Air Transport

US military officials want to prove to the US Federal Aviation Administration that ground-based phased-array radars and air safety statistics can help ease the process of integrating unmanned air vehicles into civil airspace.

The FAA bars unmanned aviation's access to civil airspace until the industry can prove an equivalent level of safety with manned flight. A precise definition for the meaning of that term, as well as the technology to comply with it, remains far out of reach of today's operators.

But US Army officials attending the Association of Unmanned Vehicle Systems International's 22-24 April Pathfinder symposium in Huntsville, Alabama, said they will try to partly satisfy the FAA's concerns at two key locations: El Mirage and Beale AFB, California.

El Mirage is the home of General Atomics Aeronautical Systems' flight-test facility, while Beale is the base for the US Air Force's Northrop Grumman RQ-4 Global Hawks. Unmanned flights at both locations are now cleared through a laborious process known as obtaining a "certificate of approval".

© Northrop Grumman

At both sites, ground-based phased-arrays will be used to spot manned aircraft lacking working transponders, allowing ground operators to steer unmanned aircraft out of the way. A mid-air collision with a manned aircraft lacking a transponder, such as an ultralight, is one of the FAA's principal concerns.

At the same time, the military is collecting air safety data at both locations to establish a baseline for manned flight. The same data for the unmanned types based at both sites will be inserted into the database. The goal is to show the precise change in the level of safety, allowing the military to show how mitigating steps - such as the ground-based radars - can close the gap.

The military's goal is not to win universal acceptance for unmanned aircraft in civil airspace, but merely greater freedom to operate in the airspace at the two locations.

Military officials acknowledge the same technique would not be adequate at any but the most remote locations. A final decision by the FAA on granting the military's proposal for Beale and El Mirage could come later this year.