The US Access 5 project aims to prove that unmanned air vehicles are safe enough to be allowed into civilian airspace

UK newspapers report that a Northrop Grumman Global Hawk unmanned air vehicle illegally entered UK airspace while being demonstrated to the German military. Internet posters speculate that a Cessna 208B Caravan brought down on a night cargo flight over Alabama in October 2002 was hit by a UAV.

Both stories are vehemently denied by the US Department of Defense, but they illustrate the challenge facing advocates for civil use of unmanned air vehicles. The public - and other airspace users - remain to be convinced that UAVs are yet mature and safe enough to be allowed access to civil airspace. But unmanned air vehicles are increasingly ranging outside restricted military airspace as demand for a persistent airborne presence grows.

Lofty goal

Formal launch of a project to enableroutine flights by "remotely operated aircraft" - UAVs - in US civil airspace is imminent. After months of planning, the signing of a joint research agreement between NASA and the UNITE industry alliance was awaiting final legal clearance last week. With $101 million in NASA funding and an estimated $35 million from the industry, the Access 5 programme is focused on gaining routine airspace access for high-altitude, long-endurance (HALE) UAVs within five years.

The catalyst for commercialisation of UAVs is likely to be the US homeland security market. The task of patrolling America's borders and protecting its critical infrastructure is too immense to be accomplished without use of unmanned systems. But even paramilitary missions like border patrol require a level of routine access to civil airspace unavailable to UAVs today.

The US Department of Homeland Security is already moving to use UAVs. Under the Arizona border control initiative, two Elbit Systems Hermes 450 air vehicles are being used by US Immigration and Customs Enforcement to increase surveillance of the US-Mexico border to detect and deter terrorist activity and illegal cross-border trafficking of drugs and people.

A Congressionally mandated report on the potential uses of UAVs for homeland-security missions was due to be submitted by the beginning of this month, although no details have been released. Congress called for assessments of the potential for using UAVs to monitor remote areas along the northern and southern US borders; for monitoring critical infrastructure such as pipelines, power lines, power plants and water supplies; for monitoring the transport of hazardous materials; and for using land-based long-endurance UAVs to support the US Coast Guard.

The report was also required to look at the safety issues involved in the use of UAVs by agencies other than the US Department of Defense, and their operation over populated areas. Congress also asked for an evaluation of manufacturers' capabilities to produce air vehicles at higher rates if needed to meet homeland-security requirements.

While the momentum may be building fastest in the USA, other countries are paying increasing attention to the civil uses of UAVs. Australia's National Air Support (NAS) has signed a deal with General Atomics to offer the US manufacturer's Mariner UAV for civil maritime surveillance. Based on the turboprop-powered Predator B air vehicle, the Mariner has an increased endurance of 49h.

The Australian Customs Service plans to release by the end of April a draft tender for its Coastwatch civil maritime surveillance contract, the largest such programme in the world. NAS's subsidiary Surveillance Australia has held the Coastwatch contract since 1994, using Bombardier Dash 8s. Customs' original call for interest sought innovative approaches, including UAVs, but the agency stresses the solutions must be proven in the civil environment.

Australian company Aerosonde, meanwhile, believes it has more commercial UAV operating experience than any other company. Since 1995, the firm has logged 5,000h of commercial operations in 10 countries, says Maurice Gonella, manager of the new Aerosonde UAV operating base at NASA's Wallops Island, Virginia flight facility.

Under a three-year agreement with NASA, the Wallops Aerosonde facility will focus on Earth sciences but could provide a testbed for UAV operations in civil airspace and a toehold in the US homeland-security market. Flights began in February in the restricted airspace at Wallops, "but the concepts demonstrated could be applicable to future missions in less tightly controlled airspace", says NASA.

Cost concerns

Aerosonde has its own air operator's certificate in Australia, which has reduced the time for filing a flight plan "dramatically", says Gonella. The Civil Aviation Safety Agency (CASA) has certificated the company's mode of operations and not the vehicle itself, he says. "The Australian certification process is not vehicle-specific, it's organisation-specific. They understand the vehicle does not have the reliability of a manned aircraft, so it has to be operated in a way that mitigates the risk."

Proponents of civil UAVs are concerned that air-vehicle certification will drive up costs. The Aerosonde vehicle is designed to be low cost "so we can afford to send it into danger", says Gonella. "We expect a certain number not to come back." Despite its inherent expendability, the vehicle is programmed with safe recovery modes.

At its home base in Australia, Aerosonde has a 15km (8nm)-diameter cylinder of approved airspace up to 20,000ft (6,000m) in which to take off, flight test and land its UAVs. For missions outside that volume, the company's operator's certificate means that "CASA looks at the specific flight and takes the vehicle operation for granted", according to Gonella.

There are echoes of the Australian approach in US plans to secure equal access to civil airspace for unmanned air vehicles, particularly in the emphasis on establishing operating policies and procedures rather than regulating vehicle technologies. Unsurprisingly, the US plan is ambitious, with the ultimate goal of gaining airspace rights identical to piloted aircraft for UAVs providing safety performance equivalent to piloted aircraft.

The initial focus is on HALE UAVs as these are considered the most mature, and this is reflected in the make-up of the UNITE alliance, which includes US manufacturers Aero Vironment, Aurora Flight Sciences, Boeing, General Atomics Aeronautical Systems, Lockheed Martin and Northrop Grumman.

On the government side, Access 5 involves the DoD and US Federal Aviation Administration as well as NASA. The DHS is considering participating, given its interest in UAVs.

Access 5's high-end focus has drawn criticism from manufacturers of smaller, lower-altitude and shorter-endurance UAVs but participants argue that HALE vehicles have the least initial impact on civil airspace and allow a "build a little, test a little" approach to gradually integrating UAVs into the national airspace system (NAS). Approval for other classes of UAV may follow or proceed in parallel, depending on market demand, they admit.

Planners have laid out a four-step process to achieve routine airspace access for HALE UAVs. As envisaged, the four steps will take six years, not five, at a total cost of $360 million. NASA's reduced budget of $101 million is only sufficient to accomplish the first two steps, says programme manager Jeff Bauer, but the programme is structured to produce usable results at the end of each step and allow work on the second two steps to run in parallel with the first two if additional funding becomes available, potentially from the DHS. "They are keenly interested, and could contribute financially or in other ways," he says.

Step one will allow experimental certification of the air vehicle and routine operations above 40,000ft (12,000m), accessed by climbing and descending in restricted airspace. UAV operators will be able to "file to fly" above 40,000ft, a shorter process than the current FAA certificate of authorisation granted to Northrop Grumman for Global Hawk operations. "If the programme ended after Step 1, we would recommend to the FAA how experimental certification of a vehicle should be obtained," says Bauer.

Under Step 1 of Access 5, the UAV takes off and climbs in restricted airspace to 40,000ft - above most commercial traffic - where it enters Class A civil airspace. Air traffic control is able to command altitude, airspeed or route changes via the UAV control station, which communicates with the vehicle via line-of-sight or satellite link and which has conflict awareness with co-operative aircraft. For a normal landing or emergency recovery, the UAV descends through restricted airspace.

Step 2 allows routine operations above 18,000ft - alongside commercial traffic - again accessed through restricted airspace, and establishes the type certification basis for HALE UAVs. Additional capabilities include communications security enhancements and autonomous conflict avoidance with cooperating aircraft, recovery is again through restricted airspace.

Step 3 requires special airworthiness certification of the vehicle but allows routine operations above 18,000ft, accessed from a UAV-designated dual-use airport through Class C, D and E civil airspace. Additional capabilities include onboard weather detection, autonomous conflict avoidance with non-co-operating aircraft - otherwise known as detect, see and avoid - andvehicle auto-land at a dual-use airport via Class C, D and E airspace.

Step 4 - the end-state vision of Access 5 - reaches the goal of a standard airworthiness certificate for the air vehicle and adds the capability for emergency recovery via restricted airspace to a UAV-designated dual-use airport. "This assumes our recommendations are accepted and adopted by the regulatory authorities," says Bauer.

Behind the four steps are some 1,800 task items, including flight demonstrations, says Bauer. The first year is mainly the requirements development phase. Work will include an airports study to identify early sites for routine UAV operations. "We won't start at JFK [New York's Kennedy airport]," jokes Bauer. Flight demonstrations are unlikely to begin until the second year of the programme, although NASA may "piggyback" on other flight experiments to get an early look at human-system interface issues, he says.

Products of the Access 5 plan will include operating procedures for UAVs in civil airspace. "If a UAV is on final approach and has to do a go-around, how does it notify ATC? How do other aircraft react?" Bauer asks. Other recommendations will cover qualifications for human operators. "How many vehicles can an operator be responsible for?" he asks.

The Access 5 programme is aiming for a level of UAV safety that is equivalent to piloted aircraft. "We think that can be achieved by validating functional equivalency and not by dictating every part and serial number," says Bauer. "The concern from the industry side is about how to achieve increased levels of safety without making the cost prohibitive."


Source: Flight International