeing [BA]-led industry team have demonstrated in-flight the ability of unmanned aircraft to rendezvous autonomously with tanker aircraft so that they could be refueled in flight, the Chicago-based company said recently.
The flight test occurred under phase one of the Air Force Research Laboratory (AFRL)-sponsored Automated Aerial Refueling (AAR) program. This initiative seeks to develop and demonstrate the technologies that will enable unmanned aircraft systems to approach and maneuver around tanker aircraft safely so they can receive fuel in flight via boom and receptacle operations.
The program is testing an AAR system, including a flight-control computer and control laws developed by Boeing Phantom Works, on a Calspan Learjet that is specially equipped to fly autonomously as an unmanned aircraft.
Boeing said during a recent flight test the AAR system autonomously guided the Learjet, the surrogate unmanned platform, up to a KC-135R tanker aircraft and successfully maneuvered it among seven air refueling positions behind the tanker: contact, pre-contact, left and right inboard observation, left and right outboard observation, and break away.
The AAR system controlled the Learjet for more than 1 hour and 40 minutes and held the aircraft in the critical contact position for 20 minutes, said Boeing.
“These tests show that we are making great advancements in system integrity, continuity and availability through improved relative navigation algorithms, control laws and hardware,” David Riley, Boeing’s AAR program manager within the Phantom Works, said in the company’s Dec. 4 statement. “They also show we are making great strides toward transitioning AAR technology into production.”
During a flight of the Learjet, a pilot in the cockpit takes the aircraft to and from the vicinity of the tanker and stands ready to assume the controls, if necessary. But he does not otherwise control the aircraft during the refueling maneuvering portion of the experiment, according to Boeing.
The AFRL has plans for a follow-on phase II that will include autonomous multi-ship operations and delivery of fuel to the surrogate unmanned aircraft, Boeing said.
“By adding an automated aerial refueling capability to [unmanned aerial vehicles], we can significantly increase their combat radius and mission times while reducing their forward staging needs and response times,” said Riley.