The U.S. Navy has not determined how to fit a “due regard” radar on its unmanned MQ-4C Triton, which will likely start initial operations in 2017 without the subsystem intended to help protect it from midair collisions. But the Triton will enter service with more capability than any other unmanned aircraft to “detect and avoid” other aircraft, the Navy’s program manager asserts.

During a panel discussion at the Unmanned Systems 2014 conference on May 14, Capt. James Hoke, the Navy’s Triton program manager, said the Global Hawk “persistent surveillance” maritime derivative will come equipped with a traffic alert and collision avoidance system (Tcas) and automatic dependent surveillance-broadcast (ADS-B), both transponder-based “cooperative” systems that require other aircraft to have transponders. Due-regard radar will make the Triton capable of “non-cooperative” detection of aircraft that are either not equipped with a transponder or not using it to avoid being detected. The name coined for the radar refers to an International Civil Aviation Organization (ICAO) requirement that military and state-owned aircraft be flown with “due regard for the safety of navigation of civil aircraft.”

“When I first came on the program, my first thought was how hard can this be—we have air-to-air radars all over the place,” Hoke related. “It’s the space, it’s the power, it’s the cooling. You don’t get a lot of airflow up at 50,000-60,000 feet. So you’ve got all these technical issues that we have not cracked the nut on yet.”

More than a year ago, the Navy instructed Triton prime contractor Northrop Grumman to stop work on the due-regard radar subsystem then under development by subcontractor Exelis because of technical challenges and cost growth. “We do not yet have a clear roadmap to get back on track with that effort,” Hoke said. “But I don’t think I’ve done a good enough job of advertising this: we’re going to be introducing Triton with capabilities that are not on any other unmanned system right now. We have Tcas and we have ADS-B, so we will know everybody who’s out there squawking…Obviously, there are some people who don’t squawk because they’re flying their Cessna up and down the coastline or you’re in another part of the world and they don’t want to be seen and that’s obviously a concern.”

Hoke said the program is currently “doing a lot of study, a lot of safety case analysis” on parts of the world where it expects the Triton to fly, in an effort to assess the air traffic and measure the flying risk. He said it is possible but not likely that the Navy will have a due-regard radar solution by the time the Triton reaches early operational capability with two delivered air vehicles in 2017, probably based in Guam. The service plans to declare formal initial operational capability once four Tritons are delivered.

In March, the Naval Air Systems Command announced that the first MQ-4C test aircraft had completed envelope expansion flight-testing at Northrop Grumman’s facility in Palmdale, Calif. The service plans to ferry the aircraft across the country to Naval Air Station Patuxent River in Maryland, this summer for further testing. It has already obtained a certificate of authorization from the Federal Aviation Administration to make the flight, Hoke said.