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Voss, P.B., Rethinking the Regulatory Framework for Small Unmanned Aircraft, Proceedings of the 2013 International Conference on Unmanned Aircraft Systems, Atlanta, Georgia, May 28-31, 2013. (ICUAS-13-161 with corrections and additions)

Abstract— Small Unmanned Aircraft Systems (sUAS) have the ability operate in chaotic and heterogeneous environments near the ground that are inaccessible to manned aircraft. This is significant because navigable airspace, which is in the public domain and preempted by federal laws, is defined by the minimum safe altitudes of flight. Since many sUAS arguably have no minimum safe altitude, they could potentially expand navigable airspace to the ground, posing a serious challenge to property rights, privacy expectations, and local control. This paper discusses the issue in historical context, raises new questions about the current direction for sUAS regulation, and suggests an alternative framework that would have benefits for governmental efficiency, the civilian UAS industry, and the public at large.

Keywords— airspace management, navigable airspace, unmanned aircraft, UAS

I. INTRODUCTION

Unmanned aircraft technology has advanced rapidly over the past two decades; a field that was only recently the domain of hobbyists and aeronautical engineers has grown into a multi-billion-dollar industry [1]. Small Unmanned Aircraft Systems (sUAS), which are generally defined by aircraft weighing less than 55 pounds [2], represent a particularly promising area for growth. Some of the most advanced sUAS are now smaller than Frisbees, yet can transmit high-definition video, detect chemical plumes, or even navigate autonomously. These sUAS are poised to transform fields ranging from aerial photography and agriculture, to ecosystem studies, meteorology, and public safety [3].

Paradoxically, as sUAS have become smaller and more reliable, the Federal Aviation Administration (FAA) has become increasingly concerned about the risk they could pose to other aircraft and to people on the ground [4]. The Air Line Pilots Association is lobbying for all UAS pilots, including those operating toy-size contraptions near the surface, to meet the same standards as pilots of manned aircraft [5]. And the public is growing increasingly worried about privacy in a world with eyes in the sky that could, in theory, watch and record any outdoor activity [6-7].

These concerns have hindered efforts to integrate sUAS into the national airspace; the FAA’s Notice of Proposed Rulemaking for sUAS has been due out “in the coming months” for four years now [8]. Under growing pressure from industry, Congress recently set a timetable for sUAS

P. B. Voss is with the Picker Engineering Program at Smith College, Northampton, MA 01063 USA. (phone 413-585-4552; fax 413-585-7001; e-mail: [email protected]).

integration as part of the FAA Modernization and Reform Act of 2012 [9]. Public backlash, partially in response to this action, is now leading to restrictive drone-privacy legislation at the federal, state, and local levels [10-13].

This paper raises additional concerns about sUAS and their potential impacts on property rights, privacy, and national security. In doing so, the intent is not to exacerbate the present situation, but to present an alternative framework for moving forward, one that could have substantial benefits for regulatory efficiency and for the civilian UAS industry in the United States.

II. A HISTORICAL PERSPECTIVE ON AIRSPACE

One of the most fundamental questions regarding sUAS policy is who owns the airspace near the ground in which these new aircraft will be operating. While it is well established that the United States Government has “exclusive sovereignty of airspace of the United States” [14-15], just as it has sovereignty over the lands and waters, the ownership of airspace is different question with a long and protracted legal history [16]. For example, is the airspace immediately above private land an integral part of the underlying property, or is it a “public highway” for aircraft? Would a sUAS be trespassing if it flew low through a private backyard without permission, or would the owners of this sUAS, whoever they may be, simply be using public airspace to which they are legally entitled? These questions are critically important, not only on their own merit, but also because long-standing federal statutes generally limit FAA authority to the public domain [17].

Nearly identical questions about the right of manned aircraft to overfly private property consumed the careers of U.S. lawmakers and legal scholars for nearly half a century after the Wright Brothers first flew. The controversy arises from the fact that common law in the United States, and before that in Britain, long followed the maxim Cujus est solum, ejus est usque ad coelum, meaning whoever who owns the soil owns it up to the heavens. Property was understood to include not only the land itself but also the three-dimensional volume extending above it “to the heavens”. Ad coelum was typically invoked to settle disputes such as a roof extending over a property line; the landowner was entitled to remedy for such instances of trespass [18].

The first aircraft flights were therefore at odds with centuries of legal precedent and new questions abounded. Were these aircraft and their occupants trespassing? Should property owners be compensated? At what altitude, if any, were aircraft securely in the public airspace? The early aviation industry was as much limited by this insecure legal

Rethinking the Regulatory Framework for Small Unmanned Aircraft: The Case for Protecting Privacy and Property Rights in

the Lowermost Reaches of the Atmosphere

Paul B. Voss


foundation as it was by rickety technology. Concerned about a growing hodgepodge of state laws, the president of the American Flying Club went so far as to complain “no aeroplane would venture to fly without a lawyer” [19].

The right of aircraft to overfly private land was first addressed at the federal level by the Air Commerce Act of 1926. U.S. lawmakers, unlike their counterparts overseas, were severely constrained by the Fifth Amendment to the Constitution, which prohibits the taking of private property without just compensation. The Air Commerce Act of 1926 therefore carefully avoided the question of airspace ownership by granting the public an easement to use the nation’s “navigable airspace”. This navigable airspace was defined as the airspace above the minimum safe altitudes of flight which, in turn, were to be determined by the Department of Commerce. The minimum safe altitudes were subsequently set at 1000 feet over populated areas and 500 feet elsewhere; below these altitudes, at least in areas more than a few nautical miles from an airport, landowners remained in control of the airspace [20].

This understanding of public airspace and private property was solidified in the landmark 1946 Supreme Court case United States v. Causby [21-22]. In response to WWII bombers flying 67 feet above the Causby home and terrorizing 150 of their chickens to death, the Justices concluded “The airspace is a public highway”, but the landowner “must have exclusive control over the immediate reaches of the enveloping atmosphere.” With deft foresight, the Justices further stated that “…the flight of airplanes, which skim the surface but do not touch it, is as much an appropriation of the use of the land as a more conventional entry upon it.” Subsequent court decisions have consistently set the lower boundary of the public airspace at the FAA’s minimum safe altitudes for flight, which are generally understood to be 500 feet in rural areas and 1000 feet over cities and towns [23-26]. In doing so, the courts have largely deferred to the FAA’s judgment in setting the critical boundary between public and private.1

This view of public and private airspace, however, is not universally accepted. Writing for the two dissenting Justices in United States v. Causby, Justice Black argued “Congress thus declared that the air is free -- not subject to private ownership and not subject to delimitation by the courts” [27]. This minority opinion appears to have gained prominence lately both in Congress and among the UAS industry. For example, the Association for Unmanned Vehicle Systems International (AUVSI) in their “Code of Conduct” for UAS Operations does not acknowledge landowner rights to the airspace at any altitude [28].

2

1 As the FAA has lowered the minimum safe altitude for new types of

aircraft (e.g., helicopters), the Court’s deference has become strained. In Florida v. Riley [25], Justice O’Connor cautioned that “public use of altitudes lower than [400 feet]… may be sufficiently rare that police surveillance from such altitudes would violate reasonable expectations of privacy, despite compliance with FAA air safety regulations.”

Similarly, the FAA Modernization and Reform Act of 2012, which was heavily influenced by AUVSI [29], explicitly allows public-safety sUAS to operate “at altitudes less than 400 feet” without concern for property boundaries [30].

2 The author is a member of AUVSI.

In contrast, long-standing federal statutes that define navigable airspace and place it in the public domain do reserve some airspace near the ground for landowners. These statutes closely follow the Air Commerce Act of 1926 and are contained within Title 49 of the United States Code [31]. They state the following:

• Navigable airspace means airspace above the minimum altitudes of flight prescribed by regulations… including airspace needed to ensure safety in the takeoff and landing of aircraft.

• A citizen of the United States has a public right of transit through the navigable airspace

• The Administrator of the FAA shall develop plans and policy for the use of the navigable airspace…”

The clear meaning of these statutes is that public navigable airspace should arc overhead and intersect the ground at airports and other areas where aircraft take off and land. By notable omission, it can be inferred that Congress never intended for navigable airspace to extend to the ground everywhere in the United States. Furthermore, the FAA was charged to develop “plans and policy for the use of navigable airspace”, but not necessarily for the private property that lies below it.

III. REGULATORY CHALLENGES FOR SMALL UAS

When viewed in historical context, the forthcoming regulations for sUAS appear to be highly problematic. It is nearly certain, for example, that sUAS will be operating below 500 feet and that the FAA intends to promulgate rules and regulations for these low altitudes. It is also likely that such regulation implies that the lowermost reaches are considered navigable and therefore in the public domain [32].

These concerns are compounded by the broadening definition of what constitutes an “aircraft”. According to the federal statutes, an “aircraft means any contrivance invented, used, or designed to navigate, or fly in, the air” [33]. The FAA has been expanding its interpretation of this vague statutory language to classify all flying contrivances, no matter how diminutive, as “aircraft”. Even insect-sized contraptions now require FAA certification if they are to be flown anywhere in the navigable airspace, which now appears to mean anywhere outdoors.

These expanding definitions of “aircraft” and “navigable airspace” deserve careful consideration before they are fully implemented. The following list highlights a few of the more serious issues and potential conflicts.

A. Public Use of Private Property By federal statute, “aircraft” operated by US citizens have

the public right of transit through navigable airspace. The expansion of navigable airspace to the ground could therefore challenge reasonable expectations of privacy and property rights. Miniature unmanned aircraft can already fly in swarms, mimic biological organisms, transmit video at night, and record conversations. The fact that such aircraft


could gain a statutory right of transit through all private property, ostensibly at any altitude and for any purpose, could prove to be highly contentious.

B. Preemption of State and Local Authority The immediate reaches of the airspace are largely

governed by state and local laws, such as those pertaining to zoning, nuisance, and public safety. The operation of unmanned aircraft near to the surface therefore introduces a preemption conflict, at least in any matter that could conceivably interfere with sUAS or endanger persons on the ground. Any attempts by state or local authorities to regulate sUAS noise, trespass, dangerous operation, or privacy invasion could potentially be invalidated. As stated succinctly by the FAA’s Assistant Chief Counsel for Regulations, “Local jurisdictions do not have authority to regulate the use of the navigable airspace or the safety of flight operations and local actions to do so would raise preemption questions.” [34].

This jurisdictional conflict is intensified by the FAA’s statutory mandates, which include deadly serious obligations such as “preventing collision between aircraft and airborne objects” [35]. In the near-surface airspace, hazardous airborne objects and obstructions could potentially include anything from kites, hobby airplanes, and bullets, to utility wires, antennas, and wind turbines. It is also notable that “destruction of an aircraft”, apparently even a small unmanned one, is a federal crime punishable by up to 20 years in prison [36]. While such extreme interpretations of the federal statutes may seem unlikely, it is also difficult to imagine how unmanned aircraft would be excluded from legal protections afforded to all other aircraft in navigable airspace.

C. Burden on FAA Resources The FAA has projected that there could be 10,000 active

sUAS in the national airspace within the next several years and 30,000 by 2030 [37]. In a recent talk to UAS industry proponents, Keith Ballenger, an assistant division manager for safety and certifications at the FAA, stated that “Small unmanned systems, those that weigh less than 50 pounds, are where the FAA will see the bulk of its [UAS] work.” Managing this anticipated growth “…is an area that’s got to be a huge growth area with the FAA” [38]. But in an era of sequestration and furloughs, such growth may come at the expense of programs for manned aircraft and could therefore have adverse affects on aviation safety.

D. National Security Issues Federal regulation that places the near-ground airspace in

the public domain creates a serious new vulnerability in our national security. Imagine, for example, that a small UAS flies within purportedly public airspace just above the treetops and then disappears from view. The landowner would have no way of knowing if this sUAS belongs to the local police department, a package delivery company, a

criminal organization, or a terrorist cell. Remarkably, this low-flying sUAS would also be invisible to government radars because it is shielded by obstacles and hidden among low-altitude aerial clutter such as birds and insects. Thus, opening the lowermost reaches of the airspace to public use creates a conduit for illicit sUAS that neither the government nor landowners can monitor; in such a scenario, the United States would quickly lose the benefit of 300 million citizens watching the unguarded airspace that lies just above the rooftops and below the national radars.

E. Impediments to Research and Innovation Scientists, engineers, educators, and entrepreneurs who work with anything that flies in the air are already being required to follow FAA certification procedures similar to those used for passenger aircraft. Attaining the necessary Certificates of Authorization or Experimental Certificates can take months to years, even for well-proven sUAS airframes and avionics; experimenting with new designs has essentially become illegal for all but the largest companies and universities. And these restrictions on basic research apply to all airborne contraptions, no matter how small and safe, even if operated only centimeters above the ground in a remote area. The only exception is for recreation, in which case anyone, even children, can legally fly sUAS weighing up to 55 pounds almost anywhere in the United States [39-40]. Such inconsistent and ineffective policy arguably threatens U.S. leadership in aviation in the coming years.

IV. AN ALTERNATIVE MODEL FOR REGULATION

Many of these issues could be addressed more effectively using the regulatory framework that has been in place for most of the past century, with one important clarification: public navigable airspace should not expand down to the ground simply because very small UAS can safely fly this low.

This zoned model of airspace [41], in which control of the immediate reaches are vested in the landowner as well as state and local governments, is shown schematically in Figure 1. Here the navigable airspace proper, which is generally considered to be above 300-500 feet altitude, would not change from what is currently envisioned by the FAA; it would continue to be managed for the safety of manned aircraft with UAS of all sizes being integrated only as technology and regulation allow. Many UAS would also be allowed to fly below these altitudes, but only with the permission of the landowner or in exigent circumstances such as a hostage situation; in such cases, navigable airspace and FAA authority would extend to the ground, similar to the way it does now for manned helicopters.

Reinforcing the long-standing paradigm that landowners control the lowermost reaches of the airspace would have some substantial benefits. It would prevent some of the most intrusive uses of sUAS and therefore help to defuse public concerns about privacy. Requiring landowner permission would also eliminate most potential airspace


conflicts near the surface and would reduce the probability that sUAS would be endangered by the everyday activities of landowners. Finally, landowner control of the lowermost airspace would increase the likelihood that unauthorized sUAS would be noticed and reported to authorities.

With this more structured approach to airspace management, it should be possible for the FAA to return to its traditional advisory role in the lowermost airspace, a job it has been doing safely and effectively with model aircraft for over 30 years.3

V. CONCLUSION

It would also be reasonable to assume that the smallest UAS could be operated strictly over private property and below navigable airspace without substantial FAA involvement, much like radio-controlled toys are today [43]. As technology continues to evolve, these micro-sized UAS will become ever more capable and useful to society. Even with the requirement for landowner permission, large potential markets exist in agriculture, aerial photography, systems monitoring, environmental research, education, and public safety. Limited FAA resources would then be available for much more critical safety issues pertaining to manned aircraft and larger UAS in the navigable airspace above.

Nearly seventy years ago, the Supreme Court concluded that ad coelum, the view that ownership of the land extends to the heavens, “has no place in the modern world”. The same decision, in the seminal case of United States v. Causby, also made clear that landowners do retain “exclusive control” of the airspace in the “immediate reaches” above their property [44].

The new regulations being written for sUAS appear to challenge these long-established precedents by converting the near-ground airspace into a public venue for unmanned aircraft. While this expansion could be viewed as a victory for the civilian UAS industry, the cost of increased federal regulation, public backlash, new privacy laws, and potential legal challenges are likely to far outweigh any gains from expanding public airspace to the ground.

A more balanced approach will recognize that sUAS should generally not be operated near the ground without explicit landowner permission. Such recognition has the potential to increase public acceptance of unmanned aircraft, reduce regulatory burdens, and allow civilian sUAS to begin making positive contributions to society.

ACKNOWLEDGMENT The author thanks Smith College for supporting this

research. Elizabeth Cutter Morrow, the first woman president of Smith College, was married to Dwight Morrow, chairman of the Air Board under President Calvin Coolidge. Morrow’s Air Board report was the foundation for the Air

3 Model aircraft accidents have caused a total of five known deaths in the

United States over the past 50 years [42].

Commerce Act of 1926 which established the federal airspace system in the United States.

REFERENCES [1] Congress of the United States, Congressional Budget Office, “Policy

Options for Unmanned Aircraft Systems,” June 2011. [2] Appleby, J., and J. R. Cantor, “Privacy Impact Assessment for the

Robotic Aircraft for Public Safety (RAPS) Project,” DHS/S&T/PIA-026, Department of Homeland Security, Nov. 2012

[3] Beard, R.W. and T.W. McLain, Small Unmanned Aircraft: Theory and Practice, Princeton, NJ, Princeton University Press, 2012, preface, p. xi.

[4] Federal Aviation Administration, “Fact Sheet Unmanned Aircraft Systems (UAS),” July 2011.

[5] Statement of Captain Lee Moak, President Air Line Pilots Association, International, Submitted to the Subcommittee on Aviation, Committee on Transportation and Infrastructure, United States House of Representatives on the FAA Reauthorization act of 2011, Feb 9, 2011.

[6] Stanley, J. and C. Crump, “Protecting Privacy from Aerial Surveillance: Recommendations for Government Use of Drone Aircraft,” New York, American Civil Liberties Union, Dec. 2011.

[7] Villasenior, J., “Will Drones Outflank the Fourth Amendment?” Forbes Magazine, Opinion, Sept. 20, 2012.

[8] United States Government Accountability Office, “Report to Congressional Requesters, Unmanned Aircraft Systems: Federal Actions Needed to Ensure Safety and Expand Their Potential Uses within the National Airspace System,” Washington, D.C., May 2008, p. 34.

[9] FAA Modernization and Reform Act of 2012, Public Law 112-95, Sec. 332, U.S. Government Printing Office, Feb. 2012.

[10] Markey, E., “A bill to amend the FAA Modernization and Reform Act of 2012 to Provide Guidance and Limitations Regarding the Integration of Unmanned Aircraft Systems into United States Airspace, and for Other Purposes,” H.R. 6676 (112th), Introduced Dec. 2012.

[11] Paul, R., “Preserving Freedom from Unwarranted Surveillance Act of 2012,” S. 3287 (112th), Introduced June 2012, died (referred to committee).

[12] Contorno, S., “States Wrestle with Domestic Use of Drones,” Washington Examiner, Mar. 3, 2013.

[13] Hennigan, W.J., “City in Virginia Passes Anti-Drone Resolution,” Los Angeles Times, Feb. 6, 2013.

[14] United States Code, Title 49, § 40103(a)(1) (2013). [15] Elias, B., “Pilotless Drones: Background and Considerations for

Congress Regarding Unmanned Aircraft Operations in the National Airspace System,” Congressional Research Service, R42718, p. 20, Sept. 2012.

[16] Banner, S., Who Owns the Sky: The Struggle to Control Airspace from the Wright Brothers On, Cambridge, MA, Harvard University Press, 2008.

[17] United States Code, Title 49, § 40103 (2013). [18] Banner, S., Who Owns the Sky: The Struggle to Control Airspace

from the Wright Brothers On, Cambridge, MA, Harvard University Press, 2008, pp. 16-20.

[19] ibid., p. 103. [20] ibid., pp. 161-168. [21] United States v. Causby, 328 U.S. 256 (1946). [22] Dolan, A., and R. M. Thompson, “Integration of Drones into

Domestic Airspace: Selected Legal Issues,” Congressional Research Service, R42940, Jan. 2013.

[23] Griggs v. Allegheny County, 369 U.S. 84 (1962). [24] California v. Ciraolo, 476 U.S. 207 (1986). [25] Florida v. Riley, 488 U.S. 445 (1989). [26] Argent v. United States, 124 F. 3d 1277 (1997). [27] United States v. Causby, 328 U.S. 256 (1946). [28] Association for Unmanned Vehicle Systems International,

“Unmanned Aircraft System Operations Industry Code of Conduct”, Arlington, VA, July 2012.

[29] Stone, A., “Drone Lobbying Ramps Up Among Industry Manufacturers, Developers,” Huffington Post, May 25, 2012.


[30] [28] FAA Modernization and Reform Act of 2012, Public Law 112-95, Sec. 903, U.S. Government Printing Office, Feb. 14, 2012.

[31] United States Code, Title 49, § 40102-3 (2013). [32] Les Dorr, Media Specialist, Federal Aviation Administration, “…any

altitudes mandated in the [Federal Aviation Regulations] are considered navigable airspace”, private communication, July, 2012.

[33] United States Code, Title 49, § 40102 (2013). [34] MacPherson, R., “Letter to Mr. Don Marcostica, Executive Director

Colorado Office of Economic Development and International Trade,” Assistant Chief Counsel for Regulations at the Federal Aviation Administration, July 9, 2010.

[35] United States Code, Title 49, § 40103 (2013). [36] ibid., Title 18 USC § 32 (2013). [37] Federal Aviation Administration, “FAA Aerospace Forecast Fiscal

Years 2011–2031, U.S. Department of Transportation Federal Aviation Administration Aviation Policy and Plans,” p 49, March 2011.

[38] Lawrence, C., “Industry watchers ponder future of drones at local conference,” Ventura County Star, March 26, 2013.

[39] Federal Aviation Administration, “Advisory Circular 91-57: Model Aircraft Operating Standards,” Washington, D.C., June 1981.

[40] Federal Aviation Administration, “Interim Operational Approval Guidance 08-01: Unmanned Aircraft Systems Operations in the U. S. National Airspace System,” Washington, D.C., March 2008.

[41] Cummings, J.J, “Ownership and Control of Airspace,” Marquette Law Review, 37(2), pp. 178-179, Fall 1953.

[42] Richard Hanson, Director of Public Relations and Government Affairs, Academy of Model Aeronautics, private communication, July 2012.

[43] Lacher, A. and D. Maroney, “A New Paradigm for Small UAS, MITRE Corporation,” Public Release 12-2840, 2012.

[44] Meltz, R., D.H. Merriam, and R.M. Frank, The Takings Issue: Constitutional Limits on Land Use Control and Environmental Regulation, Washington, D.C., Island Press, 1999, p. 328.

Figure 1. Zoned model of airspace in which UAS would only be allowed onto private property (below 300-500 feet altitude) with permission from the landowner, a warrant from a judge, or in the event of a public emergency. With this safer partitioning of the airspace, it is conceivable that micro-sized UAS could be operated over private property (below navigable airspace) without substantial FAA involvement. A zoned model nearly identical to the one shown here has served the United States well since the dawn of aviation.

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