UNMANNED AIRCRAFT 

SYSTEMS

Use in the National 

Airspace System and the 

Role of the Department of 

Homeland Security 

Statement of Gerald L. Dillingham, Ph.D. 

Director, Physical Infrastructure Issues

Testimony 

Before Subcommittee on Oversight, 

Investigations, and Management, 

Committee on Homeland Security, House 

of Representatives

For Release on Delivery

Expected at 9:30 a.m. EDT

Thursday, July 19, 2012

GAO-12-889T

United States Government Accountability Office

GAO
United States Government Accountability Office

Highlights of GAO-12-889T, a testimony 

before the Subcommittee on Oversight, 

Investigations, and Management, Committee 

on Homeland Security, House of 

Representatives. 

July 19, 2012 

UNMANNED AIRCRAFT SYSTEMS 

Use in the National Airspace and the Role of the 

Department of Homeland Security

Why GAO Did This Study

UAS aircraft do not carry a human 

operator on board, but instead operate 

on pre-programmed routes or by 

following commands from pilotoperated ground stations. An aircraft is 

considered to be a small UAS if it is 55 

pounds or less, while a large UAS is 

anything greater. Current domestic 

uses of UAS are limited and include 

law enforcement, monitoring or fighting 

forest fires, border security, weather 

research, and scientific data collection 

by the federal government. FAA 

authorizes military and non-military 

UAS operations on a limited basis after 

conducting a case-by-case safety 

review. Several other federal agencies 

also have a role or interest in UAS, 

including DHS. In 2008, GAO reported 

that safe and routine access to the 

national airspace system poses 

several obstacles.

This testimony discusses 1) obstacles 

identified in GAO’s previous report on 

the safe and routine integration of UAS 

into the national airspace, 2) DHS’s 

role in the domestic use of these 

systems, and 3) preliminary 

observations on emerging issues from 

GAO’s ongoing work.

This testimony is based on a 2008 

GAO report and ongoing work, and is 

focused on issues related to nonmilitary UAS. In ongoing work, GAO 

analyzed FAA’s efforts to integrate 

UAS into the national airspace, the role 

of other federal agencies in achieving 

safe and routine integration, and other 

emerging issues; reviewed FAA and 

other federal agency efforts and 

documents; and conducted selected 

interviews with officials from FAA and 

other federal, industry, and academic 

stakeholders.

What GAO Found

GAO earlier reported that unmanned aircraft systems (UAS) could not meet the 

aviation safety requirements developed for manned aircraft and posed several 

obstacles to operating safely and routinely in the national airspace system. These 

include 1) the inability for UAS to detect, sense, and avoid other aircraft and airborne 

objects in a manner similar to “see and avoid” by a pilot in a manned aircraft; 2) 

vulnerabilities in the command and control of UAS operations; 3) the lack of 

technological and operational standards needed to guide the safe and consistent 

performance of UAS; and 4) the lack of final regulations to accelerate the safe 

integration of UAS into the national airspace. GAO stated in 2008 that Congress 

should consider creating an overarching body within the Federal Aviation 

Administration (FAA) to address obstacles for routine access. FAA’s Joint Planning 

and Development Office (JPDO) has taken on a similar role. FAA has implemented 

GAO’s two recommendations related to its planning and data analysis efforts to 

facilitate integration.

The Department of Homeland Security (DHS) is one of several partner agencies of 

JPDO working to safely integrate UAS into the national airspace. Since 2005, FAA 

has granted DHS authority to operate UAS to support its national security mission in 

areas such as the U.S. northern and southern land borders. DHS’s Transportation 

Security Administration (TSA) has the authority to regulate security of all modes of 

transportation, including non-military UAS, and according to TSA officials, its aviation 

security efforts include monitoring reports on potential security threats regarding the 

use of UAS. Security considerations could be exacerbated with routine UAS access. 

TSA has not taken any actions to implement GAO’s 2008 recommendation that it 

examine the security implications of future, non-military UAS. 

GAO’s ongoing work has identified several UAS issues that, although not new, are 

emerging as areas of further consideration in light of greater access to the national 

airspace. These include concerns about privacy relating to the collection and use of 

surveillance data. Currently, no federal agency has specific statutory responsibility to 

regulate privacy matters relating to UAS. Another emerging issue is the use of model 

aircraft (aircraft flown for hobby or recreation) in the national airspace. FAA is 

generally prohibited from developing any rule or regulation for model aircraft. The 

Federal Bureau of Investigation report of a plot to use a model aircraft filled with 

plastic explosives to attack the Pentagon and U.S. Capitol in September 2011has 

highlighted the potential for model aircraft to be used for unintended purposes. An 

additional emerging issue is interruption of the command and control of UAS 

operations through the jamming and spoofing of the Global Positioning System 

between the UAS and ground control station. GAO plans to report more fully this fall 

on these issues, including the status of efforts to address obstacles to the safe and 

routine integration of UAS into the national airspace.

Figure 1: Example of a Small UAS (SkySeer) and a Large UAS (Predator)

View GAO-12-889T. For more information, 

contact Gerald Dillingham at (202) 512-2834 

or dillinghamg@gao.gov. 
 

Page 1 GAO-12-889T Unmanned Aircraft Systems

Chairman McCaul, Ranking Member Keating, and Members of the 

Subcommittee:

I appreciate the opportunity to testify before you today on obstacles to 

unmanned aircraft systems (UAS) safe and routine operations in the 

national airspace, the role that the Department of Homeland Security 

(DHS) has in UAS operations, and emerging UAS issues. Many 

stakeholders have exhibited increased interest in UAS for border security 

and disaster assistance, among other uses. Additionally, as combat 

operations in Afghanistan decrease, all of the United States military 

services expect to conduct more UAS training flights across the 

contiguous United States.1

UAS aircraft do not carry a human operator on board, but instead operate 

on pre-programmed routes or by following commands from pilot-operated 

ground stations. These aircraft are also referred to as “unmanned aerial 

vehicles,” “remotely piloted aircraft,” “unmanned aircraft,” or “drones.” The 

term “unmanned aircraft system” is used to recognize that a UAS includes 

not only the airframe, but also associated elements such as a ground 

station and the communications links. UAS are typically described in 

terms of weight, endurance, purpose of use, and altitude of operation. 

Most UAS are considered small, weighing less than 55 pounds; some of 

which fly less than 400 feet above the ground. According to an industry 

association, small UAS are expected to comprise the majority of UAS that 

will operate in the national airspace.

The Federal Aviation Administration (FAA) authorizes military and nonmilitary (academic institutions; federal, state, and local governments 

including law enforcement entities; and private sector entities) UAS 

operations on a limited basis after conducting a case-by-case safety 

review. Only federal, state, and local government agencies can apply for 

a Certificate of Waiver or Authorization (COA); private sector entities must 

apply for special airworthiness certificates in the experimental category. 2

 

1

House Permanent Select Committee on Intelligence, Performance Audit of the 

Department of Defense Intelligence, Surveillance, and Reconnaissance (Washington, DC: 

Apr. 2012).

2

COAs and special airworthiness certifications in the experimental category represent 

exceptions to the usual certification process. FAA examines the facts and circumstances 

of a proposed UAS to ensure that the prospective operator has acceptably mitigated 

safety risks.

 
 

Page 2 GAO-12-889T Unmanned Aircraft Systems

Between January 1, 2012 and July 17, 2012, FAA had issued 201 COAs 

to 106 federal, state, and local government entities across the United 

States, including law enforcement entities as well as academic 

institutions. Additionally, FAA had issued 8 special airworthiness 

certifications for experimental use to four UAS manufacturers. Presently, 

under COA or special airworthiness certification, UAS operations are 

permitted for specific times, locations, and operations. Thus it is not 

uncommon for an entity to receive multiple COAs for various missions. 

Over the years, concerns have been expressed by the Congress and 

other stakeholders that sufficient progress has not been made to integrate 

UAS into the national airspace system. In 2008, GAO reported that safe 

and routine access to the national airspace system poses several 

obstacles. We also stated that Congress should consider creating an 

overarching body within FAA to coordinate federal, academic, and 

private-sector efforts in meeting the safety challenges of allowing routine 

access to the national airspace system. Additionally, we made two 

recommendations to FAA related to its planning and data analysis efforts 

to facilitate the process of allowing UAS routine access to the national 

airspace. We also recommended that DHS assess the security 

implications of routine access. FAA is working toward implementing the 

requirements set forth by its February 2012 reauthorization to accelerate 

UAS integration.3

Several other federal agencies also have a role or interest in UAS, 

including the Department of Homeland Security (DHS), the Department of 

Defense (DOD), and the National Aeronautics and Space Administration 

(NASA).4

 

3

FAA Modernization and Reform Act of 2012, Pub. L. No. 112-95, §§ 332 – 334, 126 Stat. 

11 (2012).

DHS’s Transportation Security Administration (TSA) has 

authority to regulate the security of all transportation modes, including 

non-military UAS, to ensure that appropriate safeguards are in place. 

According to TSA, its aviation security efforts include addressing risks, 

threats, and vulnerabilities related to non-military UAS. In addition, 

According to DHS officials, Customs and Border Protection (CBP) owns 

ten UAS that it operates for its own missions as well as for missions in 

conjunction with other agencies. DOD has successfully used UAS for 

4

Senior executives from these four federal agencies represent the UAS ExCom, whose 

mission is to enable increased and ultimately routine access of federal UAS engaged in 

non-military aircraft operations into the national airspace to support these agencies’ 

operational, training, development, and research requirements.
 

Page 3 GAO-12-889T Unmanned Aircraft Systems

intelligence, surveillance, reconnaissance, and combat missions.5

My statement today discusses 1) obstacles we identified in our previous 

report to the safe and routine integration of UAS into the national 

airspace, 2) DHS’s role in the domestic use of these systems, and 3) 

preliminary observations on emerging issues from our ongoing work 

examining UAS. This statement is based on our 2008 UAS report

While 

many of DOD’s UAS operations currently take place outside of the United 

States, the military services require access to the national airspace to 

conduct UAS training. DOD has also assisted DHS in border security 

missions, including two missions since 2006 where the National Guard 

provided support in four southwestern border states. NASA uses UAS 

primarily for research purposes, such as the Predator B for wildfire 

mapping and investigations as well as an expected arctic mission next 

year on surface sea ice.

6

 

5

GAO, Unmanned Aircraft Systems: Comprehensive Planning and a Results-Oriented 

Training Strategy Are Needed to Support Growing Inventories, 

and 

ongoing work for this subcommittee, the House Committee on 

Transportation and Infrastructure and its subcommittee on Aviation, and 

the Senate Committee on Science, Commerce and Transportation. Our 

ongoing work is focused on issues related to non-military UAS and is 

based on our analysis of FAA’s efforts to integrate UAS into the national 

airspace, the role of other federal agencies in achieving safe and routine 

integration, and other emerging issues. Our preliminary observations are 

based on our review of various FAA and other federal agency efforts and 

documents; and selected interviews with officials from FAA and other 

federal, industry, and academic stakeholders. Our 2008 report contains 

detailed explanations of the methods used to conduct that work. We have 

discussed the information in this testimony with officials from FAA and 

DHS, and incorporated their comments as appropriate. The work on 

which this statement is based was performed in accordance with 

generally accepted government auditing standards. Those standards 

require that we plan and perform the audit to obtain sufficient, appropriate 

evidence to provide a reasonable basis for our findings and conclusions 

based on our audit objectives. We believe that the evidence obtained 

GAO-10-331 (Washington, 

DC: Mar. 26, 2010).

6

GAO, Unmanned Aircraft Systems: Federal Actions Needed to Ensure Safety and 

Expand Their Potential Uses within the National Airspace System, GAO-08-511

(Washington, D.C.: May 15, 2008).
 

Page 4 GAO-12-889T Unmanned Aircraft Systems

provides a reasonable basis for our findings and conclusions based on 

our audit objectives.

Current domestic uses of UAS are limited and include law enforcement, 

monitoring or fighting forest fires, border security, weather research, and 

scientific data collection. UAS have a wide-range of potential uses, 

including commercial uses such as pipeline, utility, and farm fence 

inspections; vehicular traffic monitoring; real estate and construction site 

photography; relaying telecommunication signals; and crop dusting. 

FAA’s long-range goal is to permit, to the greatest extent possible, routine 

UAS operations in the national airspace system while ensuring safety. 

Using UAS for commercial purposes is not currently allowed in the 

national airspace. As the list of potential uses for UAS grows, so do the 

concerns about how they will affect existing military and non-military

aviation as well as concerns about how they might be used.

Domestically, state and local law enforcement entities represent the 

greatest potential use of small UAS in the near term because small UAS 

can offer a simple and cost effective solution for airborne law enforcement 

activities for agencies that cannot afford a helicopter or other larger 

aircraft.7

 

7

FAA generally considers UAS in the two broad categories of “small” and “large,” and has 

used these categories to split its efforts to develop rules that would allow government and 

commercial UAS access to the national airspace. FAA has been developing rules for small 

UAS for several years. Although there is no widely accepted common classification 

system for UAS, an aircraft is considered to be a small UAS if it is 55 pounds or less, while 

a large UAS is anything greater.

For example, federal officials and one airborne law enforcement 

official said that a small UAS costing between $30,000 and $50,000 is 

more likely to be purchased by state and local law enforcement entities 

because the cost is nearly equivalent to that of a patrol car. According to 

recent FAA data, 12 state and local law enforcement entities have a 

Certificate of Waiver or Authorization (COA) while an official at the 

Department of Justice said that approximately 100 law enforcement 

entities have expressed interest in using a UAS for some of their 

missions. According to law enforcement officials with whom we spoke, 

small UAS are ideal for certain types of law enforcement activities. 

Officials anticipate that small UAS could provide support for tactical 

teams, post-event crime scene analysis and critical infrastructure 

photography. Officials said that they do not anticipate using small UAS for 

Background
 

Page 5 GAO-12-889T Unmanned Aircraft Systems

routine patrols or missions that would require flights over extended 

distances or time periods.

FAA has been working with the Department of Justice’s National Institute 

of Justice to develop a COA process through a memorandum of 

understanding to better meet the operational requirements of law 

enforcement entities. While the memorandum of understanding 

establishing this COA process has not been finalized, there are two law 

enforcement entities that are using small UAS on a consistent basis for 

their missions and operations. The proposed process would allow law 

enforcement entities to receive a COA for training and performance 

evaluation. When the entity has shown proficiency in operating its UAS, it 

would then receive an operational COA allowing it to operate small UAS 

for a range of missions. In May 2012, FAA stated that it met its first 

requirement to expedite the COA process for public safety entities. FAA’s 

reauthorization also required the agency to enter into agreements with 

appropriate government agencies to simplify the COA process and allow 

a government public safety agency to operate unmanned aircraft 

weighing 4.4 pounds or less if flown within the line of sight of the operator, 

less than 400 feet above the ground, and during daylight conditions, 

among others stipulations.

In 2008, we reported that UAS could not meet the aviation safety 

requirements developed for manned aircraft and posed several obstacles 

to operating safely and routinely in the national airspace system.

• Sense and avoid technologies. To date, no suitable technology has 

been identified that would provide UAS with the capability to meet the 

detect, sense, and avoid requirements of the national airspace 

system. Our ongoing work indicates that research has been carried 

out to mitigate this, but the inability for UAS to sense and avoid other 

aircraft or objects remains an obstacle. With no pilot to scan the sky, 

UAS do not have an on-board capability to directly “see” other aircraft. 

Consequently, the UAS must possess the capability to sense and 

avoid an object using on-board equipment, or with the assistance of a 

human on the ground or in a chase aircraft,8

 

8

Chase pilots are in constant radio contact with research pilots and serve as an “extra set 

of eyes” to help maintain total flight safety during specific tests and maneuvers. Chase 

pilots monitor certain events for the research pilot and are an important safety feature on 

all research missions.

or by other means, such 

Obstacles to Safe and 

Routine Integration of 

UAS
 

Page 6 GAO-12-889T Unmanned Aircraft Systems

as radar. Many UAS, particularly smaller models, will likely operate at 

altitudes below 18,000 feet, sharing airspace with other vehicles or 

objects. Sensing and avoiding other vehicles or objects represents a 

particular challenge for UAS, because other vehicles or objects at this 

altitude often do not transmit an electronic signal to identify

themselves and, even if they did, many small UAS, do not have 

equipment to detect such signals if they are used and may be too 

small to carry such equipment.

• Command and control communications. Similar to what we previously 

reported, ensuring uninterrupted command and control for UAS 

remains a key obstacle for safe and routine integration into the 

national airspace. Without such control, the UAS could collide with 

another aircraft or crash, causing injury or property damage. The lack 

of dedicated radiofrequency spectrum for UAS operations heightens 

the possibility that an operator could lose command and control of the 

UAS. Unlike manned aircraft that use dedicated radio frequencies, 

non-military UAS currently use undedicated frequencies and remain 

vulnerable to unintentional or intentional interference. To address the 

potential interruption of command and control, UAS generally have 

pre-programmed maneuvers to follow if the command and control link 

becomes interrupted (called a “lost-link scenario”). However, these 

procedures are not standardized across all types of UAS and, 

therefore, remain unpredictable to air traffic controllers who have 

responsibility for ensuring safe separation of aircraft in their airspace.

• Standards. A rigorous certification process with established 

performance thresholds is needed to ensure that UAS and pilots meet 

safety, reliability, and performance standards. Minimum aviation 

system standards are needed in three areas: performance; command 

and control communications; and sense and avoid. In 2004, RTCA, a 

standards-making body sponsored by FAA, established a federal 

advisory committee called the Special Committee 203 (or SC 203), to 

establish minimum performance standards for FAA to use in 

developing UAS regulations.9

 

9

RTCA, formerly the Radio Technical Commission for Aeronautics, is a private, not-forprofit corporation that develops consensus-based performance standards regarding 

communications, navigation, surveillance, and air traffic management system issues. 

RTCA serves as a federal advisory committee, and its recommendations are the basis for 

a number of FAA’s policy, program, and regulatory decisions. 

Individuals from academia and the 

private sector serve on the committee, along with FAA, NASA, and 
 

Page 7 GAO-12-889T Unmanned Aircraft Systems

DOD officials. ASTM International Committee F38 on UAS, an 

international voluntary consensus standards-making body, is working 

with FAA to develop standards to support the integration of small UAS 

into the national airspace.10

• Regulations. FAA regulations govern the routine operation of most 

aircraft in the national airspace system.11

Given the remaining obstacles to UAS integration, we stated in 2008 that 

Congress should consider creating an overarching body within FAA to 

coordinate federal, academic, and private-sector efforts in meeting the 

safety challenges of allowing routine access to the national airspace 

system. While it has not created this overarching body, FAA’s Joint 

Planning and Development Office has taken on a similar role. In addition, 

Congress set forth requirements for FAA in its February 2012 

reauthorization to facilitate UAS integration. Additionally, we made two 

recommendations to FAA related to its planning and data analysis efforts 

to facilitate the process of allowing UAS routine access to the national 

airspace, which FAA has implemented.

However, these regulations 

do not contain provisions to address issues relating to unmanned 

aircraft. As we highlighted in our previous report, existing regulations 

may need to be modified to address the unique characteristics of 

UAS. Today, UAS continue to operate as exceptions to the regulatory 

framework rather than being governed by it. This has limited the 

number of UAS operations in the national airspace, and that limitation 

has, in turn, contributed to the lack of operational data on UAS in 

domestic operations previously discussed. One industry forecast 

noted that growth in the non-military UAS market is unlikely until 

regulations allow for the routine operation of UAS. Without specific 

and permanent regulations for safe operation of UAS, federal 

stakeholders, including DOD, continue to face challenges. The lack of 

final regulations could hinder the acceleration of safe and routine 

integration of UAS into the national airspace.

 

10ASTM International, formerly known as the American Society for Testing and Materials 

(ASTM), is a globally recognized leader in the development and delivery of international 

voluntary consensus standards. ASTM members deliver the test methods, specifications, 

guides and practices that support industries and governments worldwide.

11Title 14, Code of Federal Regulations (14 CFR).
 

Page 8 GAO-12-889T Unmanned Aircraft Systems

DHS is one of several partner agencies of FAA’s Joint Planning and 

Development Office (JPDO) working to safely integrate UAS into the 

national airspace. TSA has the authority to regulate the security of all 

transportation modes, including non-military UAS, and according to TSA 

officials, its aviation security efforts include monitoring reports on potential 

security threats regarding the use of UAS. While UAS operations in the 

national airspace are limited and take place under closely controlled 

conditions, this could change if UAS have routine access to the national 

airspace system. Further, DHS owns and uses UAS.

Security is a significant issue that could be exacerbated with an increase 

in the number of UAS, and could impede UAS use even after all other 

obstacles have been addressed. In 2004, TSA issued an advisory in 

which it stated that there was no credible evidence to suggest that 

terrorist organizations plan to use remote controlled aircraft or UAS in the 

United States. However, the TSA advisory also provided that the federal 

government remains concerned that UAS could be modified and used to 

attack key assets and infrastructure in the United States. TSA advised 

individuals to report any suspicious activities to local law enforcement and 

the TSA General Aviation Hotline.12 Security requirements have yet to be 

developed for UAS ground control stations—the UAS equivalent of the

cockpit.13 Legislation introduced in the 112th Congress would prohibit the 

use of UAS as weapons while operating in the national airspace.14

In our 2008 report, we recommended that the Secretary of Homeland 

Security direct the Administrator of TSA to examine the security 

implications of future, non-military UAS operations in the national 

airspace and take any actions deemed appropriate. TSA agreed that 

consideration and examination of new aviation technologies and 

operations is critical to ensuring the continued security of the national 

airspace. According to TSA officials, TSA continues to work with the FAA 

and other federal agencies concerning airspace security by implementing 

security procedures in an attempt to protect the National Airspace 

 

12Department of Homeland Security, TSA Advisory: Security Information Regarding 

Remote Controlled Aircraft and Unmanned Aerial Vehicles (Washington, DC: Nov. 22, 

2004).

13Additionally, in response to the events of September 11, 2001, entry doors to passenger 

airplane cockpits were hardened to prevent unauthorized entry.

14No Armed Drones Act of 2012, H. R. 5950, 112th Cong. (2012).

Role of the 

Department of 

Homeland Security in 

Domestic UAS Use
 

Page 9 GAO-12-889T Unmanned Aircraft Systems

System. Examples of this collaboration include the coordinated efforts to 

allow access to temporary flight restricted airspace such as those put in 

place for Presidential travel and DHS Security Events. However, to date, 

neither DHS nor TSA has taken any actions to implement our 2008 

recommendation. According to TSA officials, TSA believes its current 

practices are sufficient and no additional actions have been needed since 

we issued our recommendation.

DHS is also an owner and user of UAS. Since 2005, CBP has flown UAS 

for border security missions. FAA granted DHS authority to operate UAS 

to support its national security mission along the United States northern 

and southern land borders, among other areas. Recently, DHS officials 

told us that DHS has also flown UAS over the Caribbean to search for 

narcotics-carrying submarines and speedboats. According to DHS 

officials, CBP owns ten UAS that it operates in conjunction with other 

agencies for various missions. As of May 2012, CBP has flown missions 

to support six federal and state agencies along with several DHS 

agencies. These missions have included providing the National Oceanic 

and Atmospheric Administration with videos of damaged dams and 

bridges where flooding occurred or was threatened, and providing 

surveillance for DHS’s Immigration and Customs Enforcement over a 

suspected smuggler’s tunnel. DHS, DOD, and NASA, are working with 

FAA to identify and evaluate options to increase UAS access in the 

national airspace. DHS officials reported that if funding was available, 

they plan to expand their fleet to 24 total UAS that would be operational 

by fiscal year 2016, including 11 on the southwest border.

The DHS Inspector General reviewed CBP’s actions to establish its UAS 

program, the purpose of which is to provide reconnaissance, surveillance, 

targeting, and acquisition capabilities across all CBP areas of 

responsibility. The Inspector General assessed whether CBP has 

established an adequate operation plan to define, prioritize, and execute 

its unmanned aircraft mission. The Inspector General’s May 2012 report 

found that CBP had not achieved its scheduled or desired level of flight 

hours for its UAS. It estimated that CBP used its UAS less than 40 

percent of the time it would have expected.15

 

15The report made four recommendations intended to improve CBP’s planning of its UAS 

program to address its level of operation, program funding, and resource requirements, 

along with stakeholder needs.
 

Page 10 GAO-12-889T Unmanned Aircraft Systems

Our ongoing work has identified several UAS issues that, although not 

new, are emerging as areas of further consideration in light of the efforts 

towards safe and routine access to the national airspace. These include 

concerns about 1) privacy as it relates to the collection and use of 

surveillance data, 2) the use of model aircraft, which are aircraft flown for 

hobby or recreation, and 3) the jamming and spoofing of the Global 

Positioning System (GPS). 

• Privacy concerns over collection and use of surveillance data. 

Following the enactment of the UAS provisions of the 2012 FAA 

reauthorization act, members of Congress, a civil liberties 

organization, and others have expressed concern that the increased 

use of UAS for surveillance and other purposes in the national 

airspace has potential privacy implications. Concerns include the 

potential for increased amounts of government surveillance using 

technologies placed on UAS as well as the collection and use of such 

data. Surveillance by federal agencies using UAS must take into 

account associated constitutional Fourth Amendment protections 

against unreasonable searches and seizures. In addition, at the 

individual agency level, there are multiple federal laws designed to 

provide protections for personal information used by federal agencies. 

While the 2012 FAA reauthorization act contains provisions designed 

to accelerate the safe integration of UAS into the national airspace, 

proposed legislation in the 112th session of Congress, seeks to limit 

or serve as a check on uses of UAS by, for example, limiting the 

ability of the federal government to use UAS to gather information 

pertaining to criminal conduct without a warrant.16

Currently, no federal agency has specific statutory responsibility to 

regulate privacy matters relating to UAS. UAS stakeholders disagreed 

as to whether the regulation of UAS privacy related issues should be 

centralized within one federal agency, or if centralized, which agency 

would be best positioned to handle such a responsibility. Some 

stakeholders have suggested that FAA or another federal agency 

should develop regulations for the types of allowable uses of UAS to 

specifically protect the privacy of individuals as well as rules for the 

conditions and types of data that small UAS can collect. Furthermore, 

 

16Preserving Freedom from Unwarranted Surveillance Act of 2012, S. 3287, 112th Cong. 

(2012) and Farmer’s Privacy Act of 2012, H.R. 5961, 112th Cong. (2012).

Preliminary 

Observations on 

Emerging UAS Issues
 

Page 11 GAO-12-889T Unmanned Aircraft Systems

stakeholders with whom we spoke said that developing guidelines for 

technology use on UAS ahead of widespread adoption by law 

enforcement entities may preclude abuses of the technology and a 

negative public perception of UAS. Representatives from one civil 

liberties organization told us that since FAA has responsibility to 

regulate the national airspace, it could be positioned to handle 

responsibility for incorporating rules that govern UAS use and data 

collection. Some stakeholders have suggested that the FAA has the 

opportunity and responsibility to incorporate such privacy issues into 

the small UAS rule that is currently underway and in future rulemaking 

procedures. However, FAA officials have said that regulating these 

sensors is outside the FAA’s mission, which is primarily focused on 

aviation safety, and has proposed language in its small UAS Notice of 

Proposed Rulemaking to clarify this.

• Model aircraft. According to an FAA official with whom we spoke and 

other stakeholders, another concern related to UAS is the oversight of 

the operation of model aircraft—aircraft flown for hobby or 

recreation—capable of sustained flight in the atmosphere and a 

number of other characteristics.17 Owners of model aircraft do not 

require a COA to operate their aircraft.18 Furthermore, as part of its 

2012 reauthorization act, FAA is prohibited from developing any rule 

or regulation for model aircraft under a specified set of conditions.19

 

17The 2012 reauthorization act defines the term “model aircraft” to mean an unmanned 

aircraft that is: (1) capable of sustained flight in the atmosphere, (2) flown within visual line 

of sight of the person operating the aircraft, and (3) flown for hobby or recreational 

purposes. 

However, the 2012 reauthorization act also specifies that nothing in 

the act’s model aircraft provisions shall be construed to limit FAA’s 

authority to take enforcement action against the operator of a model 

18FAA’s Advisory Circular 91-57 sets out model aircraft operating standards that 

encourage voluntary compliance with specified safety standards for model aircraft 

operators. 

19This prohibition on FAA model aircraft rules or regulations only applies where the aircraft 

is: (1) flown strictly for hobby or recreational use, (2) operated in accordance with a 

community-based set of safety guidelines and within the programming of a nationwide 

community-based organization, (3) limited to not more than 55 pounds (unless otherwise 

certified through a design, construction, inspection, flight test, and operational safety 

program administered by a community-based organization), (4) operated in a manner that 

does not interfere with and gives way to any manned aircraft, and (5) when flown within 5 

miles of an airport, prior notice of the operation is given to the airport operator and the air 

traffic control tower.
 

Page 12 GAO-12-889T Unmanned Aircraft Systems

aircraft who endangers the safety of the national airspace system.20

The Academy of Model Aeronautics, which promotes the development 

of model aviation as a recognized sport and represents a membership 

of over 150,000, published several documents to guide model aircraft 

users on safety, model aircraft size and speed, and use. For example, 

the Academy’s National Model Aircraft Safety Code specifies that 

model aircraft will not be flown in a careless or reckless manner and 

will not carry pyrotechnic devices that explode or burn, or any device 

that propels a projectile or drops any object that creates a hazard to 

persons or property (with some exceptions).

The Federal Bureau of Investigation report of the arrest and criminal 

prosecution of a man plotting to use a large remote-controlled model 

aircraft filled with plastic explosives to attack the Pentagon and U.S. 

Capitol in September 2011 has highlighted the potential for model 

aircraft to be used for non-approved or unintended purposes.

21

• GPS jamming and spoofing.

The Academy of Model 

Aeronautics also provides guidance on “sense and avoid” to its 

members, such as a ceiling of 400 feet above ground of aircraft 

weighing 55 pounds or less. However, apart from FAA’s voluntary 

safety standards for model aircraft operators, FAA has no regulations 

relating to model aircraft. Currently, FAA does not require a license for 

any model aircraft operators, but according to FAA, the small UAS 

Notice of Proposed Rule Making, under development and expected to 

be published late 2012, may contain a provision that requires certain 

model aircraft to be registered.

22

 

20Pub. L. No. 112-95, § 336, 126 Stat. 11 . 77 (2012).

The jamming and spoofing of the 

communication signal between the UAS and ground control station 

could also interrupt the command and control of UAS operations. In a 

GPS jamming scenario, the UAS could potentially lose its ability to 

determine where it is located and in what direction it is traveling. Low 

21The Academy of Model Aeronautics National Model Aircraft Safety Code allows 

members to fly devices that burn producing smoke and are securely attached to the model 

aircraft and use rocket motors if they remain attached to the model during flight. Model 

rockets may be flown but not launched from a model aircraft.

22GPS spoofing is when counterfeit GPS signals are generated for the purpose of 

manipulating a target receiver’s reported position and time. Todd E. Humphreys, Detection 

Strategy for Cryptographic GNSS Anti-Spoofing, IEEE Transactions on Aerospace and 

Electronics Systems (August 2011).
 

Page 13 GAO-12-889T Unmanned Aircraft Systems

cost devices that jam GPS signals are prevalent. According to one 

industry expert, GPS jamming would become a larger problem if GPS 

is the only method for navigating a UAS. This problem can be 

mitigated by having a second or redundant navigation system 

onboard the UAS that is not reliant on GPS. In addition, a number of 

federal UAS stakeholders we interviewed stated that GPS jamming is 

not an issue for the larger, military-type UAS, as they have an 

encrypted communications link on the aircraft. A stakeholder noted 

that GPS jamming can be mitigated for small UAS by encrypting its 

communications, but the costs associated with encryption may make 

it infeasible. Recently, researchers at the University of Texas 

demonstrated that the GPS signal controlling a small UAS could be 

spoofed using a portable software radio. The research team found 

that it was straightforward to mount an intermediate-level spoofing 

attack but difficult and expensive to mount a more sophisticated 

attack.23

The emerging issues we identified not only may exist as part of efforts to 

safely and routinely integrate UAS into the national airspace, but may 

also persist once integration has occurred. Thus, these issues may 

warrant further examination both presently and in the future. 

Chairman McCaul, Ranking Member Keating, and Members of the 

Subcommittee, this concludes my prepared statement. We plan to report 

more fully this fall on these same issues, including the status of efforts to 

address obstacles to the safe and routine integration of UAS into the 

national airspace. I would be pleased to answer any questions at this 

time.

 

23The presentation “Assessing the Civil GPS Spoofing Threat” by Todd Humphreys, 

Jahshan Bhatti, Brent Ledvina, Mark Psiaki, Brady O’Hanlon, Paul Kintner, and Paul

Montgomery sought to assess the spoofing threat of a small civil UAS. The team built a 

civilian GPS spoofer and tested some countermeasures. They concluded that GPS 

spoofing is a threat to communications security and civil spoofing has not been the focus 

of research in open literature.
 

Page 14 GAO-12-889T Unmanned Aircraft Systems

For further information on this testimony, please contact Gerald L. 

Dillingham, Ph.D., at (202) 512-2834 or dillinghamg@gao.gov. In 

addition, contact points for our Offices of Congressional Relations and 

Public Affairs may be found on the last page of this statement. Individuals 

making key contributions to this testimony include Maria Edelstein, 

Assistant Director; Amy Abramowitz; Erin Cohen; John de Ferrari; Colin 

Fallon; Rebecca Gambler; Geoffrey Hamilton; David Hooper; Daniel Hoy; 

Joe Kirschbaum; Brian Lepore; SaraAnn Moessbauer; Faye Morrison; 

Sharon Pickup; Tina Won Sherman; and Matthew Ullengren.

GAO Contact and 

Staff 

Acknowledgements

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