Achieving a legal framework to permit routine flights of unmanned aircraft in unsegregated airspace has been the goal of both industry and regulators worldwide for some years—but efforts to harmonize operating rules are moving slowly. Some nations are creating relatively permissive environments for commercial UAS, while others—most notably the U.S.—still effectively keep their airspace closed to civilian-operated remotely piloted aircraft.

Some nations allow UAS operations with hardly any questions asked; others “require an application very similar to something you might have for commercial airline operations,” Mark Sickling, of Scottish company Cyberhawk, told the Royal Aeronautical Society's UAS Operations conference here in September. Other countries do not permit any commercial UAS flights at all, he said.

Sickling, a former Royal Air Force Reaper pilot, is flight operations manager for Cyberhawk, which provides inspection services to the oil and gas industry. The company earlier this year claimed the world's first flight of an unmanned aircraft from an offshore drilling platform in the North Sea.

“We're really lucky in the U.K.,” he said. “We have an established framework, and it's pretty flexible on what it allows us to do. Once you start moving away from the U.K., things become far less clear. Different countries have different rules within Europe, and [in] the Middle East rules tend to be incredibly complex. As for the U.S., commercial operation of small UAVs at the moment is strictly forbidden.”

But U.S. airspace restrictions prevent CyberHawk using its U.K. experience to break into a “potentially massive market for industrial inspection, particularly with the number of refineries and production facilities,” Sickling said.

In the U.K., airspace integration has progressed along two parallel paths. For unmanned aircraft up to 20 kg (44 lb.), flown for commercial purposes under line-of-sight control or within 400 ft. of a building or public place, a permission-to-fly system has been created. To date, over 130 of these Aerial Work Permissions have been issued, covering operations ranging from a single flight in a single location on a single date, to multiple flights from various locations over up to a year.

Meanwhile, two blocks of airspace have been created where larger UAS can be flown. One is around the former RAF base at Parc Aberporth in Wales, now home to the National Aeronautical Center (NAC). The other links the military firing range at Salisbury Plain with Boscombe Down, the U.K. Defense Ministry's aerial test and evaluation facility.

Rather than being permanently closed to non-UAS air traffic, these two blocks are activated by “notices to airmen,” or Notams, when UAS activity is planned. Even during periods of activation, a crossing service for manned aircraft can be provided by local air traffic controllers.

The Civil Aviation Authority (CAA) began drafting guidance for flying UAS in U.K. airspace around the year 2000, and published its first guidelines in June 2001. In May 2002, these were augmented and republished as Civil Aviation Publication (CAP) 722, the fifth edition of which was released in August.

CAP 722 is widely seen by other regulators as a benchmark. “From my perspective, especially when I was a regulator, CAP 722 was probably the most valuable document that we had out there,” said Doug Davis, former manager of the FAA's unmanned aircraft program office, at the Autonomous Systems Technology Related Airborne Evaluation and Assessment conference here last month. “It was so mature, so well thought-out and well structured. It really was a global exemplary document.”

“I think the regulations are proportionate,” says Gerry Corbett, editor of CAP 722. “They're light-touch where they need to be, but they apply where they need to. It seems to be working fairly well at the moment.”

The CAA aims to process Aerial Work Permission applications within 28 days. Documentation and other requirements vary case-by-case, but applicants must show they propose to use an airworthy aircraft operated by accredited personnel. “They provide us with a sort of mini operations manual, and as long as the aircraft and the pilots are certified, and they operate in accordance with any stipulations we put in the permission, then that's fine. It's relatively simple,” he says.

The process by which the two Notam-activated airspace blocks were created is significantly lengthier. Corbett likens it to the planning procedure required to gain permission to construct a road or extend a building. The sponsor/applicant must conduct extensive consultation with all stakeholders—including those on the ground beneath any proposed flight path. Legitimate objections that could be made include environmental issues, such as pollution or noise.

Once submitted, a completed application will take at least six months to fully process, but the consultation —which has to be completed before the application is submitted—could take much longer. The Parc Aberporth airspace change took more than five years to enact.

CAP 722 stresses the need for unmanned systems to demonstrate equivalence to manned aircraft in safety, airworthiness and other key areas. It does not involve the regulator in a discussion about the nature of the work done by the aircraft. In the U.S., where the FAA has been mandated to establish six similar blocks of airspace as test sites for larger civil UAS, the regulator has become mired in public concerns over privacy.

In a Nov. 1 letter to Congress, acting FAA administrator Michael Huerta said the agency would fail to meet its deadline of the end of 2012 to identify the six sites. He cited the need to “appropriately address privacy concerns regarding the expanded use of UAS” as the primary reason for the delay.

“The headline's always been very simple: they've got to be safe to fly, and they've got to be flown safely,” says Corbett. “Obviously, there's a raft of complex stuff underneath that, but if the aircraft will stay in the air and can be operated appropriately, then [the CAA] does not really have any reason to stop it flying. We're not allowed to stop people going about their work: we can only stop things from happening on safety grounds,” he says. “It's for other people—other elements of the government—to stop things for other reasons.”

Does this mean the U.K. has a competitive advantage? “Possibly,” Corbett says. “With small [UAS] you want to fly them where the use is. If it's test and evaluation, then yes, maybe—that's one of the reasons the additional airspace was created around [the NAC]. But the big thing is it's not a race, and the U.K. isn't going to forge ahead of anybody. Whatever you stick in the air affects international air traffic, so it's all got to be done as harmonized international work.”

Such work is ongoing—a plethora of different groups convened under different auspices, often involving the same subject-matter experts, meet regularly and are making progress. But there are a number of differences between nations that make harmonization tricky. Corbett points out that, in general, U.K. law often works on the basis that if something is not prohibited then it can be done, whereas the tendency in other parts of Europe may be to only consider an activity to be legal if it is specifically permitted.

In the U.S., Customs and Border Patrol unmanned aircraft are considered as state-operated aircraft, and are treated similarly to military UAS, while in the U.K. police and fire services that have used UAS have been dealt with under civilian airspace regulations.

The missing ingredient for all airspace integration efforts is operational data. Experience gained by western militaries operating UAS in combat zones is not seen as likely to help make the case for safe civilian operations, even when—as at Kandahar—remotely piloted aircraft are largely treated as equivalent to civilian and military manned aircraft. Corbett is optimistic this is one area where the U.K.'s regulatory work may provide some answers.

“Hopefully [the segregated airspace blocks for larger UAS] will produce a body of evidence which can be used elsewhere,” he says. “I want to see stuff up there, building time, proving to the world that they don't fall out of the sky, and having manned aircraft interact with them in a controlled manner.”

*NASA and the Pentagon operate at other altitudes as well.
Current UAS Applications and Altitudes of Operation in the U.S.
UAS Type UAS Use Altitudes of Operation (ft.)
Large NASA research projects* >60,000
Pentagon military training* 18,000—60,000
Homeland Security Department
border surveillance 400—18,000
Small Search and rescue 400
Wildfire tracking 400
Crime scene surveillance 400
Source: Government Accountability Office