SMALL UNMANNED 

AIRCRAFT 

SYSTEMS

FAA Should Improve 

Its Management of 

Safety Risks

Report to Congressional Committees

May 2018

GAO-18-110

United States Government Accountability Office
United States Government Accountability Office

Highlights of GAO-18-110, a report to 

congressional committees

May 2018

SMALL UNMANNED AIRCRAFT SYSTEMS

FAA Should Improve Its Management of Safety Risks 

What GAO Found

The Federal Aviation Administration’s (FAA) information on the extent of unsafe 

use of small unmanned aircraft systems (UAS) in the national airspace system is 

limited. Although FAA collects data on several types of safety events involving 

small UAS, the accuracy and completeness of the data are questionable. For 

example, since 2014, pilots and others have reported to FAA over 6,000 

sightings of UAS, often flying near manned aircraft or airports, but FAA officials 

told GAO that FAA cannot verify that small UAS were involved in most of the 

sightings. Officials explained that small UAS are often difficult for pilots to identify 

definitively and typically are not picked up by radar. Such data limitations impede 

the agency’s ability to effectively assess the safety of small UAS operations. FAA 

is taking steps to improve its data. For example, it is developing a web-based 

system for the public to report any sightings of UAS that are perceived to be a 

safety concern and a survey of UAS users on their UAS operational activity. FAA 

did not have time frames for completing these efforts, but according to FAA, 

each of the efforts is underway and at varying stages of development. FAA is 

also evaluating technologies for detecting and remotely identifying UAS, and that 

could improve data on unsafe use.

Examples of Fixed-Wing and Multi-Rotor Small Unmanned Aircraft Systems

Of the five key principles of safety risk management in its policies, FAA—in its 

regulatory efforts related to small UAS—followed two and partially followed three. 

FAA followed the principles of (1) defining appropriate roles and responsibilities 

for safety risk management and (2) describing the aviation system under 

consideration. FAA partially followed the other three principles: (1) analyzing and 

assessing safety risks; (2) implementing controls to mitigate the risks; and (3) 

monitoring the effectiveness of the controls and adjusting them as needed. For 

example, FAA did not consistently analyze and assess safety risks in terms of 

their severity and likelihood; FAA officials told GAO that for some efforts, the 

agency did not have sufficient data to do so. However, for other efforts for which 

FAA did not have sufficient data, the agency made estimates based on expert 

judgment, as allowed under the agency’s safety risk management policy. 

Improved risk management practices would help FAA determine whether 

additional actions are needed to ensure the safety of the national airspace and 

provide FAA and other decision-makers with confidence that FAA is focusing on 

the most critical safety risks posed by small UAS.

View GAO-18-110. For more information, 

contact Heather Krause at (202) 512-2834 or

KrauseH@gao.gov. 

Why GAO Did This Study

Small UAS—unmanned aircraft 

weighing less than 55 pounds, typically 

flown by remote control within sight of 

a ground ”pilot”—are increasingly 

being used for commercial and 

recreational purposes. Congress and 

others have raised questions about the 

extent of unsafe small UAS use and 

FAA’s and other agencies’ efforts to 

address safety risks they pose.

This report examines (1) what 

information is available to FAA about 

the extent of unsafe small UAS use in 

the national airspace, and (2) the 

extent to which FAA’s management of 

safety risks posed by small UAS has 

followed key principles of risk 

management, among other objectives. 

GAO reviewed FAA and other federal 

data on small UAS use from 2014 to

2018, and FAA and industry 

documents. From FAA’s policies that 

apply to its safety oversight, including 

small UAS, GAO identified five key 

safety risk management principles and 

15 supporting requirements, and 

compared them to FAA’s regulatory 

efforts related to small UAS. GAO also 

interviewed FAA officials, as well as 46 

aviation stakeholders, including 

experts and industry groups, selected 

based on their knowledge of small 

UAS safety issues. 

What GAO Recommends

GAO recommends that FAA establish 

a mechanism to ensure that FAA’s 

management of small UAS safety risks 

follows all applicable principles and 

requirements in the agency’s policies.

FAA agreed with GAO’s 

recommendation.
Page i GAO-18-110 Small Unmanned Aircraft Systems

Letter 1

6

10

18

37

47

53

58

59

Background

FAA Lacks Reliable Information about the Extent of Unsafe Use of

Small UAS in the NAS

FAA Is Taking Steps Aimed at Safely Expanding Access of Small

Recreational and Commercial UAS to the NAS

In Selected Efforts Related to Small UAS, FAA Followed Risk

Management Principles to Varying Extents

FAA and DHS Have Taken Some Actions and Coordinated with 

Other Agencies to Address Security Risks Posed by Small UAS

Selected Foreign Countries Are Addressing Safety Risks from

Small UAS Operations

Conclusions 

Recommendation for Executive Action 

Agency Comments 60

Appendix I Policy and Technology Tools Identified 

as Helpful for Addressing Risks Posed 

by Small Unmanned Aircraft Systems 62

Appendix II Objectives, Scope, and Methodology 66

Appendix III Federal Aviation Administration’s 

Coordination Efforts with Industry 

and Academic Stakeholders 75

Appendix IV Statutory and Regulatory Requirements 

for Small Unmanned Aircraft Systems’ 

Operations in Select Countries 77

Appendix V Comments from the Department 

of Transportation 83 

Contents
Page ii GAO-18-110 Small Unmanned Aircraft Systems

Appendix VI GAO Contact and Staff Acknowledgments 85

Tables

Table 1: Selected Federal Departments’ and Agencies’ Recorded 

Incidents of Unmanned Aircraft Systems (UAS) Sightings, 

Various Time Frames in 2013–2017 17

Table 2: The Federal Aviation Administration’s (FAA) Incremental 

Approach for Developing a Regulatory Framework for 

Small Unmanned Aircraft Systems' (UAS) Operations 24

Table 3: Numbers of Actions Taken by the Federal Aviation 

Administration (FAA) to Address Noncompliant or Unsafe 

Use of Small Unmanned Aircraft Systems, from June 7, 

2007 through May 2, 2018 32

Table 4: The National Aeronautics and Space Administration’s 

(NASA) Project Schedule for a Traffic Management 

System for Unmanned Aircraft Systems (UAS) 35

Table 5: GAO’s Assessment of the Extent to Which the Federal 

Aviation Administration’s (FAA) Management of Safety 

Risks Posed by Small Unmanned Aircraft Systems 

Followed Key Risk Management Principles 39

Table 6: Federal Efforts to Research Technologies for Detecting 

Unmanned Aircraft Systems’ (UAS) Operations near U.S. 

Airports 48

Table 7: Comparison of Regulatory Frameworks for Small 

Unmanned Aircraft Systems’ (UAS) Operations in the 

United States and Five Selected Countries 54

Table 8: Comparison of Regulatory Frameworks for Small 

Unmanned Aircraft Systems’ (UAS) Operations in China, 

Germany, Israel, Poland, and South Africa 56

Table 9: Selected Policy and Technology Tools That Have Been 

Identified as Potentially Helping to Address Risks Posed 

by Small Unmanned Aircraft Systems (UAS) in the 

National Airspace System (NAS) 63

Table 10: List of Aviation Industry Stakeholders That GAO 

Interviewed 67

Table 11: Examples of the Federal Aviation Administration’s (FAA) 

Efforts to Coordinate with Industry and Academic 

Stakeholders to Inform the Agency’s Management of 

Safety Risks Posed by Small Unmanned Aircraft Systems’ 

(UAS) Operations 76
Page iii GAO-18-110 Small Unmanned Aircraft Systems

Figures

Figure 1: Examples of Fixed-Wing and Multi-Rotor Small 

Unmanned Aircraft Systems Aircraft 7

Figure 2: The Federal Aviation Administration’s (FAA) Monthly 

Reports of Unmanned Aircraft Systems Sightings, 

February 2014 through April 2018 11

Figure 3: The Federal Aviation Administration’s Registrations of 

Recreational and Commercial Small Unmanned Aircraft 

Systems (UAS) Users, as of October 31, 2017 22

Figure 4: Description of the Federal Aviation Administration’s 

(FAA) Pathfinder 1 Project for Small Unmanned Aircraft 

Systems (UAS) for Operations over People 27

Figure 5: Descriptions of the Federal Aviation Administration’s 

(FAA) Pathfinder Projects 2 and 3 for Small Unmanned 

Aircraft Systems (UAS) for Beyond Line-of-Sight 

Operations 29

Figure 6: Illustration of a Potential Model for the National 

Aeronautics and Space Administration’s (NASA) Concept 

of Operations for the Unmanned Aircraft System Traffic 

Management System 34

Figure 7: The Federal Aviation Administration’s (FAA) Air Traffic 

Organization’s Criteria for Acceptability of Safety Risks 

Posed by Unmanned Aircraft Systems (UAS) 43
Page iv GAO-18-110 Small Unmanned Aircraft Systems

Abbreviations

AMA Academy of Model Aeronautics

ARC Micro Unmanned Aircraft Systems Aviation Rulemaking 

Committee

AUVSI Association for Unmanned Vehicle Systems International 

CAA civil aviation authority 

CNN Cable News Network, Inc.

DHS Department of Homeland Security 

DOD Department of Defense 

DOE Department of Energy 

DOI Department of the Interior 

DOJ Department of Justice 

DOTIG Department of Transportation Office of Inspector General 

EASA European Aviation Safety Agency 

FAA Federal Aviation Administration 

FBI Federal Bureau of Investigation 

ICAO International Civil Aviation Organization 

JARUS Joint Authorities for Rulemaking on Unmanned Systems 

NAS National Airspace System 

NASA National Aeronautics and Space Administration

UAS unmanned aircraft systems

U.K. United Kingdom 

USDA U.S. Department of Agriculture 

UTM Unmanned Aircraft System Traffic Management System

This is a work of the U.S. government and is not subject to copyright protection in the 

United States. The published product may be reproduced and distributed in its entirety 

without further permission from GAO. However, because this work may contain 

copyrighted images or other material, permission from the copyright holder may be 

necessary if you wish to reproduce this material separately.
Page 1 GAO-18-110 Small Unmanned Aircraft Systems

441 G St. N.W.

Washington, DC 20548

May 24, 2018

Congressional Committees

The emergence of unmanned aircraft systems (UAS)1

—commonly 

referred to as “drones”—has potential to provide significant social and 

economic benefits in the United States. Small UAS, those weighing less 

than 55 pounds, are used for a variety of purposes, including taking aerial 

photographs, monitoring crops, and inspecting infrastructure.2 These 

aircraft are typically flown via remote control by a pilot who is located on 

the ground, and the aircraft are generally restricted from operating 

beyond the pilot’s line of sight or operating over people not involved with 

the operation of the aircraft. However, businesses and others are 

interested in expanding small UAS operations for uses such as delivering 

packages and gathering video for news reporting.

Small UAS are defined as “aircraft” in that they operate in the National 

Airspace System (NAS), and therefore the Federal Aviation 

Administration (FAA) has primary oversight responsibility for their safe 

operations. In addition to the restrictions mentioned above, FAA generally 

prohibits small UAS from flying above 400 feet, within certain distances of 

an airport without notifying the airport or obtaining prior authorization from 

its air traffic control, or at night—among other restrictions. However, 

beginning in early 2014, FAA began receiving reports from pilots of 

manned aircraft and others of sightings of UAS operating in a potentially 

unsafe manner, including around manned aircraft and airports, and the 

media have reported that UAS have struck and injured people on the 

ground. In September 2017, a small UAS collided with an Army helicopter 

near Staten Island, New York, and in October 2017, a small UAS collided 

 1

UAS operate by following commands from pilot-operated ground control stations or preprogrammed routes. UAS are also referred to as “unmanned aerial vehicles,” “unmanned 

aerial systems,” “remotely piloted aircraft systems,” “unmanned aircraft,” or “drones.” The 

term “unmanned aircraft systems” is used to recognize that UAS include not only the 

aircraft, but also associated elements such as a ground control station and 

communications links. For simplicity’s sake, throughout this report we use the term “UAS”

to refer to both the entire unmanned aircraft system as well as just the aircraft portion.

2

While this report focuses on small UAS, another category of UAS are those weighing 

greater than 55 pounds. Depending on their size and purpose, they generally fly at higher 

altitudes and are used for the purposes of surveillance, data gathering, and 

communications relay.

Letter
Page 2 GAO-18-110 Small Unmanned Aircraft Systems

with a passenger aircraft in Canada, continuing to raise concerns about 

the harm that could be caused by such collisions.

FAA’s data indicate that the number of small UAS users registered with 

the agency is almost three times the number of registered manned 

aircraft. Further, small UAS are capable of breaching traditional security 

perimeters at critical infrastructure and sensitive sites—such as nuclear 

power plants and at public venues such as sports stadiums—or 

interfering with the operation of other types of transportation, such as 

watercraft. Multiple federal agencies share responsibility for addressing 

security risks to the nation and addressing security issues involving small 

UAS, including the Department of Homeland Security (DHS). FAA 

coordinates with DHS and other federal agencies, as well as state and 

local law enforcement, state aviation agencies, and state and local 

legislative bodies regarding oversight of small UAS. Countries around the 

world face similar challenges in addressing the safety and security risks 

associated with small UAS.

As small UAS are being used more frequently and potentially for more 

purposes and as reports of potentially unsafe UAS encounters with 

people and manned aircraft continue, members of Congress have raised 

questions about the extent of unsafe use and FAA’s efforts to address 

risks. You asked us to examine these issues and progress in integrating 

small UAS into the national airspace. This report examines: (1) what 

information is available to FAA about the extent of unsafe small UAS use 

in the NAS, (2) what steps FAA has taken to safely integrate small UAS 

into the NAS, (3) the extent to which FAA’s management of safety risks 

posed by small UAS has followed key principles of risk management, (4) 

what steps selected federal agencies have taken to address security risks 

posed by small UAS operations in the NAS, and (5) what selected foreign 

countries have done to address safety risks associated with the operation 

of small UAS.3

We reviewed and synthesized available literature and documents related 

to the topic areas, including government and industry reports on efforts to 

address safety and security risks posed by UAS and related FAA policy, 

guidance, plans, and safety-risk management documents. We also 

reviewed relevant statutes and regulations. In addition, we interviewed 

 3

We also examined policy and technological tools that could mitigate the risks associated 

with unauthorized small UAS operations in the NAS and report on selected policies and 

technologies in appendix I.
Page 3 GAO-18-110 Small Unmanned Aircraft Systems

FAA officials and conducted semi-structured interviews and obtained 

documentation from 46 aviation industry stakeholders, including a diverse 

variety of industry groups and associations, aviation companies, aviation 

experts, law firms, and academic institutions. We judgmentally selected 

these stakeholders based on our prior work, literature review, and 

interviews with FAA, other agencies, and aviation industry stakeholders, 

based on their knowledge and involvement with safety and security 

issues related to integration of small UAS in the national airspace. The 

information and viewpoints we obtained from our interviews cannot be 

generalized to all aviation industry stakeholders, but offer insight into 

understanding the issues examined in this report (see app. II for the 

complete list of stakeholders we interviewed).

To examine what information is available to FAA about the extent of 

unsafe small UAS use in the NAS, we obtained and analyzed recent FAA 

data. Specifically, we analyzed (1) reports by pilots of manned aircraft, air 

traffic controllers, and others of UAS sightings from February 2014 

through April 2018; (2) reports by pilots of manned aircraft of near mid-air 

collisions between UAS and manned aircraft from January 2013 through 

April 2018;

4 (3) accidents, incidents, and malfunctions required to be 

reported by certain commercial small UAS operators to FAA from March 

2015 through August 2017;5 and (4) accidents required to be reported by 

commercial small UAS pilots operating under FAA’s regulations from 

August 29, 2016, to May 1, 2018.

6 We also obtained data from a National 

Aeronautics and Space Administration’s (NASA) database—maintained 

by NASA on FAA’s behalf—on reports of potentially unsafe use of UAS 

from January 2005 through August 2016. We reviewed documentation 

about the FAA and NASA data and the systems that produced them and 

found the data to be sufficiently reliable for the purposes of our reporting 

objectives. We assessed the extent to which FAA’s data meets federal 

 4

FAA defines “near mid-air collision” as an incident in which the possibility of a collision 

occurs as a result of an aircraft’s proximity of less than 500 feet to another aircraft or if 

FAA receives a report from a pilot or flight crew member stating that a collision hazard 

existed between two or more aircraft.

5

A commercial small UAS operator is a company responsible for the operation of a small 

UAS. In September 2014, FAA began reviewing and approving applications to allow 

certain UAS operations in the NAS prior to the agency’s implementation of its regulations 

for allowing routine small UAS use in the NAS. FAA requires such operators to submit 

reports of accidents, incidents, and malfunctions to FAA.

6

FAA’s regulations, which took effect on August 29, 2016, require commercial small UAS 

pilots to report any operation of a small UAS involving serious injury to any person or loss 

of consciousness, or certain cases of damage to property. 14 C.F.R. § 107.9.
Page 4 GAO-18-110 Small Unmanned Aircraft Systems

internal control standards related to using quality information to achieve 

objectives.7

We also obtained information on instances of UAS flying over selected 

agencies’ property or facilities or interfering with their operations compiled 

by the Department of Defense (DOD), the Department of Energy (DOE), 

the U.S. Forest Service, the U.S. Park Police, and the Bureau of Prisons. 

We selected these agencies based on our discussions with DHS and on 

literature indicating that UAS incursions may have posed a safety or 

security risk to their facilities or operations. We determined the data to be 

sufficiently reliable for our reporting purposes. We also reviewed studies 

by two non-governmental entities—the Academy of Model Aeronautics 

(AMA)8 and the Center for the Study of the Drone at Bard College—of 

FAA’s reports on UAS of sightings but did not verify these analyses. In 

addition, we interviewed our selected aviation industry stakeholders and 

FAA officials about their perspectives on safety risks posed by small UAS.

To examine the steps FAA has taken to safely integrate small UAS into 

the NAS, we reviewed FAA regulations, education outreach efforts, and 

planning and reporting documents related to UAS integration into the 

NAS. We also obtained FAA’s data on (1) the locations of small UAS 

registrants as of October 31, 2017, and (2) all enforcement actions taken 

against small UAS pilots or operators related to unsafe and unauthorized 

use through May 2, 2018. We reviewed documentation about these data 

and the systems that produced them and interviewed knowledgeable FAA 

officials on how the data are collected, maintained, and verified, and we 

found the data to be sufficiently reliable for the purposes of our reporting 

objectives. We also interviewed officials from NASA and reviewed agency 

documents about the agency’s development and testing of a traffic 

management system for small UAS.

To examine the extent to which FAA’s management of safety risks posed 

by small UAS has followed key principles of risk management, we 

identified FAA’s risk management practices related to small UAS and 

compared these practices to key risk-management principles in FAA’s 

policy. We selected FAA efforts that involved development of regulations 

 7

GAO, Standards for Internal Control in the Federal Government, GAO-14-704G 

(Washington, D.C.: Sept. 10, 2014).

8

AMA, founded in 1936, is the largest model aviation association and represents those 

who fly model aircraft for recreation and educational purposes.
Page 5 GAO-18-110 Small Unmanned Aircraft Systems

for small UAS or issuing waivers or exemptions to those regulations or 

other aviation regulations. We identified the risk management principles 

based on our review of FAA’s policy on safety risk management, from 

which we identified five key principles and 15 specific requirements that 

support those principles.9 Federal internal control standards and the 

International Organization for Standardization’s Risk Management—

Principles and Guidelines include standards, principles, and guidelines 

that are similar to several of the principles and guidelines in these FAA 

policies.10

To examine steps that selected federal agencies have taken to address 

security risks posed by small UAS operations in the NAS, we obtained 

and reviewed documents related to security risks posed by small UAS 

from FAA and other selected federal agencies including DHS, DOD, 

DOE, Department of Justice (DOJ), Department of the Interior (DOI), and 

U.S. Department of Agriculture (USDA). We also obtained and reviewed 

documents from FAA and the other federal departments and agencies 

related to coordination on managing security risks from small UAS, as 

well as interviewed appropriate department and agency officials.

To describe actions that have been taken by selected foreign countries to 

address safety risks associated with the operation of small UAS, we 

reviewed publicly available information and interviewed FAA officials 

about countries that have developed a regulatory framework for ensuring 

safe operations of small UAS in their respective domestic airspace. We 

also interviewed aviation industry stakeholders about their perspectives 

on lessons that could be learned from other countries’ experiences. We 

selected five countries—Australia, Canada, France, Japan, and the 

United Kingdom (U.K.)—that are leaders in the development of a 

framework for the safe and secure operation of small UAS in their 

respective domestic airspaces.11 We reviewed each country’s regulations 

and policies pertaining to small UAS operations. We interviewed officials 

for the civil aviation authorities (CAA)—foreign countries’ counterpart to 

 9

The policy applies to all of FAA’s operational and program functions when making 

planned changes to the NAS and when potential and previously unidentified hazards and 

ineffective safety risk controls are discovered. See FAA, Safety Risk Management Policy, 

Order No. 8040.4A (Washington, D.C.: April 30, 2012).

10See GAO-14-704G and International Organization for Standardization, Risk

Management—Principles and Guidelines, ISO 31000:2009(E) (Geneva: Nov. 15, 2009).

11See GAO, Unmanned Aerial Systems: FAA Continues Progress toward Integration into 

the National Airspace, GAO-15-610 (Washington, D.C.: July 2015).
Page 6 GAO-18-110 Small Unmanned Aircraft Systems

FAA—of four of the selected countries and obtained written responses 

from the fifth and obtained and verified information regarding their 

statutes and regulations, as well as discussed the countries’ approach to 

managing the safety risks associated with small UAS. To expand our 

coverage beyond the initial five countries, we selected an additional five 

countries—China, Germany, Israel, Poland, and South Africa—based on 

geographical location for diversity in our selections, membership standing 

with the Joint Authorities for Rulemaking on Unmanned Systems 

(JARUS),12 and having UAS regulations in place. For these countries, we 

relied primarily on a study by the Law Library of Congress13 and also 

reviewed documentation on their regulations and policies. The information 

on the foreign countries we reviewed cannot be generalized to other 

foreign countries, but offers insight into understanding the issues 

examined in this report. We did not independently verify this information 

with any CAA or government. See appendix II for further details on our 

scope and methodology.

We conducted this performance audit from October 2015 through May 

2018 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 

the evidence obtained provides a reasonable basis for our findings and 

conclusions based on our audit objectives.

The small UAS market in the United States has grown substantially in the 

last 10 years, in part, due to advancements in the technology for small 

UAS using multiple rotor blades (multi-rotor) to operate and control them. 

Today, small UAS are being manufactured in large quantities by various 

companies and small multi-rotor UAS are popular among commercial and 

recreational users. These aircraft are relatively easy to control, have the 

ability to hover, and are reasonably affordable. Their platforms commonly 

feature cameras, and they have given rise to companies using small UAS 

for providing videography services. The ability to hover makes this design 

highly flexible and adaptable, with commercial uses including aerial 

 12Established in 2007, JARUS is a group of aviation experts from 50 countries, as well as 

the European Aviation Safety Agency (EASA), working to recommend a single set of 

technical, safety, and operational requirements for the safe operation of UAS.

13Law Library of Congress, Regulation of Drones (April 2016).

Background
Page 7 GAO-18-110 Small Unmanned Aircraft Systems

photography, infrastructure inspection, and agricultural crop surveys. In 

addition, insurance companies and government agencies are increasingly 

utilizing small UAS to survey property and infrastructure damage from 

floods and other catastrophic events. During such events, including in the 

recent hurricanes affecting parts of the southern United States, 

emergency responders have also used small UAS to assist with search 

and rescue missions. In addition, several media outlets operated small 

UAS over affected areas to provide news coverage to local residents and 

the nation about flooding and damage in the areas. There are also fixedwing small UAS, which have greater range and endurance than small 

multi-rotor UAS, and are designed for being operated beyond the visual 

line of sight of the pilot, like inspecting pipeline and rails and monitoring 

crops.14 Some companies are interested in using multi-rotor small UAS to 

do a variety of activities, such as to deliver packages to homes and 

businesses, to conduct roof inspections, or for surveying and mapping 

land. FAA estimated the small UAS fleet in the United States totaled 

around 1.2 million in 2017—used for recreational and commercial 

purposes—and projected the fleet will total around 2.9 million in 2022.

Figure 1 shows examples of fixed-wing and multi-rotor small UAS aircraft.

Figure 1: Examples of Fixed-Wing and Multi-Rotor Small Unmanned Aircraft Systems Aircraft

 14Beyond the visual line of sight refers to operations that take the UAS farther than the 

pilot’s or any other participating visual observer’s direct vision of the UAS, with vision 

unaided by any device other than corrective lenses.
Page 8 GAO-18-110 Small Unmanned Aircraft Systems

According to FAA, small UAS present some risks and hazards by 

operating in the NAS with manned aircraft. For instance, according to 

FAA, the unmanned nature of small UAS operations raises two unique 

safety concerns that are not present in manned-aircraft operations: 

• the pilot of the small UAS, who is physically separated from it 

during flight, may not have the ability to see manned aircraft in the 

air in time to prevent a mid-air collision, and 

• the pilot of the small UAS could lose control of it due to a failure of 

the communications link between the small UAS and the pilot’s 

handset for controlling the UAS. 

Small UAS are easy to purchase and fly in the NAS. This ease raises 

myriad safety and security concerns in the United States. FAA has a 

major role with regard to the operation of all aircraft, including UAS, in the 

NAS. Safety risks related to the use of small UAS include the potential for 

unintentional collisions between a small UAS and a manned aircraft or 

other objects, causing damage to property, or injury or death to persons. 

FAA’s UAS Integration Office (located in the Office of Aviation Safety) 

seeks to integrate UAS operations into the NAS while ensuring the safety 

of the public and integrity of the airspace. Its efforts, in part, include 

promulgating regulations, researching and testing technology, and 

ensuring compliance with guidelines and regulations.15 In addition, the 

UAS Integration Office coordinates across various offices within the 

agency on UAS-related issues.

The FAA Modernization and Reform Act of 2012 (2012 act)16 directed 

FAA to develop a comprehensive plan to safely accelerate the integration 

of UAS into the NAS and to issue a regulation that allows operations of 

small UAS in the NAS. However, the 2012 act prohibited FAA from 

 15FAA is also responsible for providing safe and efficient air-traffic control services in the 

NAS.

16FAA Modernization and Reform Act of 2012, Pub. L. No. 112-95, 126 Stat. 11 (2012).
Page 9 GAO-18-110 Small Unmanned Aircraft Systems

promulgating any new regulations for recreational small UAS.17 In 

response to a related requirement in the 2012 act, in November 2013, 

FAA issued a road map for integrating UAS into the NAS. This road map

included a plan for developing a regulatory framework for small UAS 

operations inside the United States and for expanding UAS’s uses. Since 

2012, the technology for small UAS has been rapidly developing and, as 

we reported in July 2015, FAA had made progress in integrating UAS into 

the air system but had struggled to keep pace.18

Further, FAA and other federal agencies have faced significant 

challenges related to potential security risks. Since 2012, incidents have 

raised concerns over potential security threats posed by small UAS’s

being used to target critical infrastructure and sensitive areas such as 

commercial and government aircraft and watercraft, military bases, 

nuclear facilities and power plants, electricity facilities, government 

buildings and installations, prisons, and sports stadiums. For instance, in 

January 2015, a small UAS crashed on the White House grounds. Other 

risk scenarios include the prospect of hackers “spoofing” a UAS 

communications signal and taking over the controls, potentially leading to 

a crash or using the aircraft to perform malicious acts. Multiple federal 

agencies—including DHS, DOD, and the Federal Bureau of Investigation 

(FBI)—share responsibility addressing security risks to the nation and for 

security issues related to small UAS.

19 The FAA Extension, Safety, and 

Security Act of 2016 (2016 act) also outlined several provisions for FAA 

 17The law defined model aircraft (which this report refers to as recreational small UAS) as 

unmanned aircraft that are (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. The operation of the aircraft must also meet the following 

conditions: (1) the aircraft is flown strictly for hobby or recreational use; (2) the aircraft is 

operated in accordance with a community-based set of safety guidelines and within the 

programming of a nationwide community-based organization; (3) the aircraft is 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) the aircraft is 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, the pilot of the 

aircraft provides the airport operator and the airport air traffic control tower with prior 

notice of the operation. FAA Modernization and Reform Act of 2012, § 336(c).

18See GAO-15-610.

19DHS has primary responsibility for protecting critical infrastructure. DOD, under the 

National Strategy for Aviation Security, has primary responsibility for defense of the 

national airspace system. DOJ, acting through FBI, is charged with preventing and 

protecting against federal crimes or threats to the national security that could be facilitated 

by UAS. FAA coordinates with DHS, DOD, DOJ, and other federal agencies.
Page 10 GAO-18-110 Small Unmanned Aircraft Systems

and other federal agencies, with industry collaboration, for addressing 

safe integration and security threats of civil UAS’s operating into the 

NAS.20 At the same time, an increasing number of states and local 

communities have passed laws banning or restricting the use of small 

UAS—in many cases related to privacy and criminal penalties for UAS 

misuse.

The issue of safe and secure small UAS operations is not limited to the 

United States. As discussed later in this report, the International Civil 

Aviation Organization (ICAO)21 and JARUS are each taking steps to aid in 

the establishment of guidance and standards for UAS safety and 

integration. As a member of ICAO, the United States has agreed to 

conform to international standards and recommended practices, including 

for UAS. Many foreign countries are also experiencing an increase in 

small UAS use, and some countries’ CAAs have already established 

regulations and guidelines for operating commercial and recreational 

small UAS.

From February 2014 through April 2018, FAA collected 6,117 reports of 

sightings of potentially unsafe use of UAS. According to FAA officials, the 

large majority of reports are from pilots who generally submit statements 

of possible UAS sightings or encounters to FAA’s air traffic control 

facilities, while some reports are submitted by the general public, law 

enforcement, air traffic controllers, and others. The reports typically 

involve sightings of UAS operating around airports or airborne manned 

aircraft, and not collisions. Even so, such UAS could be at heightened risk 

 20FAA Extension, Safety, and Security Act of 2016, Pub. L. No. 114-190, 130 Stat. 615 

(2016).

21ICAO is the international body that, among other things, promulgates international 

standards and recommends practices in an effort to harmonize global aviation standards.

FAA Lacks Reliable 

Information about the 

Extent of Unsafe Use 

of Small UAS in the 

NAS

FAA Has Collected 

Thousands of Reports of 

Potentially Unsafe Use of 

UAS, but Most of These 

Reports Offer Limited 

Information
Page 11 GAO-18-110 Small Unmanned Aircraft Systems

of colliding with manned aircraft, and some pilots reported maneuvering 

their aircraft to avoid the UAS. Such maneuvers can increase the risk of 

the pilot losing control of their aircraft or cause injury to crew members or 

passengers. The number of reported sightings increased about five-fold 

from 233 in 2014 to 1,218 in 2015, and increased by another 51 percent 

in 2016 to 1,840 (see fig. 2). The 2,185 reported sightings in 2017 

represented a 19 percent increase over the number reported in 2016.

According to FAA, the risk of potentially unsafe operations would be 

expected to increase as more UAS enter the NAS.

Figure 2: The Federal Aviation Administration’s (FAA) Monthly Reports of Unmanned Aircraft Systems Sightings, February 

2014 through April 2018

However, the extent that these reports represent actual incidents of 

unsafe use is unclear, for the following reasons:

• FAA told us that most of the reports cannot be verified because a 

small UAS typically is not detected by radar, the small UAS pilot is 

usually not identified, or the small UAS or other physical evidence is 

not recovered. FAA and some aviation industry stakeholders also told 

us that the reliability of many of the reports is questionable; FAA 

explained that this is because pilots can have difficulty positively 

identifying objects as small UAS, given their small size, their distance 

from the observed position, the speeds at which a manned aircraft 
Page 12 GAO-18-110 Small Unmanned Aircraft Systems

and a UAS are operating, or the various factors competing for the 

pilot’s attention.

• FAA officials told us the agency generally does not attempt to make a 

determination on the validity of the UAS reports that are received, or 

to otherwise investigate, and stores all of the information provided in a 

tracking database. One agency official noted that the reports often do 

not contain sufficient information to enable FAA to follow up and 

conduct investigations.

• FAA also told us that some of the reports, despite the reporting pilots’ 

concerns, may have involved UAS operating in a safe and authorized 

manner.

• FAA has also stated that although its sightings data includes several 

reports of pilots claiming UAS strikes on their manned aircraft, 

investigations have found that instead of UAS, the reported collisions 

involved either birds, impacts with other items, or structural failure not 

related to colliding with a UAS.

Although FAA has not categorized or made distinctions about which of 

the reports may have potentially led to an unsafe or hazardous situation, 

such as a near mid-air collision, two nongovernmental entities reviewed 

some of FAA’s reports of sightings and came to differing conclusions 

regarding the potential extent of unsafe use:

• AMA analyzed FAA’s reports of sightings for the period November 13, 

2014, to August 20, 2015, and concluded that about 4 percent of the 

reports involved near misses.22 AMA classified a report as a nearmiss if the report narrative contained one of the terms “near miss,” 

“near collision,” or “NMAC” (near mid-air collision), or some other term 

that indicated a potential near miss.

• In contrast, two researchers at the Center for the Study of the Drone 

at Bard College analyzed largely the same reports and concluded that 

about 36 percent of the reports involved close encounters between 

UAS and manned aircraft.23 The higher rate reflects the Center’s use 

 22Academy of Model Aeronautics, A Closer Look at the FAA’s Drone Data (Muncie, Ind.: 

Sept. 14, 2015). 

23The researchers analyzed reports that dated from December 17, 2013, through 

September 12, 2015, in which the majority were the same FAA reports that AMA 

analyzed. The remaining reports that were analyzed were DOI reports. See Arthur Holland 

Michel and Dan Gettinger, Drone Sightings and Close Encounters: An Analysis, Center for 

the Study of the Drone at Bard College (Annandale-on-Hudson, New York: Dec. 11, 

2015).
Page 13 GAO-18-110 Small Unmanned Aircraft Systems

of broader criteria for classifying an incident as a close encounter, 

namely, the incident report indicated that a UAS came within 500 feet 

of a manned aircraft, that the pilot of the manned aircraft used 

descriptive language indicating that the UAS came dangerously close 

to the manned aircraft, or that the pilot of the manned aircraft took 

evasive action.

On FAA’s behalf, NASA also collects reports of potentially unsafe use of 

UAS, but many of the reports cannot be verified.24 From January 2005 

through August 2016, NASA received 246 reports of safety incidents 

involving UAS; 202 of these incidents occurred since 2014. Of the 246 

incidents, 172 were reported by the pilot of a manned aircraft, 38 were 

reported by the pilot of a UAS, 32 were reported by an air traffic 

controller, and 4 were reported by an observer.

FAA also reviews reports of accidents, incidents, and malfunctions 

submitted to the agency by commercial small UAS operators. Only 

commercial entities whose use of small UAS was authorized by FAA 

under a transitional process prior to the implementation of the agency’s 

small UAS regulations were required to report each of those types of 

events.25 The reports covering the period from March 2015 through 

August 2017 included 98 events where damage resulted to the UAS and 

one accident that resulted in an injury.26 FAA officials told us it would be 

impossible to know if operators have reported all of their accidents and 

incidents; therefore, the data may not be complete. Since August 29, 

2016, when FAA’s small UAS regulations took effect, FAA has required 

commercial pilots of small UAS to report any operation involving serious 

injury to any person or loss of consciousness, or certain cases of damage 

 24In support of an FAA aviation safety reporting program, NASA collects and analyzes 

reports of aviation safety incidents so that FAA, NASA, and aviation industry stakeholders 

can take actions to lessen the likelihood of aviation accidents. The reports are submitted 

voluntarily and confidentially by pilots, air traffic controllers, and others, who receive 

immunity from FAA enforcement actions under certain conditions. NASA, rather than FAA, 

administers the system so that the identity of the reporting party remains unknown to FAA.

25As required under section 333 of the 2012 act, in September 2014, FAA began 

approving applications to allow certain UAS operations in the NAS under a transitional 

process prior to the implementation of its regulations for allowing routine small UAS use in 

the NAS. Under this transitional process, which is described in more detail later, approved 

operators were required to report their accidents, incidents, and malfunctions to FAA for 

the duration of their approved operations—typically 2 years.

26According to an FAA official, there is a lag time for small UAS operators to report 

information to FAA. The data that FAA provided to us was the most recent reporting 

information that was available as of October 2017.
Page 14 GAO-18-110 Small Unmanned Aircraft Systems

to property.27 Through May 1, 2018, FAA had confirmed two reports of 

accidents, one of which resulted in minor property damage and the other 

resulted in a person losing consciousness. In addition, in December 2017, 

the National Transportation Safety Board completed an investigation of a 

collision between a small UAS and a U.S. Army helicopter near Staten 

Island, New York, in which the helicopter sustained minor damage and 

the UAS was destroyed.

FAA officials told us that they are aware that the agency’s data on 

potential unsafe use of small UAS have limitations. Nevertheless, FAA 

uses these data in monitoring the safety of small UAS operating in the 

NAS and in managing risks they pose. FAA policy requires the agency to 

collect and analyze operational data to assess the safety of the NAS and 

manage safety risks.28 Further, federal internal control standards state 

that an agency’s management should identify the information 

requirements needed to achieve its objectives and address risks. They 

further state that management should obtain data from reliable sources 

based on the identified information requirements and that such data 

should be reasonably free from error and bias and faithfully represent 

what they purport to represent.

FAA is making some efforts to improve its data on small UAS operations 

and safety events. As described in more detail later in this report, FAA is 

in the middle stages of implementing its plan for integrating UAS into the 

NAS. FAA’s fiscal year 2018 UAS implementation plan includes efforts to 

improve FAA’s data on the safety of small UAS operations. More 

specifically, the plan calls for FAA to:

• identify safety data to be collected on UAS accidents and 

incidents;

• develop a web-based system for the public to report any sightings 

of UAS that are a safety or privacy concern;

• survey UAS users to determine the number of UAS operations in 

the NAS and obtain other information on UAS activity to enable 

FAA to anticipate and meet demand for NAS facilities and 

 27As discussed later in more detail, FAA’s regulations on small UAS operations—codified 

at 14 C.F.R. §§ 107.1-107.205—took effect on August 29, 2016, and replaced FAA’s 

transitional process for authorizing commercial use.

28FAA, Safety Management System, Order No. 8000.369A (Washington, D.C.: May 8, 

2013).
Page 15 GAO-18-110 Small Unmanned Aircraft Systems

services, assess the impact of regulatory changes on the UAS 

fleet, and implement measures to assure safe integration of UAS 

in the NAS.

While FAA’s plan did not include specific time frames for completing 

these efforts, according to FAA, each of the efforts is under way and at 

varying stages of development and implementation.

In August 2016, FAA announced the creation of a team of industry and 

government stakeholders, which is charged with analyzing safety data 

and developing recommendations to FAA on non-regulatory approaches 

for enhancing safety. The team’s initial efforts include:

• helping FAA develop the survey of UAS users described above, 

• developing a system to enable UAS operators to self-report 

hazardous situations anonymously, and 

• having a small group of aviation industry members volunteer flight 

data from UAS operations to examine the benefits of analyzing 

different datasets.

In addition, although the primary purpose is not to improve FAA’s data on 

UAS safety, FAA is undertaking two efforts to evaluate technologies that 

FAA officials told us could improve the data. First, as discussed in more 

detail later, FAA is evaluating technologies for detecting unauthorized 

UAS operating at or near airports. FAA plans to use the results of its 

evaluation to develop recommendations for standards that will guide the 

selection of UAS detection systems for airports nationwide. Second, as 

discussed in more detail later and in appendix III, FAA is evaluating 

technologies for UAS to broadcast identification information that would 

allow FAA, law enforcement, homeland defense, and national security 

agencies to track UAS. FAA is in the early stages of developing a rule on 

such identification technology.

While FAA’s current data provide some limited insight into the safety of 

small UAS operations in the NAS, improving the accuracy and 

completeness of information on small UAS operations and safety events 

could improve the agency’s ability to understand the extent of unsafe 

uses of small UAS in the NAS. Without this information, FAA is limited in 

its ability to oversee how safely small UAS are being integrated into the 

NAS, including taking corrective actions to reduce the level of unsafe use 

and identifying new safety hazards posed by small UAS operations.
Page 16 GAO-18-110 Small Unmanned Aircraft Systems

Several federal agencies have recorded multiple instances of UAS flying 

over their property or facilities or interfering with their operations (see 

table 1). Officials from several of the agencies told us that they are 

confident that the reports are valid because, for example, the reporting 

personnel on the ground were able to distinguish the UAS from manned 

aircraft or flying animals or the agency was able to contact the pilot of the 

UAS. In contrast, as discussed above, FAA officials told us the agency is 

generally not able to make a determination on the validity of its sightings 

reports.

Some Federal Agencies 

Other Than FAA Have 

Compiled Reports That 

Indicate UAS Might Have 

Posed Risks to Their 

Facilities or Operations
Page 17 GAO-18-110 Small Unmanned Aircraft Systems

Table 1: Selected Federal Departments’ and Agencies’ Recorded Incidents of Unmanned Aircraft Systems (UAS) Sightings, 

Various Time Frames in 2013–2017

U.S. 

department 

or agency

Time frame 

of recorded 

incidents

Number of

recorded 

incidents

Information related 

to recorded 

incidents

Department 

of Defense

January 2015 through

December 

2016

128 At a March 2017 Congressional hearing, a Department official 

testified that unauthorized UAS flights over Navy and Air Force 

installations represent a growing threat to the safety and 

security of nuclear weapons and personnel. Department 

officials told us that the Department’s work on technology 

improvements to enable pilots to detect and track small UAS 

when they are in close proximity to manned aircraft could lead 

to enhancements in the reliability and detail of sightings 

reports.

Department 

of Energy

August 1, 2013, through

October 27, 

2016

25 Department officials told us that these incidents were not 

considered to pose an immediate threat to any of the involved 

facilities or employees and that the reasons for these incidents 

are unknown.

U.S. Forest 

Service

June 22, 2015, through

September 7, 

2016

59 Service officials told us the recorded incidents involved a UAS 

interfering with wildfire fighting operations.a Firefighting 

operations were adversely affected in 32 of the 59 incidents, 

e.g., an aircraft was shut down or sent away from the affected 

area.

U.S. Park 

Police

January 2013 through

mid-January 

2016

47 The agency made contact with the UAS pilot in 37 of the 47 

incidents and issued citations in 19 of those incidents.b The 

Service is concerned that UAS operating in National Parks 

could endanger park visitors, facilities, or wildlife and has 

largely banned launching, landing, or operating a UAS from or 

in the National Park system, with certain exemptions.

Bureau 

of Prisons

November 2015 through 

December 2017

7 Agency officials told us in each instance, individuals attempted 

to introduce contraband inside a federal prison.

Source: GAO summary of departments’ and agencies’ information. | GAO-18-110

a

In more than half of the recorded incidents, the wildfire fighting operations were either managed by 

the Forest Service or co-managed by it and one or more other state or federal agencies. A service 

official told us that in the other incidents, the Forest Service may have provided resources in support 

of the operations.

b

The incidents included only sightings of UAS in areas of primary jurisdiction of the Park Police 

located within the National Capital Region, the Park Police New York Field Office, and the Park Police 

San Francisco Field Office.
Page 18 GAO-18-110 Small Unmanned Aircraft Systems

FAA has taken steps aimed at safely expanding both 1) recreational UAS 

use, by developing guidelines and educating and registering users and 2) 

commercial UAS use, initially by authorizing commercial small UAS 

operators on a case-by-case basis, and subsequently by allowing UAS to 

operate routinely in the NAS under various limitations. FAA has plans to 

further expand commercial use of UAS by allowing operations over 

people and out of users’ line of sight, among other expanded activities, 

until UAS are fully integrated into the NAS. To supplement this regulatory 

effort, FAA is collaborating with NASA on determining the feasibility of 

developing a system to manage UAS traffic. Additionally, FAA may have 

opportunities to explore other new technologies to support full integration 

of small UAS into the NAS.

FAA is legally prohibited from promulgating any new regulations for 

recreational small UAS users.29 In its Interpretation of the Special Rule for 

Model Aircraft (i.e., recreational small UAS), FAA clarified its position that 

recreational small UAS users must satisfy criteria established in the law in 

order to be exempt from future rulemaking.30 In September 2015, FAA 

also issued additional guidelines that reflect current law governing 

recreational use of unmanned aircraft.31 These guidelines encouraged 

pilots to, among other things, operate recreational small UAS at or below 

400 feet above ground level, not interfere with and give way to manned 

aircraft, and give the airport operator or control tower advanced notice 

when flying within 5 miles of an airport. Although FAA cannot require 

recreational users to comply with certain aspects of these guidelines, 

such users must meet statutory requirements of a recreational small UAS, 

 29FAA Modernization and Reform Act of 2012, § 336.

30Interpretation of the Special Rule for Model Aircraft, 79 Fed. Reg. 36,172 (June 25, 

2014).

31FAA, Model Aircraft Operating Standards, AC No. 91-57A, September 2, 2015. 

FAA Is Taking Steps 

Aimed at Safely 

Expanding Access of 

Small Recreational 

and Commercial UAS 

to the NAS

FAA Has Taken Steps to 

Promote Safe 

Recreational and 

Commercial Use of Small 

UAS in the NAS

Guidelines
Page 19 GAO-18-110 Small Unmanned Aircraft Systems

follow the guidelines of a community-based organization, and refrain from 

endangering the safety of the NAS.

In December 2015, FAA also issued guidelines to local, state, and federal 

law enforcement agencies on how to respond to unsafe use, including 

when and how to notify FAA. FAA also encourages members of the public 

to notify local law enforcement when they observe unsafe UAS use. For 

instance, on FAA’s website, the public is advised to call local law 

enforcement if a UAS crashes in their yard, hurts someone, or damages 

property. The website also advises the public to call local law 

enforcement if they see someone operating a UAS in a reckless or 

irresponsible manner.

FAA also educates recreational and commercial small UAS pilots—both 

unilaterally and through coordination with other federal departments and 

agencies as well as industry—regarding current guidelines and 

registration requirements. FAA partnered with three industry groups—the 

Association for Unmanned Vehicle Systems International (AUVSI),32

AMA, and the Small UAV Coalition33—to develop and implement the 

Know Before You Fly Program,34 a campaign to educate prospective 

users about the safe and responsible operation of UAS. In addition, in 

January 2016, FAA released its B4UFLY35 smartphone application that 

helps UAS pilots determine whether any restrictions or requirements are 

in effect at the location where they intend to fly. FAA’s educational efforts 

have also included attending industry conferences and holding its own 

annual UAS symposium, where stakeholders can speak directly to 

regulators and industry representatives.36

FAA has taken further action in response to a 2016 act requiring 

manufacturers of small UAS to make a safety statement available to the 

 32AUVSI represents the views of the unmanned systems and robotics community to 

government officials, regulators, media, and the public.

33The Small UAV Coalition is a partnership of consumer and technology companies to 

support and advocate for a law and policy changes that will embrace and encourage the 

growth of the UAV industry.

34For more information, see http://knowbeforeyoufly.org/. 

35For more information, see http://www.faa.gov/uas/where_to_fly/b4ufly/. 

36The first symposium was held on April 19-20, 2016 in Daytona Beach, Florida. The 

second forum was held March 2017 in Reston, Virginia. The 2018 symposium was held 

March 6-8 in Baltimore, Maryland.

Education Efforts
Page 20 GAO-18-110 Small Unmanned Aircraft Systems

owner that satisfies certain requirements, including recommendations for 

using small UAS in a safe manner.37 This requirement is to take effect 

one year after FAA develops relevant guidance. In the interim, FAA has 

developed a sample safety statement intended to serve as an example 

that small UAS manufacturers may use. The sample statement describes 

some of the regulations, and safety tips consumers need to know when 

operating UAS.38

FAA has also partnered with the Forest Service and federal, state, and 

local wildland fire agencies to educate recreational small UAS pilots about 

not flying near forest-firefighting operations. In 2015, the Department of 

the Interior, the Forest Service, and FAA implemented If You Fly, We 

Can’t, a UAS awareness campaign, as a communication tool to keep 

UAS pilots away from airspace used by aerial-firefighting operations. FAA 

has expressed concern about the effect of the range of state and local 

laws on UAS operations, and how these varying laws might adversely 

affect safety in the NAS. Therefore, in December 2015, FAA published a 

fact sheet intended to help states and localities ensure that any legislation 

or regulation they are considering that affects UAS is consistent with the 

federal statutory and regulatory framework for aviation.

In addition to educating users, in December 2015, FAA began requiring 

recreational small UAS users to register their UAS with FAA.39

(Commercial users were already required to register their UAS.) 

Historically, according to agency officials, FAA did not enforce aircraft 

registration requirements for traditional model aircraft40 but did have a 

registration system in place.41 In 2015, in the interests of public safety and 

 37FAA Extension, Safety, and Security Act of 2016, § 2203.

38The act required that this guidance be published one year after its enactment, which 

occurred in July 2016.

39This requirement was not in effect from May 19, 2017 (when it was invalidated by a 

United States Court of Appeals based on the prohibition in § 336 of the 2012 act against 

FAA promulgating regulations regarding recreational small UAS) until December 12, 2017 

(when it was restored by a newly enacted law). Taylor v. Huerta, 856 F.3d 10889 (D.C. 

Cir. Mar. 14, 2017); National Defense Authorization Act for Fiscal Year 2018, Pub. L. No. 

115-91 § 1092(d), 131 Stat. 1283 (2017).

40While some types of small UAS are relatively new, traditional fixed-wing unmanned 

aircraft have been in development since World War I, and since World War II, the UAS 

market has been a hobbyist market.

41Under 14 C.F.R. pt. 47, all aircraft are required to be registered under a paper-based 

registration system with FAA.

Registration Requirements
Page 21 GAO-18-110 Small Unmanned Aircraft Systems

the safety of the NAS and in light of the rapid proliferation of UAS in the 

NAS, FAA reevaluated its registration process for small UAS and 

determined that its paper-based registration system was overly 

burdensome. Therefore, in December 2015, the agency published a rule 

that provides recreational and commercial small UAS pilots and operators 

a web-based UAS registration process for the registration of recreational 

and commercial small UAS as an alternative to the existing paper-based 

registration system.42 As of October 31, 2017, FAA’s data indicated over

919,700 registrations had been received—about 820,200 recreational 

users and about 99,500 commercial users—which in total represent 

almost three times the approximately 316,000 manned aircraft registered 

with the agency.43 Figure 3 indicates the locations of small UAS 

registrants across the 50 states and District of Columbia.

 42Prior to issuance of the final rule, FAA required all commercial, public, and nonrecreational UAS operators and pilots to register each small UAS aircraft being used for 

business purposes—which will be discussed later. The new rule allowed commercial 

users to register their small UAS using the alternative, web-based aircraft registration 

process as of March 31, 2016. Registration and Marking Requirements for Small 

Unmanned Aircraft, 80 Fed. Reg. 78,594 (Dec. 16, 2015).

43Under the Registration and Marking Requirements Rule, recreational users can include 

one or more UAS in the same registration, while commercial users must register each 

UAS separately. The counts do not include the more than 3,300 registrations of users 

based in U.S. territories.
Page 22 GAO-18-110 Small Unmanned Aircraft Systems

Figure 3: The Federal Aviation Administration’s Registrations of Recreational and 

Commercial Small Unmanned Aircraft Systems (UAS) Users, as of October 31, 2017
Page 23 GAO-18-110 Small Unmanned Aircraft Systems

According to FAA, registration will help make sure that operators know 

the rules and remain accountable to the public for flying their unmanned 

aircraft responsibly. Failure by recreational users to register can result in 

civil penalties up to $27,500 or criminal penalties or fines of up to 

$250,000 and/or imprisonment up to 3 years. FAA noted that registration 

has another benefit in that several times it allowed FAA to send out 

important safety messages to registrants. In our discussions with a variety 

of UAS stakeholders about FAA’s efforts regarding registration, many (15) 

indicated that the new requirement could achieve a positive impact. Some 

agreed with FAA that registration would encourage safe use (11) and 

allow FAA to better reach out to operators and pilots (10). However, some 

(5) believed registration would do little to encourage safe use because, 

for example, the vast majority of events involving unsafe operation of 

small UAS, the UAS is not recovered or the operator or pilot is not 

located. In part to help address these concerns and in response to a legal 

mandate, FAA convened industry stakeholders to provide 

recommendations on the technologies available for remote identification 

and tracking of UAS.44 The stakeholders provided their recommendations 

to FAA in October 2017. FAA is in the preliminary stages of a rulemaking 

on identification and tracking, and expects to solicit public comments for 3 

months beginning in August 2018 to help shape a proposed rule.

In response to the 2012 act, FAA began working on a plan for integrating 

commercial small UAS operations into the NAS safely and efficiently.45 In 

November 2013, FAA issued a road map for integrating UAS into the 

NAS that outlined a path forward for developing a regulatory framework 

for small UAS operations inside the United States, and for expanding 

UAS uses.46 As shown in table 2, FAA began taking incremental steps in 

2014 toward this goal and has completed phases 1 and 2.

 44FAA Extension, Safety, and Security Act of 2016, § 2202.

45FAA Modernization and Reform Act of 2012, § 332.

46FAA, Integration of Civil Unmanned Aircraft Systems (UAS) in the National Airspace 

System (NAS) Roadmap (November 2013).

FAA Has Taken Some 

Incremental Steps toward 

Allowing Limited 

Commercial Small UAS 

Use in the NAS
Page 24 GAO-18-110 Small Unmanned Aircraft Systems

Table 2: The Federal Aviation Administration’s (FAA) Incremental Approach for Developing a Regulatory Framework for Small 

Unmanned Aircraft Systems' (UAS) Operations

Phase UAS operations covered Time frame

1 Allow operations on a case-by-case basis September 2014 (actual)

2 Finalize regulations allowing routine commercial small UAS use August 2016 (actual)

3 Allow routine operations over people Late 2019 (planned)

4 Allow routine beyond line-of-sight operations Late 2020 (planned)

5 Allow operations in areas where manned aircraft regularly fly March 2020 (planned)

6 Allow unmanned cargo and UAS passenger operations Beyond 2020 (planned)

Source: GAO summary of FAA information. | GAO-18-110

FAA has approached developing a regulatory framework for small UAS, 

much in the same incremental way the agency has approached new 

developments with manned aircraft. Fully integrating UAS into the NAS 

would entail FAA’s establishing all necessary rules, policies, and 

procedures to allow UAS and manned aircraft to operate in the same 

airspace. Each incremental step towards full integration involves UAS 

operations of increasing risk and complexity for operating in the NAS, and 

FAA’s fiscal year 2018 UAS implementation plan for integrating UAS into 

the NAS notes that the agency will determine that an acceptable level of 

safety can be maintained before taking each step.

As required by law, in September 2014, FAA began reviewing and 

approving applications for exemption47 of certain commercial UAS 

operations in the NAS on a case-by-case basis.48 This transitional 

process—used prior to the agency’s implementation of its regulations for 

allowing routine commercial small UAS use in the NAS—provided 

commercial small UAS operators a legal entry into the NAS, while 

maintaining the safety of the NAS. Applicants were required to describe 

their proposed use and any mitigation that would minimize risk to other 

aircraft and to persons and property on the ground, and UAS pilots were 

required to hold a traditional FAA pilot’s certificate. As of August 29, 

 47The authorizations involved FAA exempting UAS from the agency’s aircraft 

airworthiness certification requirements. In broad terms, FAA’s aircraft airworthiness 

certification requirements are that aircraft (1) conform to the FAA-approved design for the 

aircraft’s type and (2) are in condition for safe flight.

48FAA Modernization and Reform Act of 2012, § 333. The case-by-case authorizations 

typically involved an operator’s being authorized to conduct a particular type of operation 

during a certain time period, typically lasting 2 years.

Approval of Operations on a 

Case-by-Case Basis
Page 25 GAO-18-110 Small Unmanned Aircraft Systems

2016—when FAA’s small UAS regulations took effect—FAA had granted 

exemptions to over 5,000 commercial small UAS operators.49

In June 2016, FAA issued the first regulations allowing routine 

commercial small UAS operations in the NAS.50 The regulations took 

effect in August 2016, replacing FAA’s transitional process for authorizing 

commercial use. Among other things, the regulations require commercial 

users to fly their UAS at or below 400 feet and within their visual line of 

sight. Instead of the traditional pilot certificate that FAA had required 

under the transitional process, the regulations require commercial small 

UAS pilots to obtain a new type of pilot certificate. While these regulations 

do not apply to recreational operations, FAA concurrently codified a 

prohibition on recreational users from endangering the NAS. Some 

selected requirements of the regulations include:

• UAS must weigh less than 55 pounds, including equipment and cargo.

• A person operating a small UAS must be at least 16 years old, either 

hold a remote pilot certificate with a small UAS rating and pass a 

security background check by the Transportation Security 

Administration, or be under the direct supervision of a person who 

holds a certificate.

• Visual line-of-sight and daylight operations only.

• No operations in certain classes of airspace without air traffic control 

permission.

• Small UAS pilots must yield right of way to other aircraft.

• Maximum altitude of 400 feet above ground level and maximum 

groundspeed of 100 miles per hour.

FAA allows users to request a waiver for most of the operational 

restrictions in its small UAS regulations. To obtain a waiver, users must 

 49FAA was required to certify by October 13, 2016, that the agency’s waiver process 

include small UAS operations associated with critical infrastructure and that involve 

beyond visual line-of-sight and daytime or nighttime operations. FAA Extension, Safety, 

and Security Act of 2016, § 2210. In January 2017, FAA provided the required certification 

to Congress.

50These regulations are referred to as Part 107, and are codified at 14 C.F.R. §§ 107.1-

107.205. The regulations apply to all civil small UAS operations other than operations 

included under the special rule for model aircraft and public aircraft —e.g., aerial 

photography; educational and academic purposes; inspections of antennas, bridges, 

pipelines, and powerlines; and research and development.

Regulations Allowing Routine 

Small UAS Use
Page 26 GAO-18-110 Small Unmanned Aircraft Systems

demonstrate to FAA that they can safely conduct the proposed operation. 

For instance, if a commercial operator wants to conduct small UAS 

operations at night, the operator would have to apply to FAA and 

demonstrate the ability to safely do so. As of May 10, 2018, FAA had 

issued 1,784 waivers, most of which waived the requirement for daylight 

operations (1,598).

Going forward, FAA plans to continue to follow this incremental approach 

of adding to and amending its small UAS regulations to eventually allow 

both small and large UAS full access to the NAS. Thus far, FAA has 

made progress in planning for the phases that allow operations over 

people and expanded operations beyond line of sight, as described 

below.

FAA is developing standards designed to routinely and safely allow small 

UAS operations over people who are not directly involved in the operation 

of the aircraft (the public) in urban areas. In February 2016, FAA 

chartered the Micro Unmanned Aircraft Systems Aviation Rulemaking 

Committee (ARC) to develop recommendations for developing a 

performance-based standard that would allow certain UAS to be operated 

over non-participating people. In recommendations issued in an April 

2016 report, the ARC identified four small UAS categories defined 

primarily by level of risk of injury posed by operations over people. For 

each category, the ARC recommended performance standards and 

operational restrictions to minimize risks. FAA had planned to issue a 

proposed rule on operations over people by the end of 2016 and a final 

rule by the end of 2017. FAA tentatively plans to issue a regulation 

allowing routine operations over people in late 2019. FAA also expects 

the proposed rule to be informed by FAA’s Pathfinder 1 project being 

conducted in partnership with Cable News Network (CNN) to explore safe 

Operations over People
Page 27 GAO-18-110 Small Unmanned Aircraft Systems

methods of small UAS operations in populated areas.51 See figure 4 for 

more information about the Pathfinder 1 project.

Figure 4: Description of the Federal Aviation Administration’s (FAA) Pathfinder 1 Project for Small Unmanned Aircraft 

Systems (UAS) for Operations over People

 51FAA signed a cooperative research and development agreement with Cable News 

Network for conducting the Pathfinder project. A cooperative research and development 

agreement is entered into between one or more federal agencies or laboratories and one 

or more non-federal parties under which the government, through its laboratories, 

provides personnel, services, facilities, equipment, intellectual property, or other resources 

with or without reimbursement (but not funds to non-federal parties), and the non-federal 

parties provide funds, personnel, services, facilities, equipment, intellectual property, or 

other resources toward the conduct of specified research or development efforts that are 

consistent with the mission of the agencies or laboratories; except that such term does not 

include a procurement contract or cooperative agreement as those terms are used in 31 

U.S.C. §§ 6303, 6304, and 6305 nor does such term include other transactions, as that 

term is used in 49 U.S.C. § 106(l)(6). See 15 U.S.C. § 3710a(d)(1).
Page 28 GAO-18-110 Small Unmanned Aircraft Systems

FAA also plans to develop standards designed to routinely and safely 

allow small UAS operations beyond the visual line of sight of the pilot, for 

those operations that are not currently allowed without a waiver.52

According to FAA and some aviation industry stakeholders we 

interviewed, beyond visual line-of-sight operations are critical to enabling 

the commercial potential of small UAS. For instance, many of the 

proposed commercial uses, such as package delivery and infrastructure 

inspection, will require the aircraft to be able to fly safely well beyond the 

visual range of the pilot. Through cooperative research and development 

agreements, FAA is engaged in two additional Pathfinder projects 

intended to inform the agency’s development of standards for expanded 

operations: Pathfinder 2 with PrecisionHawk to test and evaluate 

extended visual line-of-sight operations in rural areas and Pathfinder 3 

with BNSF Railway to test and evaluate beyond visual line-of-sight 

operations in rural or isolated areas. See figure 5 for additional 

information on these projects.

 52As mentioned above, beyond visual line of sight refers to operations that take the UAS 

farther than the pilot’s or any other participating visual observer’s direct vision of the UAS, 

with vision unaided by any device other than corrective lenses. Extended visual line of

sight refers to operations outside the UAS pilot’s direct vision but within an area in which 

the UAS pilot or one or more remote visual observers are able to spot manned aircraft that 

happen to fly into the area. This definition of extended visual line-of-sight is not statutory, 

but instead based on PrecisionHawk’s definition.

Beyond Line-of-Sight 

Operations
Page 29 GAO-18-110 Small Unmanned Aircraft Systems

Figure 5: Descriptions of the Federal Aviation Administration’s (FAA) Pathfinder Projects 2 and 3 for Small Unmanned Aircraft

Systems (UAS) for Beyond Line-of-Sight Operations

Half of the industry stakeholders who discussed the Pathfinder projects 

with us expressed positive views about them. However, some noted that 

although these projects are a good starting point, changes are needed. 

For example, three stakeholders said the projects need to be expanded to 
Page 30 GAO-18-110 Small Unmanned Aircraft Systems

include other companies, while two others were not clear on what is to be 

done with the resulting data. FAA tentatively plans to issue a regulation 

allowing routine beyond visual line-of-sight operations in late 2020.

FAA has taken some steps toward fully integrating UAS into the NAS. For 

example, the agency has developed a plan and taken preliminary steps 

for the next-to-final phase of integrating UAS into the NAS—nonsegregated operations that would enable both larger UAS and small UAS 

to operate in the same airspace as manned aircraft. According to FAA, 

such operations might involve interaction between UAS pilots and air 

traffic controllers in a manner similar to how a manned aircraft conducting 

flight under instrument flight rules does today. Also, the UAS operating in 

this environment might be required to meet FAA’s performance and 

equipage standards for the airspace class or route used.53 FAA’s plan 

calls for the agency to issue a final rule to allow non-segregated 

operations in the second quarter of fiscal year 2020. FAA is also 

developing a detailed implementation plan to reach the final phase of 

integrating UAS into the NAS—the use of UAS for delivering small cargo 

within state boundaries and the use of larger UAS for transporting 

passengers.

 5314 C.F.R. pt. 91 codifies federal aviation regulations for governing the operation of an 

aircraft within the United States including, among other things, equipage requirements and 

performance standards. To operate an aircraft in the different classes of airspace and at 

various altitudes in the NAS, specific equipage and performance standards must be met 

for the aircraft being operated. An example for an equipage requirement for operating an 

aircraft in an airspace class could be the requirement for having a transponder, i.e., 

equipment that would help identify the precise location of the aircraft or to electronically 

transmit identification information. Further, each aircraft is designed to meet certain 

operational and performance standards—e.g., pertaining to takeoff, rate of climb, range of 

flight, rate of descent, and landing—that determine the practical use of the aircraft’s 

capabilities and limitations.

Final Actions to Full Integration
Page 31 GAO-18-110 Small Unmanned Aircraft Systems

FAA has sought to ensure compliance with safety standards related to 

recreational and commercial small UAS operations by taking a variety of 

actions. While FAA is legally prohibited from promulgating regulations for 

recreational small UAS, FAA has the authority to take enforcement action 

against the operator or pilot of any small UAS that endangers the safety 

of the national airspace system or persons and property on the ground. 

FAA officials told us that the agency is following its “compliance 

philosophy” to help ensure users abide by the small UAS regulations.54

Under this philosophy, FAA’s approach involves three types of possible 

actions: (1) compliance actions,55 (2) administrative actions, and (3) legal 

enforcement actions (see table 3). The compliance philosophy also calls 

for FAA to emphasize the use of compliance actions over enforcement 

actions whenever appropriate. According to FAA’s data, from June 7, 

2007 through May 2, 2018 the agency took 420 compliance actions, 49 

administrative actions, and 49 enforcement actions against small UAS 

users; the data do not distinguish between recreational and commercial 

users.

 54Before June 2015, FAA’s regulatory policy focused on legal enforcement action as a first 

step to address regulatory noncompliance. FAA now allows individuals and organizations 

the agency oversees to take steps to address a noncompliance finding and demonstrate 

compliance before initiating an enforcement action, except in certain cases such as an 

unwillingness or inability to comply.

55The term “compliance action” is new for FAA and refers to non-enforcement methods—

such as counseling, on-the-spot corrections, and additional training—for correcting 

unintentional deviations or noncompliance that arise. A compliance action is not 

adjudication, nor does it constitute a finding of violation.

FAA Has Used a Variety of 

Actions to Address 

Noncompliance and 

Unsafe Use of 

Recreational and 

Commercial Small UAS
Page 32 GAO-18-110 Small Unmanned Aircraft Systems

Table 3: Numbers of Actions Taken by the Federal Aviation Administration (FAA) to Address Noncompliant or Unsafe Use of 

Small Unmanned Aircraft Systems, from June 7, 2007 through May 2, 2018

Type of action Description Number of actions taken

Compliance FAA uses on-the-spot correction, counseling, additional training, 

or other cooperative means for correcting unintentional 

deviations or noncompliance that arise from factors such as 

flawed systems and procedures, simple mistakes, lack of 

understanding, or diminished pilot skills

420

• Counseling or other informal action 368

• On-the-spot correction 21

• Additional training 6

• Other 25

Administrative FAA issues warning notices or letters of correction when the 

agency determines that a compliance action would be 

ineffective and when enforcement action is not required or 

warranted.a

49

• Warning notice 40

• Letter of correction 9

Legal enforcement FAA assesses civil penalties or suspension or revocation of 

pilots’ or operators’ certificates in cases of intentional or 

reckless deviations from FAA’s standards or in cases that are 

otherwise unacceptably unsafe, and also in some cases of 

repeated noncompliance or where pilots or operators fail to 

correct noncompliance following an FAA compliance or 

administrative action.

49

• Civil penalty

• Suspension of certificate

• Revocation of certificate

46

1

2

Source: FAA. l GAO-18-110

a

A warning notice advises the noncompliant entity of the facts and circumstances constituting 

noncompliance and requests future compliance. A letter of correction serves the same purposes as a 

warning notice and also memorializes the specific agreement between FAA personnel and the 

regulated entity as to the particular corrective action taken.

FAA officials told us that given its overall responsibilities for aviation 

safety and the lower risk posed by small UAS compared to manned 

aircraft, its resources for actively pursuing unsafe small UAS users are 

limited, and identifying such users is challenging. The 2016 act authorized 

FAA to begin immediately assessing civil penalties of up to $20,000 for 

UAS pilots or operators who knowingly or recklessly interfere with wildfire 

suppression, law enforcement, or other emergency response activities.56

 56FAA Extension, Safety, and Security Act of 2016, § 2205.
Page 33 GAO-18-110 Small Unmanned Aircraft Systems

FAA told us that as of May 2018, FAA had used this authority to assess 

one civil penalty in the amount of $9,700 and to initiate another 

enforcement case that was still open. Additionally, since 2016, the 

Department of Transportation Inspector General (DOTIG) has been 

conducting investigations of serious violations of UAS related 

regulations—e.g., involving injury to persons, property damage, or 

operating near an airport. As of May 2018, the DOTIG had initiated 25 

cases nationwide, with five investigations ongoing; however, no 

indictments or convictions had resulted. According to DOTIG, these 

investigations have largely been initiated as a result of police reports to 

FAA that FAA referred to DOTIG, which has criminal investigative 

authority whereas FAA does not.57

According to FAA and NASA, in order to fully integrate commercial small

UAS in the NAS, a traffic management system that is similar to FAA’s airtraffic-control system for manned aviation may be needed to control 

access and flight operations. In 2013, NASA began developing a concept 

of operations for a UAS Traffic Management System (UTM) that would 

enable routine, diverse small commercial UAS operations that are below 

400 feet and beyond the line of sight, and operated in a manner that 

allows for multiple user interactions. Such operations could include 

delivery of small packages, as proposed by Amazon and Google. UTM is 

not considered to be a single full system for the continental United States 

but, according to NASA officials, will likely be composed of small local 

and regional systems (see fig. 6). According to a 2017 NASA Office of 

Inspector General report, the project received a total of $47.6 million in 

funding in fiscal years 2015 through 2017. NASA officials noted that UTM 

is a step beyond the Pathfinder Program because it allows for multiple or 

diverse user interactions.

 57DOTIG coordinates its investigations with FAA, DOJ, local police, airports, and state and 

local governments.

FAA Is Collaborating with 

NASA to Determine 

Feasibility of a System for 

Managing UAS Traffic
Page 34 GAO-18-110 Small Unmanned Aircraft Systems

Figure 6: Illustration of a Potential Model for the National Aeronautics and Space Administration’s (NASA) Concept of 

Operations for the Unmanned Aircraft System Traffic Management System

NASA is leading the research, development, and testing of the various 

technologies that would comprise the system, and is coordinating with 

FAA and other government agencies as well as over 200 industry and 

academic partners. The work is taking place in four phases, each 

increasing in complexity. See table 4 for the project’s schedule. Finally, 

FAA’s long-term vision includes fully integrated commercially operated 

small UAS operating in the same airspace as manned aircraft and using 

many of the same air-traffic-management systems and procedures. This 

will represent a substantial shift from the approach of requiring UAS to 

operate separately in the NAS. According to NASA officials, the agency 

has held three large events on its progress on UTM and participated in 

many of the national and international conferences with presentation 

panels on UTM.
Page 35 GAO-18-110 Small Unmanned Aircraft Systems

Table 4: The National Aeronautics and Space Administration’s (NASA) Project Schedule for a Traffic Management System for 

Unmanned Aircraft Systems (UAS) 

Phase Completion date Focus area Application

1 August 

2015

Field testing and additional testing at an FAA site. Technologies 

in this activity included “geofencing”—which establishes virtual 

fences around areas or points of interest to keep UAS away—

altitude “rules of the road,” and scheduling of UAS flight 

trajectories.

Agriculture, firefighting, 

and infrastructure 

monitoring

2 February 

2017

Beyond visual line-of sight operations in sparsely populated 

areas. Researchers tested technologies that allow dynamic 

adjustments to availability of airspace and management of 

contingencies, such as the loss of the communications link 

between the small UAS and the pilot’s handset for controlling the 

UAS.

Longer range 

applications

3 February 

2018

Testing technologies that maintain safe spacing between 

cooperative (responsive) and non-cooperative (non-responsive) 

UAS over moderately populated areas.

Public safety, 

limited package 

delivery

4 October 

2019

UAS operations in higher-density urban areas for tasks such as 

news gathering and package delivery and testing technologies 

that could be used to manage large-scale contingencies, such as 

unanticipated severe weather and outages of cell phone and 

global positioning system services that could support the UAS 

traffic management system.

News gathering, 

package delivery, 

and personal use

Source: NASA and the Federal Aviation Administration (FAA). | GAO-18-110

In 2015, FAA and NASA established a research transition team to 

coordinate the UTM initiative. NASA expects to transfer the results of its 

research in the form of airspace integration requirements to FAA, and 

FAA will determine next steps with UTM research. FAA officials told us 

that the agency does not expect to operate such a system but according 

to NASA officials, if FAA chooses not to implement and operate UTM, 

other organizations could do so with commercially developed traffic 

management systems. Furthermore, FAA officials have stated that there 

are policy, regulatory, and infrastructure implications that must be fully 

understood and addressed before a UTM could be implemented, and that 

it is possible that alternatives to, or portions of, the concept could be 

implemented rather than the entire concept. Most of the industry 

stakeholders with whom we discussed UTM spoke positively about it. In 

September 2017, NASA’s Inspector General reported that NASA’s UTM 

project was progressing as planned within allocated cost and schedule 

resources, and that as a result of UAS flight tests in realistic operating 

environments, NASA researchers have made progress in addressing 
Page 36 GAO-18-110 Small Unmanned Aircraft Systems

specific technology challenges related to UTM.58 The Inspector General

for NASA also reported that NASA had collaborated effectively with FAA 

to establish a process for transferring UTM research results from NASA to 

FAA.

Pursuant to law, FAA, in coordination with NASA, is required to develop a 

research plan for UTM by January 11, 2017.59 The agency and NASA 

collaborated to develop such a plan, and FAA officials told us that the 

agency submitted it to Congress in April 2017. FAA, in coordination with 

NASA and the Drone Advisory Committee, is also required to establish a 

2-year pilot program for UTM within 90 days of completing the research 

plan. FAA officials told us the agency is working with NASA and the 

Drone Advisory Committee to prepare for the pilot program, which FAA 

plans to begin in 2018.

In addition to a UTM, some policy and technological tools have been 

identified by federal agencies, aviation industry stakeholders, and others 

as having the potential to mitigate risks associated with unauthorized 

small UAS operations and aid in achieving FAA’s goal of full integration of 

small UAS in the NAS. See appendix I for a listing and descriptions of 

selected technologies that are at various stages of research and 

development. FAA has also coordinated with industry and academic 

stakeholders on efforts intended to inform its decisions for how to manage 

the safety risks associated with small UAS and to support and facilitate 

integrating small UAS into the NAS. See appendix III for descriptions of 

several of these efforts.

 58NASA, Office of Inspector General, NASA’s Research Efforts and Management of 

Unmanned Aircraft Systems, Report No. IG-17-025 (Washington, D.C.: Sept. 18, 2017).

59FAA Extension, Safety, and Security Act of 2016, § 2208.
Page 37 GAO-18-110 Small Unmanned Aircraft Systems

To support FAA’s mission to provide a safe and efficient National 

Airspace System, FAA’s policy on safety risk management60 requires FAA 

to follow a process for managing risk that includes identifying hazards;61

analyzing and assessing associated safety risks;62 and developing and 

monitoring safety risk controls to reduce the risks to an acceptable level. 

From this policy, we identified five key FAA principles for safety risk 

management and 15 specific requirements that support those principles 

(see table 5). We assessed FAA’s risk management practices for 

selected agency efforts related to small UAS against these principles and 

requirements. We selected FAA efforts that involved development of 

regulations for small UAS or issuing waivers or exemptions to those 

regulations or other aviation regulations. The efforts were:

• development of the rule on registration of small UAS; 

• the transitional process for authorizing commercial small UAS use; 

• development of the small UAS regulations; 

• the process for waiving certain requirements in the small UAS 

regulations; 

• the process for approving requests from small UAS pilots for 

authorization to operate in airspace served by air traffic control;

and 

 60The policy applies to all of FAA’s functions when making planned changes to the NAS 

and when potential and previously unidentified hazards and ineffective safety risk controls 

are discovered.

61FAA defines hazard as a condition that could foreseeably cause or contribute to an 

accident.

62FAA defines safety risk as the composite of predicted severity and likelihood of the 

potential effect of a hazard. FAA defines severity as the consequence or impact of a

hazard’s effect or outcome in terms of degree of loss or harm. FAA defines likelihood as 

the estimated probability or frequency, in quantitative or qualitative terms, of a hazard’s 

effect or outcome.

In Selected Efforts 

Related to Small 

UAS, FAA Followed 

Risk Management 

Principles to Varying 

Extents
Page 38 GAO-18-110 Small Unmanned Aircraft Systems

• the two Pathfinder projects.63

We identified FAA’s risk management practices for these efforts by 

reviewing FAA documents that describe the agency’s processes and 

decisions for each effort.64 We then determined whether each principle 

was followed—meaning all three requirements under the principle were 

followed; not followed—meaning all three requirements under the 

principle were not followed; or partially followed—meaning that the 

principle was neither followed nor not followed. Our assessments of the 

extent to which FAA followed the requirements under each principle 

served as the basis of our overall assessments of the extent to which 

FAA followed each principle. Appendix II provides further detail on our 

methodology.

As shown in table 5, of the five key principles of safety risk management, 

we determined that FAA followed two and partially followed three in 

managing risks for the selected agency efforts related to small UAS. More 

specifically, we found that of the 15 requirements under those key 

principles, FAA followed 9 and partially followed 6. The discussion that 

follows provides more detail on our results.

 63We assessed FAA’s risk management practices for the Pathfinders with BNSF Railway 

and PrecisionHawk. However, we did not assess FAA’s risk management process for the 

Pathfinder with CNN because that process mainly involved FAA approving CNN’s 

operations under the agency’s transitional process for authorizing commercial small UAS 

use, and we assessed that process separately.

64These documents included documents that FAA refers to as “Safety Risk Management 

Documents” (standardized documentation on the agency’s risk management steps taken 

for the effort, such as risk assessments and selections of safety risk controls); two rules; 

and authorizations issued under its transitional process and that FAA used as a basis for 

expediting its reviews of subsequent requests for authorization of similar operations.
Page 39 GAO-18-110 Small Unmanned Aircraft Systems

Table 5: GAO’s Assessment of the Extent to Which the Federal Aviation Administration’s (FAA) Management of Safety Risks 

Posed by Small Unmanned Aircraft Systems Followed Key Risk Management Principles

Principles and supporting requirements

Extent 

followed

Define appropriate roles and responsibilities for safety risk management 

Identify teams or individuals responsible for conducting the safety-risk management process 

Team must include representatives from the various FAA organizations that could be affected by safety risk 

management decisions 

Identify managers accepting safety risks 

Describe the aviation system under consideration and identify its hazards 

Describe the aviation system and issue under consideration 

Identify hazards 

Identify existing safety risk controls 

Analyze and assess safety risks 

Identify potential causes and effects associated with each hazard 

Analyze safety risks in terms of severity and likelihood 

Assess the acceptability of safety risks based on their severity and likelihood compared to risk acceptance criteria 

Control safety risks 

Identify safety risk controls considered 

Select controls and provide rationale 

Determine that any remaining safety risks are acceptable based on their severity and likelihood compared to risk 

acceptance criteria 

Monitor hazards and related controls and adjust controls as needed 

Describe how hazards and related controls will be monitored against safety-risk acceptance criteria 

Monitor the effectiveness of safety risk controls 

Modify or add controls as needed 

Legend:  Followed  Partially followed

Source: FAA’s policy on safety risk management and GAO assessment. l GAO-18-110

Define appropriate roles and responsibilities for safety risk 

management: We found that FAA, in the selected efforts related to small 

UAS, followed this principle. In particular, for each effort, the agency:
Page 40 GAO-18-110 Small Unmanned Aircraft Systems

• identified teams or individuals responsible for conducting the safetyrisk management process,

• indicated that the agency included on the teams representatives from 

the various FAA organizations that could be affected by decisions 

based on the analyses, typically FAA’s air traffic organization and 

FAA’s safety office, and

• identified managers accepting safety risks, with name, title, and 

signatures in the primary safety-risk management document.

Describe the aviation system under consideration and identify its 

hazards: We found that FAA followed this principle, as the agency, for 

each selected effort:

• Described the aviation system under consideration. For example, in 

the safety-risk management document for the PrecisionHawk 

Pathfinder project, FAA explained that the aviation system included, 

among other things, the agency’s transitional process for authorizing 

commercial small UAS use.

• Described the issue under consideration. For example, in the safety 

risk management document for the BNSF Railway Pathfinder project, 

FAA explained that the issue under consideration was that FAA was 

seeking to identify areas and conditions where UAS inspections of rail 

lines could occur safely beyond the visual line of sight of the UAS 

pilot.

• Identified hazards. For example, in a safety-risk management 

document related to the transitional authorization process, FAA 

identified the following four hazards: the pilot of a manned aircraft has 

difficulty seeing a small UAS; failure of the communications link 

between a small UAS and its control station; a small UAS flies away 

from its pilot in an uncontrolled manner; and the pilot loses visual 

contact with the small UAS.

• Identified existing safety risk controls. For example, in a safety-risk 

management document related to the transitional authorization 

process, FAA identified several existing controls, including that small 

UAS pilots were required to hold a private pilot certificate and that 

pilots were required to operate their small UAS during the daytime 

and within their visual range.

Analyze and assess safety risks: We found that FAA, in the selected 

efforts related to small UAS, partially followed this principle. While FAA 

followed the requirement of describing potential causes and effects for 

each hazard, it did not consistently analyze safety risks in terms of 
Page 41 GAO-18-110 Small Unmanned Aircraft Systems

severity and likelihood or consistently assess their acceptability by 

comparing them to the agency’s risk acceptance criteria:

• FAA generally described potential causes and effects for each hazard 

identified in documents related to safety risk management on these 

efforts. For example, in several documents, FAA identified the hazard 

that the pilot of a manned aircraft has difficulty seeing a small UAS. 

The potential causes FAA described for this hazard included the small 

UAS’s size, color, lack of lighting, performance characteristics, lack of 

motion relative to the manned aircraft, and airspeed; the potential 

effects FAA described included a collision and a near midair collision 

between the manned aircraft and the small UAS.

FAA did not consistently analyze safety risks in terms of severity and 

likelihood, and did not consistently assess risks by comparing them to the 

agency’s risk acceptance criteria, as required by FAA’s policies. FAA did 

these for two of the selected efforts related to small UAS, however, the 

agency did not for four others.

• For example, in a document related to the transitional authorization 

process, FAA analyzed the risk, in terms of severity and likelihood, 

associated with the hazard of a pilot of a manned aircraft having 

difficulty seeing a small UAS. FAA then determined the acceptability 

of the risk by plotting the risk on FAA’s risk matrix based on the risk’s 

severity and likelihood (see fig. 7).65 FAA’s analysis concluded that 

the hazard could result in a near midair collision between the manned 

aircraft and the small UAS, which is the second-highest level on 

FAA’s five-level severity scale. FAA also estimated the likelihood of 

such a collision as being extremely remote, which is the secondlowest level of FAA’s scale. Based on the combined severity and 

likelihood of this risk and FAA’s criteria for risk acceptance, FAA 

determined that the risk is medium-level, meaning the risk is 

acceptable, although mitigation is recommended.

• Conversely, for four other efforts related to small UAS, FAA did not 

analyze risks in terms of their severity and likelihood or assess their 

acceptability by comparing them to the agency’s risk acceptance 

 65FAA’s risk levels are low, medium, and high. FAA’s criteria for acceptability of risks are 

that low-level risks are acceptable without any mitigation; medium-level risks are 

acceptable, although mitigation is recommended; and high-level risks are unacceptable, 

and the proposed change to the NAS cannot be implemented unless the risk is mitigated 

to medium or low.
Page 42 GAO-18-110 Small Unmanned Aircraft Systems

criteria.66 While FAA’s documents related to those efforts generally 

describe the potential causes and effects associated with hazards—

such as the hazard of the pilot of a manned aircraft failing to see a 

small UAS due to the difficulty of seeing it, and resulting in a collision 

between the manned aircraft and the small UAS—they did not assign 

severity levels, nor did they include estimates of their likelihoods. 

Therefore, while FAA made determinations of whether risks were 

acceptable, its determinations were not based on assessments of 

severity and likelihood levels. FAA officials told us that the agency 

does not always have sufficient data to assess the likelihood of risks. 

However, for some of its other key efforts for which it lacked sufficient 

data on which to base estimates of severity and likelihood, FAA relied 

on expert judgment to make estimates, as allowed under the agency’s 

safety risk management policy. As discussed earlier, FAA’s lack of 

reliable data about the extent of unsafe use of small UAS limits its 

ability to oversee the safe integration of these aircraft into the NAS. 

Absent an assessment of severity and likelihood, FAA could not 

demonstrate that the risks it identified as needing mitigation exceeded 

the agency’s risk acceptance criteria or that the risks it identified as 

acceptable fell below the criteria.

 66The four efforts were the transitional authorization process, development of the small 

UAS regulations, the process for waiving certain requirements in the small UAS 

regulations, and the rule on registration requirements for small UAS.
Page 43 GAO-18-110 Small Unmanned Aircraft Systems

Figure 7: The Federal Aviation Administration’s (FAA) Air Traffic Organization’s 

Criteria for Acceptability of Safety Risks Posed by Unmanned Aircraft Systems 

(UAS)

Notes: FAA defines safety risk as the composite of predicted severity and likelihood of the potential 

effect of a hazard. FAA defines likelihood as the estimated probability or frequency, in quantitative or 

qualitative terms, of a hazard’s effect or outcome. FAA defines severity as the consequence or impact 

of a hazard’s effect or outcome in terms of degree of loss or harm.

a

Minimal severity refers to outcomes in which a UAS causes discomfort to those on the ground.

b

Minor severity refers to outcomes in which a UAS causes non-serious injury to three or fewer people 

on the ground

c

Major severity refers to outcomes in which (1) a UAS causes non-serious injury to more than three 

people on the ground; (2) a UAS crew experiences a reduced ability to cope with adverse operating 

conditions to the extent that there would be a significant reduction in safety margins; or (3) a UAS 

causes a manned aircraft to make an evasive maneuver, but the UAS and the manned aircraft remain 

greater than 500 feet apart.

d

Hazardous severity refers to outcomes in which (1) the UAS crew is incapacitated; (2) a UAS flies 

within 500 feet of a manned aircraft; or (3) a UAS causes injury to persons other than the UAS crew.

e

Catastrophic severity refers to outcomes in which a UAS collides with a manned aircraft or (2) a UAS 

causes a fatality or fatal injury to one or more persons other than the UAS crew.

f

For risks with likelihood of extremely improbable and a severity of catastrophic, the risk level is high

when the undesirable effect could result from certain types of system failures.

Control safety risks: We found that FAA, in selected efforts related to 

small UAS, partially followed this principle:

• FAA’s documents related to its safety risk management for the 

selected efforts generally (1) describe the safety risk controls the 
Page 44 GAO-18-110 Small Unmanned Aircraft Systems

agency considered, (2) identify the controls it selected, and (3) 

describe the agency’s rationale for its selections. For example, FAA’s 

final rule for small UAS operations described several different types of 

certificates that FAA considered requiring for pilots of commercial 

small UAS, including those for airline transport pilots and commercial 

pilots of manned aircraft, as well as a new type of certificate designed 

for pilots of commercial small UAS. The final rule also stated that FAA 

decided to require the new type of certificate because the other types 

would not ensure that commercial small UAS pilots would have all the 

skills necessary to safely operate a small UAS—such as how to 

maintain visual line of sight—and would also impose the burden of 

training in areas of knowledge inapplicable to small UAS operations, 

such as how to conduct maneuvers of a manned aircraft, including 

takeoff and landing. According to FAA, the new category of remote 

pilot certification from Part 107 has many controls built within the 

operational rule to ensure that a new operator is safer than a noncertificated operator.

• FAA’s documents related to its safety risk management for these 

efforts did not consistently identify any safety risks that could remain 

after implementation of controls in terms of severity and likelihood, as 

required by FAA’s policies. For example, to mitigate the risk 

associated with the pilot of a manned aircraft having difficulty seeing a 

small UAS, one safety-risk management document called for 

implementing the following two risk controls, beyond those already in 

place: (1) requiring commercial small UAS pilots to file, 24 hours in 

advance of their operation, a notice with FAA that describes their 

operation so that FAA can disseminate the information to pilots of 

manned aircraft, and (2) requiring commercial small UAS pilots to 

operate their UAS at least 2 nautical miles from heliports, seaports, 

“gliderports,” and certain airports not served by an air traffic control 

tower. The safety-risk management document includes FAA’s 

assessments that after those controls are implemented, the remaining 

risk associated with the pilot of a manned aircraft having difficulty 

seeing a UAS will be related to the potential for a near mid-air collision 

between a small UAS and a manned aircraft, with a severity of level of 

catastrophic (the highest severity level on FAA’s five-level scale) and 

a likelihood level of extremely improbable (the lowest likelihood on 

FAA’s five-level scale).

• In contrast, FAA’s safety-risk management documents for its process 

for waiving certain requirements in the small UAS regulations did not 

discuss remaining risks at all. In other selected efforts, FAA’s 

documents identified remaining risks but did not provide estimates of 

their severity and likelihood. For example, for an authorization that 
Page 45 GAO-18-110 Small Unmanned Aircraft Systems

FAA granted under its transitional process, allowing small UAS to 

operate on closed film sets, FAA identified a remaining risk of injury to 

persons in close proximity to the UAS. FAA determined that the risk 

was acceptable due in part to the limited size, weight, and safety 

features of the UAS, but did not provide estimates of its severity and 

likelihood. Furthermore, FAA’s safety-risk management documents for 

its process for waiving certain requirements in the small UAS 

regulations did not discuss remaining risks at all. Without descriptions 

of any remaining, unmitigated safety risks in terms of their severity 

and likelihood, FAA lacked a sound basis for deciding which safety 

controls to implement.

Monitor hazards and related controls and adjust controls as needed: 

We found that FAA, in the selected efforts related to small UAS, partially 

followed this principle. Specifically, FAA did not consistently describe how 

it would monitor hazards and related controls against the agency’s risk 

acceptance criteria.

• In documents related to several of these efforts, FAA did describe 

how it would perform such monitoring. For example, in a safety-risk 

management document related to the agency’s transitional 

authorization process, FAA said it would annually review data on near 

midair collisions between manned aircraft and commercial small UAS, 

and established an acceptability criterion of no more than three such 

collisions in one year involving a commercial small UAS operating 

under a certain authorization. In contrast, in documents related to 

several of its other risk management efforts, FAA described the data it 

would monitor but did not establish any acceptability criteria. For 

example, FAA requires commercial small UAS pilots to report to FAA 

accidents that meet certain thresholds for injuries or property damage, 

but did not establish any acceptability criteria, such as a maximum 

acceptable accident rate. Because these risk management efforts lack 

monitoring plans tied to FAA’s risk acceptance criteria, FAA does not 

have the basis required by the agency’s policies for making decisions 

about whether to adjust the controls. As a result, these decisions are 

more susceptible to error.

• To monitor the effectiveness of risk controls and determine whether to 

modify or add controls, FAA reviewed data on accidents, incidents, 

and malfunctions; near mid-air collisions; and sightings of small UAS, 

but these data have limitations. Specifically, FAA generally used selfreported data from commercial small UAS operators as well as 

reports initiated by pilots regarding near mid-air collisions. For 

example, after streamlining the process in March 2015 for approving 

small UAS operations at or below 200 feet, FAA monitored data on 
Page 46 GAO-18-110 Small Unmanned Aircraft Systems

near midair collisions between manned aircraft and small UAS. 

Almost a year later, FAA decided to double the maximum altitude of 

allowable operations from 200 feet to 400 feet. FAA based its decision 

in part on its monitoring of near mid-air collisions—which indicated 

that there had not been any such reports involving authorized 

commercial small UAS. According to FAA, it made the change in 

order to more expeditiously meet the needs of many commercial 

operators, following an increase in the number of such operators who 

were requesting waivers from the 200 foot maximum. FAA told us that 

it also monitors data on sightings of small UAS to assess the 

effectiveness of its risk controls in the small UAS regulations. FAA 

also cited the sightings data in its assessment of safety risks from 

small UAS operations in the rule requiring small UAS registration. 

However, these sources of FAA data on potential unsafe uses of 

small UAS have limitations that affect reliability.

• Furthermore, FAA’s data on near mid-air collisions does not include 

reliable information on whether the involved UAS was an authorized 

commercial small UAS, because FAA currently lacks the means to 

identify the operator or pilot in most such events. Therefore, while 

FAA’s data includes 504 reports of near mid-air collisions between a 

UAS and a manned aircraft from January 2013 through April 2018, the 

data do not indicate how many of these events involved authorized 

commercial small UAS. As such, the data are missing key information 

that FAA needs to monitor the effectiveness of the risk controls in 

place under the 200 foot maximum. As discussed earlier, FAA is 

taking steps to improve its data on the safety of UAS operations.

FAA officials told us that, for the selected efforts, the agency did not 

consistently analyze and assess risks or describe remaining risks in terms 

of severity and likelihood or describe how it would monitor hazards and 

related controls against the agency’s risk acceptance criteria because at 

the time, the agency did not believe that its safety-risk management 

policy applied to all of these efforts. However, in our discussions with 

these officials, they acknowledged that the policy does in fact apply. 

However, FAA has not documented this new position or developed a 

method to ensure proper risk analyses are conducted. Federal internal 

control standards state that an agency’s management should design 

control activities, such as policies and procedures, to achieve objectives 

and respond to risks.

Collectively, FAA’s partial use of key risk-management principles in its 

efforts related to small UAS limits its ability to perform effective safety 

oversight in this area. In particular, its inconsistent analyses of safety 
Page 47 GAO-18-110 Small Unmanned Aircraft Systems

risks posed by these systems and methods for determining which safety 

control to implement limits its ability to determine and implement a level of 

controls and oversight appropriate to the risks these systems pose.

According to DHS, it is responsible for responding to airborne threats, in 

concert with other agencies, and for coordinating efforts for protecting the 

nation’s critical infrastructure. FAA has been coordinating with DHS and 

participating in interagency work groups to assess, detect, and mitigate 

security risks posed by small UAS to the NAS and critical infrastructure. 

In December 2015, FAA and DHS began cooperating on broad research 

activities that support the integration of UAS into the NAS with an 

emphasis on enhancing both aviation safety and security. This research 

has focused specifically on UAS detection and identification technologies. 

The detection of potential threats posed by small UAS operations has 

become increasingly important, as there are more reported sightings of 

UAS flying close to aircraft at some of the country’s busiest airports and 

other sensitive areas. FAA has also been coordinating with DHS and 

others on detection technologies to address safety and security risks 

associated with small UAS operations in the proximity of airports. Table 6 

below describes each of these efforts.

FAA and DHS Have 

Taken Some Actions 

and Coordinated with 

Other Agencies to 

Address Security 

Risks Posed by Small 

UAS

FAA Is Coordinating with 

DHS and Other Agencies 

on Assessing Small UAS 

Security Risks
Page 48 GAO-18-110 Small Unmanned Aircraft Systems

Table 6: Federal Efforts to Research Technologies for Detecting Unmanned Aircraft Systems’ (UAS) Operations near U.S. 

Airports

Name of effort Description

UAS Detection 

Initiative

In October 2015, the Federal Aviation Administration (FAA) initiated a cooperative research and 

development agreement with CACI International Inc. to evaluate how the company’s technology can help 

detect UAS in the vicinity of airports. Starting in January 2016, FAA and Department of Homeland 

Security (DHS) evaluated the company’s UAS detection system. In May 2016, FAA expanded this effort, 

called the UAS Detection Initiative, by signing cooperative research and development agreements with 

three additional UAS detection system manufacturers—Gryphon Sensors, Liteye Systems Inc., and 

Sensofusion. In November 2016 FAA evaluated systems from Liteye Systems, Sensofusion, and CACI at 

Denver International Airport and in April 2017 FAA evaluated Gryphon Sensors’ technology at Dallas-Ft. 

Worth Airport. FAA plans to use the data and findings to develop recommendations for standards that will 

guide the selection of UAS detection systems for airports nationwide.

Interagency UAS 

Detection at 

Airports Strategy 

Working Group

In support of FAA’s UAS Detection Initiative (described above) related to the safety and security needs of 

airports threatened by errant or hostile UAS, FAA and DHS are co-leading an Interagency UAS Detection 

at Airports Strategy Working Group that includes several federal departments and agencies, such as the 

Department of Defense (DOD), Federal Bureau of Investigation (FBI), Department of Energy, and 

Department of the Interior.

The Federal Bureau of 

Investigation’s (FBI) 

detection system

FAA has partnered with FBI to evaluate a different UAS detection technology. Specifically, in May 2016, 

FAA and FBI evaluated an existing FBI-developed UAS detection system at John F. Kennedy 

International Airport.

Department of 

Defense (DOD)

test

In September 2016, as part of its annual joint-U.S. military services exercise to demonstrate and test the 

latest countermeasure technologies for defense against UAS—DOD tested an airport detection scenario 

at a DOD facility in support of FAA’s detection research. Small UAS mitigation technologies were 

evaluated, technologies that would be legally prohibited at a civilian airport. FAA provided flight 

scenarios, air traffic controllers, and a mobile control tower for the test.

MITRE 

Challenge

To assist in the federal government’s counter-UAS technology research, MITRE—a research and 

development center funded by federal agencies including FAA, DHS, and DOD—sponsored an award 

competition (for a total of $100,000) to identify technology solutions that are best able to detect and 

defeat UAS under 5 pounds that could pose a threat to manned aircraft, critical infrastructure, and urban 

areas. MITRE held a demonstration event in August 2016 for field evaluations of the eight finalists’ 

counter-UAS technology at the U.S. Marine Corps Base in Quantico, Virginia.

Source: GAO summary of FAA, DHS, and MITRE information. l GAO-18-110

Pursuant to law, FAA—in conjunction with DHS and other relevant federal 

departments and agencies—is required to establish a pilot program for 

mitigating airspace hazards posed by UAS at airports and other critical 

infrastructure.67 The purpose of the pilot is to ensure that technologies 

that are developed, tested, or deployed to mitigate threats posed by 

errant or hostile UAS operations do not adversely affect or interfere with 

safe airport operations, navigation, air traffic services, or the safe and 

efficient operation of the NAS. FAA officials told us that while detecting 

UAS intrusions at airports falls within FAA’s mission and authority, the 

 67FAA Extension, Safety, and Security Act of 2016, § 2206.
Page 49 GAO-18-110 Small Unmanned Aircraft Systems

agency’s mission does not include countering or disabling small UAS that 

may pose a safety or security risk at airports, action that FAA believes is 

a law enforcement function and responsibility. Congress authorized $6 

million to be appropriated from the Airport and Airway Trust Fund for the 

pilot and required that FAA report the results by January 15, 2018.68

According to FAA, the agency’s work through the Interagency UAS 

Detection at Airports Strategy Working Group, described in table 6 above, 

will meet this requirement. In May 2018, FAA told us that a draft of the 

report was being reviewed internally within FAA and the agency could not 

project a date for the final report to Congress.

FAA is also required, by January 11, 2017, to develop a process for 

entities to request that FAA prohibit or restrict the operation of UAS in 

close proximity to critical infrastructure (such as energy production, 

transmission, and distribution facilities and equipment); oil refineries;

chemical facilities; amusement parks; and other locations that warrant 

such restrictions.69 FAA officials told us that rulemaking is needed to fully 

address this requirement, which FAA does not expect to complete until at 

least 2 years after the deadline in the 2016 act. The officials said FAA will 

continue to consider requests for temporary flight restrictions—which 

include restrictions against operations of small UAS—from DOD and 

other federal security or intelligence agencies to address situations 

determined to be detrimental to the interests of national security.

According to DHS, the National Security Council is also leading an 

interagency effort, which includes FAA and other agencies, to assess 

security risks posed by small UAS and other non-traditional aircraft in the 

National Capital Region.70 In a May 2016 risk assessment under that 

effort, DHS identified 1,560 incidents and encounters of small UAS 

nationwide. DHS conducted the assessment in collaboration with DOD, 

U.S. Park Police, DOJ, FAA, and the Washington, D.C., Metropolitan 

 68The Airport and Airway Trust Fund finances nearly all of FAA’s capital investments in the 

airport and airway system, such as construction and safety improvements at airports and 

technological upgrades to the air traffic control system. The trust fund is principally funded 

by a variety of excise taxes paid by users of the NAS.

69FAA Extension, Safety, and Security Act of 2016, § 2209.

70The National Capital Region is a collection of sovereign jurisdictions whose 

communicators and public information officers collaborate to achieve the safety and 

security of the region. Jurisdictions that comprise the region include the District of 

Columbia; Rockville and Montgomery and Prince George’s County, Maryland; and 

Alexandria and Arlington and Fairfax County, Virginia.
Page 50 GAO-18-110 Small Unmanned Aircraft Systems

Police Department. DHS assessed the risks related to various scenarios 

involving either a small UAS or a manned ultralight aircraft. DHS is also 

co-leading another interagency effort with White House Office of Science 

and Technology Policy to identify technologies capable of mitigating 

security risks from UAS.

Agencies may face legal restrictions to detect or mitigate UAS threats. 

DOJ officials told us that while some use of certain detection technologies 

for UAS may generally be permissible under current law (e.g., systems 

that use radar, electro-optical, acoustic, or radio frequency sensors that 

are configured to passively scan a geographic area for the presence of 

UAS), other activities—such as jamming or hijacking the radio signals that 

control a UAS or taking down a UAS by hitting it with a projectile—may be 

restricted under current statutes. Furthermore, according to DOD, some 

of the most promising technologies for detecting and mitigating UAS may 

be construed to be illegal. For example, several provisions in Title 18 

designed to protect the privacy of electronic communications are 

especially problematic and could inhibit the use of detection systems that 

would record, decode, or capture radio frequency signals transmitted by 

UAS.71 Also according to DOD, mitigation systems that would disable, 

damage, or destroy UAS may conflict with a statute criminalizing 

destructive actions with respect to aircraft72 and potential liability under 

current law restricts innovation, evaluation, and operational use of 

counter-UAS technologies. In response to several agencies’ concern 

about such restrictions, in May 2017, DOD proposed to Congress to grant 

federal agencies legal authority to detect UAS to determine whether they 

pose a threat to the agencies’ facilities or operations and to redirect or 

disable those UAS determined to pose such a threat. DOD included the 

proposed authority in one of its legislative proposals for the National 

Defense Authorization Act for Fiscal Year 2018. The enacted version of 

the act did not include the proposed authority.73

 71Such statutes include the Pen Register Statute and the Trap and Trace Statute, the 

Wiretap Act, or the Computer Fraud and Abuse Act 18 U.S.C. §§ 3121–3127; Title III of 

the Omnibus Crime Control and Safe Streets Act of 1968, 18 U.S.C. §§ 2510–2522; 18 

U.S.C. § 1030.

72Aircraft Sabotage Act of 1984, Pub. L. No. 98-473, 98 Stat. 1837 (codified at 18 U.S.C. § 

32).

73See National Defense Authorization Act for Fiscal Year 2018, Pub. L. No. 115-91.

Federal Agencies May 

Face Legal Restrictions 

against Countering 

Potential UAS Security 

Threats
Page 51 GAO-18-110 Small Unmanned Aircraft Systems

As part of the National Defense Authorization Act for Fiscal Year 2017, 

DOD and DOE were granted authority to take actions—including 

detecting, tracking, and using reasonable force—that are necessary to 

mitigate the threat that a UAS poses to the safety or security of a covered 

facility or asset.74 Both agencies are taking initial steps to utilize this 

authority. For instance, according to a DOD official’s written testimony at 

a congressional hearing in March 2017, the Navy and Air Force are 

working to field counter-UAS capabilities that can effectively detect, track, 

and, if necessary, engage small UAS vehicles. The official also stated at 

a congressional hearing in April 2017 that DOD must update its legal 

guidance, policies, and rules of engagement for its services on how to 

respond to a UAS posing a threat. In an interview with DOE officials, they 

emphasized that the mitigation authority is new and the department is 

developing and implementing the policies necessary to carry out this 

authority, in consultation with the Secretary of Transportation. In addition, 

according to DOE officials, there are other laws that must still be 

considered, such as those related to radio frequency signals.

In our discussions with DHS, officials highlighted the lack of any specific 

authority to counter the threat of nefarious use of UAS, but discussed 

broad authorities that could potentially be utilized. However, as stated 

earlier, Title 18 of the U.S. code may potentially limit the exercise of those 

broad authorities. DHS officials indicated that several of its agencies have 

broad authority that could potentially apply to UAS threat mitigation. For 

example, they told us the Transportation Security Administration has 

broad statutory authority to respond to threats to all modes of 

transportation and to ensure the adequacy of security measures at 

airports and other transportation facilities. The United States Coast Guard 

is authorized to protect ports and waterways from terrorism pursuant to 

the Ports and Waterways Safety Act. Finally, the Federal Protective 

Service could use its law enforcement authorities to protect federal 

 74National Defense Authorization Act for Fiscal Year 2017, Pub. L. No. 114-328, §§ 1697, 

3112, 130 Stat. 2000. For DOD, a covered facility or asset means any facility or asset that

is (a) identified by the Secretary of Defense; (b) located in the United States, including 

territories and possessions; and (c) relates to DOD’s nuclear deterrence, missile defense, 

or national security space missions. For DOE, a covered facility or asset means any 

facility or asset that is (a) identified by the Secretary of Energy; (b) located in the United 

States, including territories and possessions; and (c) owned by the United States or 

contracted to the United States to store or use special nuclear material. The National 

Defense Authorization Act for Fiscal Year 2018 expanded the definition of a covered asset 

or facility to include those that relate to several other DOD’s missions including protecting 

the President or the Vice President and special operations activities. National Defense 

Authorization Act for Fiscal Year 2018, Pub. L. No. 115-91 § 1692, 131 Stat. 1283 (2017).
Page 52 GAO-18-110 Small Unmanned Aircraft Systems

facilities from any threats, including those posed by UAS. DHS noted, 

however, that laws related to radio frequency signals may place 

limitations on DHS’s ability to test and operate some of the most 

promising counter-UAS technologies.

Other agencies highlighted their lack of authority to counter UAS threats. 

For example, a DOI official told us that DOI has no authority to mitigate 

threats from small UAS. However, he noted that the agency has some 

authority to act when its regulations are violated, but this varies widely 

from agency to agency. For example, all National Park Service locations 

are closed to the operations of both commercial and recreational UAS; 

the Park Service typically fines violators, although violators are also 

subject to up to a 6-month jail sentence. USDA’s Office of General 

Counsel indicated that USDA has no agency-specific authority to mitigate 

threats from UAS. However, while not specific to USDA enforcement, a 

recent law established that civil penalties can be assessed up to $20,000 

for UAS pilots who interfere with wildfire suppression, law enforcement, or 

other emergency response activities—and according to FAA, it will 

impose these civil penalties.75 According to U.S. Forest Service officials, 

the agency is considering proposing additional prohibitions related to UAS 

use.

 75FAA Extension, Safety, and Security Act of 2016, Pub. L. No. 114-190, §2205, 130 Stat. 

615 (2016).
Page 53 GAO-18-110 Small Unmanned Aircraft Systems

Table 7 summarizes and compares the regulatory frameworks for small 

UAS operations in the United States and our five selected countries 

(Australia, Canada, France, Japan, and the United Kingdom).76

 76As noted in appendix II, our selection was based on the countries that were suggested 

by a leading UAS industry trade group; that were most often mentioned in our stakeholder 

interviews; that were among the leading countries in the development of a framework to 

ensure the safe and secure operation of small UAS in their respective domestic airspace; 

that have established classes or definitions of UAS; and are members of JARUS. We 

reviewed the regulations and policies of each country.

Selected Foreign 

Countries Are 

Addressing Safety 

Risks from Small 

UAS Operations

The Selected Countries All 

Had Regulations in Place 

for Commercial 

Operations to Address 

Safety Issues
Page 54 GAO-18-110 Small Unmanned Aircraft Systems

Table 7: Comparison of Regulatory Frameworks for Small Unmanned Aircraft Systems’ (UAS) Operations in the United States 

and Five Selected Countries

Element United States Australia Canada France Japan

United 

Kingdom

Distinguishes between commercial and 

recreational use √ √ √ √ √

Regulates recreational small UASa

√ √ √

Regulates commercial small UAS √ √ √ √ √ √

Enforces compliance with laws and regulations √ √ √ √ √ √

Requires authorization to use particular 

airspace √ √ √ √ √ √

Divides small UAS into weight classifications √ √ √ √ √

Requires pilot training or certification √ √ √ √ √

Allows beyond visual line-of-sight operationsb

√ √ √ √ √ √

Restricts altitude √ √ √ √ √ √

Restricts airport proximity √ √ √ √ √ √

Requires small UAS registration √ √ √

Source: GAO analysis of UAS regulations in foreign countries. | GAO-18-110

Note: These are very general comparisons based on each country’s regulations for both small 

commercial and recreational UAS operations. Therefore, a country may be checked as having a 

regulatory requirement even though a specific regulatory requirement does not apply to both 

commercial and recreational operations.

a

In the United States, FAA regulates recreational small UAS by prohibiting recreational small UAS 

from endangering the NAS. However, the FAA Modernization and Reform Act of 2012 prohibits FAA 

from promulgating any regulation regarding a recreational small UAS.

b

All allow beyond line-of-sight operations with conditions, such as in a very limited capacity on a caseby-case basis in segregated airspace.

In addition to the regulations of the five selected countries for integrating 

UAS into their respective airspace, officials from these countries reported 

to us the following actions:

• Two of our five selected countries, like the United States, have 

chosen to rely on community-based organizations—many of whom 

represented the early UAS pilots before the rapid growth of small UAS 

manufacturing and sales—for assistance in providing guidelines and 

education for recreational small UAS pilots.

• All five noted that they coordinate and collaborate with other 

government agencies, and four indicated that they do so with industry.
Page 55 GAO-18-110 Small Unmanned Aircraft Systems

• All five reported collecting data on either encounters with UAS or on 

accidents and incidents involving UAS.77

• Officials from three of our selected countries told us that they were 

using new and reallocated internal resources to meet the new 

challenge of overseeing the emerging small UAS industry.

Table 8 summarizes and compares the regulatory frameworks for small 

UAS operations in the United States and our five additional selected 

countries (China, Germany, Israel, Poland, and South Africa).78

 77For example, the U.K.’s CAA, which also collects UAS sightings reports, uses a board of 

aviation experts to review and vet the reports. The vetting process includes an 

assessment panel of 14 experienced current or former pilots and air traffic controllers who, 

on a monthly basis, review reports of near-misses between aircraft, including reports 

involving small UAS. The panel assesses the information to determine what factors 

caused the incident and the risk of collision on a five-level scale: (1) serious; (2) safety 

compromised; (3) no risk; (4) insufficient information; or (5) normal safety standards 

pertained.

78See Law Library of Congress, Regulation of Drones, April 2016. We reviewed the study 

to summarize these countries’ statutes, regulations, policies, and other efforts regarding 

small UAS safety. We did not independently verify this information with any of the CAAs or 

governments.
Page 56 GAO-18-110 Small Unmanned Aircraft Systems

Table 8: Comparison of Regulatory Frameworks for Small Unmanned Aircraft Systems’ (UAS) Operations in China, Germany, 

Israel, Poland, and South Africa

Element

United 

States China Germany Israel Poland

South 

Africa

Distinguishes between commercial and 

recreational use √ √ √ √

Regulates recreational small UAS √ √ √ √

Regulates commercial small UAS √ √ √ √ √ √

Enforces compliance with laws and regulations √ √ √ √ √ √

Requires authorization to use particular airspace √ √ √ √ √ √

Divides small UAS into weight classifications √ √ √

Requires pilot training or certification √ √ √ √

Allows beyond visual line-of-sight operationsa

√ √ √ √ √

Restricts altitude √ √ √ √

Restricts airport proximity √ √ √ √ √ √

Requires small UAS registration √ √ √

Source: GAO presentation of Law Library of Congress analysis. | GAO-18-110

Note: These are very general comparisons based on each country’s regulations for both small 

commercial and recreational UAS operations. Therefore, a country may be checked as having a 

regulatory requirement even though a specific regulatory requirement does not apply to both 

commercial and recreational operations.

a

All allow beyond line-of-sight operations with conditions, such as in a very limited capacity on a caseby-case basis in segregated airspace.

See appendix IV for additional information on the selected countries’ 

actions to address the safety risks from small UAS operations.
Page 57 GAO-18-110 Small Unmanned Aircraft Systems

Beginning in 2007, through the ICAO’s UAS Study Group and with FAA’s 

participation, ICAO has been involved with establishing guidance on the 

fundamental international regulatory framework needed to support routine 

operation of UAS throughout the world. In 2011, ICAO issued a 

publication aimed at providing a first step in developing such a framework 

for UAS through standards, recommended practices, and guidance 

material.79 In January 2015, ICAO published its Manual on Remotely 

Piloted Aircraft Systems to provide guidance to the entire UAS 

community—including regulators, manufacturers, operators, pilots, and 

air-navigation service providers—on technical and operational issues 

related to the integration of UAS in airspace used by manned aircraft and 

at airports. In December 2016, ICAO added to its website a UAS toolkit 

designed to assist states with development of UAS operational guidance, 

regulations, and enabling operations in a safe manner; and to help UAS 

operators and pilots operate their UAS safely and responsibly. ICAO has 

also hosted social media events to encourage the use of the toolkit as 

well as UAS-related symposiums and workshops.

Another global effort aimed at international harmonization of UAS 

standards is led by JARUS. JARUS’s key aim is to recommend a single 

set of technical, safety and operational requirements for the certification 

and safe integration of UAS.80 To date, JARUS has published nine 

documents related to a range of UAS topics that provide 

recommendations and guidance materials that countries’ aviation 

authorities can use in developing their own rules and regulations—e.g., 

on specifications for unmanned rotorcraft and aircraft and uniform 

personnel licensing and competencies in UAS operation—and has five 

more documents in development.

79ICAO, Unmanned Aircraft Systems, Circular 328 (Montreal, Quebec, Canada: 2011). It 

is in this publication that ICAO shifted from use of the term “UAS” to “remotely piloted 

aircraft system.” The shift was made to better reflect that UAS are piloted.

80JARUS has implemented seven working groups that focus on (1) a concept of 

operations for an appropriate UAS regulatory framework; (2) operations requirements, 

including requirements for access to airspace; (3) requirements for the oversight of 

organizations in such activities as operations and UAS pilot training; (4) establishing UAS 

airworthiness and certification provisions or specifications; (5) designing appropriate 

performance provisions and functions for UAS detect and avoid systems; (6) establishing 

performance provisions for communications systems; and (7) designing UAS 

airworthiness, system safety objectives, and guidance material.

International 

Organizations and the 

European Union Are Also 

Addressing Small UAS 

Safety
Page 58 GAO-18-110 Small Unmanned Aircraft Systems

Currently, the European Aviation Safety Agency (EASA) has no power to 

regulate the use of civilian UAS that weigh 330 pounds or less. This is left 

to the member states, and, according to an EASA official, each of the 28 

members has its own national system for regulating UAS. However, the 

European aviation community agreed on principles for UAS use in a 

March 2015 declaration.81 The declaration included the following key 

guiding principles to be taken under consideration in the future regulation 

of UAS:

• The European Union must deal with UAS as a new type of aircraft and

any safety rules imposed must be proportional to the risk of each

operation.

• The European Union must establish safety rules, technology

requirements, and standards for the integration of UAS into civil

aviation.

A legislative process is underway aimed at shifting responsibility for 

developing a regulatory framework for operations of UAS weighing 330 

pounds or less from the European Union’s member states to EASA. 

Under this framework, EASA would develop the rules and regulations for 

UAS that would be applied by member states, but the oversight of UAS 

operations would be conducted by each member state’s CAA. In August 

2016, EASA published proposed regulations to give member states an 

idea of what to expect should EASA receive this expanded UAS 

authority.82 In December 2017, the member states endorsed an 

agreement to the framework and, according to the European Council, the 

framework is expected to be formally approved in spring 2018.

FAA’s actions to expand the safe use of small UAS in the national 

airspace system have helped enable an increase in the number of 

commercial and recreational uses. As FAA proceeds with its plans to 

achieve full integration of small UAS into the NAS, it will be important for 

FAA to ensure that the safety risks from increased and expanded uses 

are addressed, while enabling development of this technology’s 

81Riga Declaration on Remotely Piloted Aircraft (Drones), Framing the Future of Aviation, 

(Mar. 6, 2015). 

82European Aviation Safety Agency, “‘Prototype’ Commission Regulation on Unmanned 

Aircraft Operations,” August 22, 2016. The EASA official also noted that should EASA not 

receive authority to regulate UAS less than 330 pounds, the proposed regulations would 

serve as a guide for member states developing their own regulations.

Conclusions
Page 59 GAO-18-110 Small Unmanned Aircraft Systems

commercial potential. However, FAA’s ability to perform effective safety 

oversight is limited by FAA’s lack of reliable data on unsafe use of small 

UAS and deficiencies in FAA’s risk management approach. Specifically, 

FAA’s ability to determine and implement a level of controls and oversight 

appropriate to the risks these systems pose is hindered by FAA’s lack of 

reliable data on the safety of these systems in operation and by FAA’s 

inconsistent application of safety risk management principles and 

requirements in the agency’s policies related to analyzing, addressing, 

and monitoring safety risks. FAA is taking steps to improve its data on 

unsafe use of UAS, including evaluating technologies for detecting UAS. 

Improved risk-management practices would help FAA determine whether 

additional actions are needed to ensure the safety of the NAS and would 

provide FAA and other decision makers with confidence that FAA was 

focusing on the most critical safety risks posed by small UAS.

We are making the following recommendation to FAA:

• The Administrator of FAA should establish a mechanism, such as an

internal review procedure, to ensure that FAA’s management of safety

risks posed by small UAS operations in the NAS follows all applicable

principles and requirements in FAA’s policies.

Recommendation for 

Executive Action 
Page 60 GAO-18-110 Small Unmanned Aircraft Systems

We provided a draft of this report to the departments of Agriculture, 

Defense, Energy, Homeland Security, the Interior, Justice, and 

Transportation (FAA), and the National Aeronautics and Space 

Administration for review and comment. In its official comments, 

reproduced in appendix V, FAA agreed with our recommendation and 

provided technical comments, which we incorporated as appropriate. The 

departments of Defense, Homeland Security, and Justice also provided 

technical comments, which we incorporated as appropriate. The 

departments of Agriculture, Energy, and the Interior, and the National 

Aeronautics and Space Administration had no comments.

We are sending copies of this report to the appropriate congressional 

committees, the Secretary of Transportation, the FAA Administrator, and 

other interested parties. In addition, the report is available at no charge on 

the GAO website at http://www.gao.gov.

If you or your staff have any questions about this report, please contact 

me at (202) 512-2834 or by e-mail at KrauseH@gao.gov. Contact points 

for our Offices of Congressional Relations and Public Affairs may be 

found on the last page of this report. GAO staff who made major 

contributions to this report are listed in appendix VI.

Heather Krause

Director, Physical Infrastructure Issues

Agency Comments
Page 61 GAO-18-110 Small Unmanned Aircraft Systems

List of Requesters

The Honorable John Thune

Chairman

The Honorable Bill Nelson

Ranking Member

Committee on Commerce, Science, and Transportation

United States Senate

The Honorable Bill Shuster

Chairman

The Honorable Peter DeFazio

Ranking Member

Committee on Transportation and Infrastructure

House of Representatives

The Honorable Frank A. LoBiondo

Chairman

The Honorable Rick Larsen

Ranking Member

Subcommittee on Aviation

Committee on Transportation and Infrastructure

House of Representatives
Appendix I: Policy and Technology Tools 

Identified as Helpful for Addressing Risks 

Posed by Small Unmanned Aircraft Systems

Page 62 GAO-18-110 Small Unmanned Aircraft Systems

Based on literature we reviewed and interviews we conducted with 

selected federal agencies, aviation industry stakeholders, and others, 

some policies and technologies have been identified as having the 

potential for addressing safety and security risks associated with the use 

of small unmanned aircraft systems (UAS). Table 9 below describes 

these policies and technologies as well as the Federal Aviation 

Administration’s (FAA) status in implementing selected policies and 

technologies. The literature we reviewed included publicly available 

information and documentation from federal agencies—Bureau of 

Reclamation within Department of the Interior, Department of Defense, 

Department of Energy, Department of Homeland Security, FAA, and the 

National Aeronautics and Space Administration—selected aviation 

industry stakeholders and others with expertise on this topic. We also 

conducted interviews with aviation industry stakeholders and officials from 

FAA and the other federal agencies from the obtained documentation. We 

selected these federal and industry stakeholders based on our prior work, 

literature review, and interviews. In consultation with one of our 

technology experts, we reviewed the information we obtained from the 

listed sources that identified policy and technology tools that could 

mitigate the risks associated with unauthorized small UAS operations. We 

did not independently review or assess the information we obtained 

related to these policies and technologies. We also did not attempt to 

determine the appropriateness or potential impact. For further details on 

our methodology, see appendix II.

Appendix I: Policy and Technology Tools 

Identified as Helpful for Addressing Risks 

Posed by Small Unmanned Aircraft Systems
Appendix I: Policy and Technology Tools 

Identified as Helpful for Addressing Risks 

Posed by Small Unmanned Aircraft Systems

Page 63 GAO-18-110 Small Unmanned Aircraft Systems

Table 9: Selected Policy and Technology Tools That Have Been Identified as Potentially Helping to Address Risks Posed by 

Small Unmanned Aircraft Systems (UAS) in the National Airspace System (NAS)

Tool Description

Airspace 

designation

Would limit small UAS flights to designated airspace, thereby separating UAS flights from most 

manned aircraft flights.

FAA currently requires those operating small UAS under the agency’s small UAS regulations to fly 

below 400 feet and remain clear of airspace in which FAA provides air-traffic control service unless 

a waiver or special authorization is obtained.

Flight 

preparation

Would require the pilot of the small UAS to take steps prior to flight such as inspecting the UAS to 

ensure it is in condition for safe flight; becoming familiar with the area of operation including local 

weather conditions, local airspace and any flight restrictions, the location of persons and property 

on the ground, and any other ground hazards; or the filing of a flight plan.

FAA currently requires those operating small UAS under the agency’s small UAS regulations to 

conduct a pre-flight check to ensure the UAS is in condition for safe operation.

Pilot 

certification

Would require the pilot of the small UAS to take a knowledge-based or skills-based test prior to 

being allowed to operate the aircraft.

FAA currently requires only pilots of commercial small UAS to pass a knowledge-based test. 

Individuals who wish to be certified to pilot small UAS and who have a traditional pilot’s certificate 

may take FAA’s online training course and apply for a small UAS rating.

Operator 

certification

Would require prospective commercial operators—i.e., the companies responsible for the

operation of the small UAS—to apply for permission or certification to operate. Applicants could be 

required to describe how their proposed use would minimize risk to other aircraft and to persons 

and property on the ground.

FAA does not require commercial operators to apply for permission or certification to operate.

User education 

or training

Would require recreational small UAS operators (individuals) to be provided with information in 

some form —for example, online, in UAS packages at purchase, or in web applications. FAA could 

also provide or require training on knowledge and skills required to operate small UAS, such as 

small UAS operating principles and rules and airspace rules and procedures.

Although FAA cannot require such training to educate recreational small UAS operators,

a FAA has

implemented, in collaboration with the industry, the Know Before You Fly Program and created the 

Before You Fly mobile application. FAA staff also attends industry meetings and FAA holds its own 

forums to educate and train the industry regarding UAS operations.

Permanent and 

temporary flight 

restriction areas

Would require certain areas or sites to be designated as “No Drone Zones” either temporarily (e.g., 

for a major sporting event) or permanently to protect national historic and other sites and the 

people who use them from danger that could be caused by UAS.

FAA has designated “No Drone Zones” in the United States. For example, the nation’s capital is 

governed by a Special Flight Rules Area within a 30-mile radius of Ronald Reagan Washington 

National Airport, which restricts all flights in the greater Washington, D.C., area. The Special Flight 

Rules Area is divided into a 15-mile radius inner ring and a 30-mile radius outer ring. Flying a UAS 

within the 15-mile radius inner ring is prohibited without specific FAA authorization. Flying a UAS 

between 15 and 30 miles from Washington, D.C., is allowed under certain operating conditions.

UAS certification Would require small UAS, prior to their use, to be certified by FAA to operate within the NAS. 

Certification involves FAA approval of the design, manufacturing, and operations of the aircraft. 

UAS certification could be accomplished via a certificate of conformity. This document would certify 

that the vendor’s product met all certification requirements designed to assure operational safety. 

Currently, all manned aircraft must be certified by FAA to operate within the NAS.

FAA currently does not require certification of UAS but says that it may require such certification in 

the future depending on the type of UAS and the type of operation.
Appendix I: Policy and Technology Tools 

Identified as Helpful for Addressing Risks 

Posed by Small Unmanned Aircraft Systems

Page 64 GAO-18-110 Small Unmanned Aircraft Systems

Tool Description

UAS registration 

and markings

Would require that pilots who are operating small UAS or the UAS itself, or both, be registered with 

FAA as a means to interact directly with them on rules for operating UAS and to provide some 

operator accountability should an accident or violation of regulations occur.

FAA currently requires commercial and recreational small UAS operators to register their UAS with 

FAA. In December 2015, FAA required all small UAS users to register with FAA through a new 

online registration system or through the traditional paper-based system. As part of the registration 

process, users are required to mark their UAS with their registration number.

Sense and 

avoid system

Would provide small UAS with the capability to avoid collisions with other manned and unmanned 

aircraft operating in the NAS. These technologies use instruments on the small UAS that sense 

other aircraft and avoid coming within an unsafe distance of those aircraft. Sensing of other aircraft 

is typically accomplished by receiving a signal from those aircraft. Some technologies sense and 

avoid other obstacles, such as buildings and infrastructure.

FAA does not require this technology for small UAS. However, FAA is working with industry 

partners to develop standards for sense-and-avoid systems to meet FAA’s requirements for being 

used in the NAS.

Command and 

control link

Would provide small UAS with the capability to be operated beyond the visual line of sight of a 

pilot. These technologies use radio spectrum for communications links between the small UAS and 

its control station. These links can be broken by interference from other signals or hacking, causing 

potentially dangerous situations. According to FAA, the reliability of command and control links 

needs to improve before the agency will allow more routine operations of small UAS beyond the 

visual line of sight of the pilot.

FAA requires this technology for small UAS. Command and control link technologies are being 

researched and developed in several countries, including the United States.

Geofencing Would provide the capability to establish or define geographic perimeters separating areas where 

small UAS operations are permissible and those where they are not. These technologies use 

software that is installed on the UAS to compare the UAS’s position with the location of the 

geographic perimeter and determine whether it is in a location where flight operations are 

permitted.

FAA does not require this technology for small UAS. However, research and development efforts 

are under way for this technology, and at least three major small UAS manufacturers are providing 

geofencing functionality with their products.

Radio frequency 

detection

Would provide a method to detect small UAS by the radio signals emitted by most commercially 

available UAS.

Several commercial off-the-shelf products exist for this technology, and research and development 

efforts are under way for this technology. However, these technologies have not yet been deployed 

by FAA or other federal agencies in part because of technical, legal, or operational issues related 

to their use.

Electro-optical 

detection

Would provide a method to detect small UAS by the visible light emitted or reflected by an object.

Several commercial off-the-shelf products exist for this technology, and research and development 

efforts are under way for this technology. However, these technologies have not yet been deployed 

by FAA or other federal agencies in part because of technical, legal, or operational issues related 

to their use.

Infrared 

detection

Would provide a method to detect small UAS by the heat that is emitted by UAS.

Several commercial off-the-shelf products exist for this technology. Research and development 

efforts are under way for this technology. However, these technologies have not yet been deployed 

by FAA or other federal agencies in part because of technical, legal, or operational issues related 

to their use.
Appendix I: Policy and Technology Tools 

Identified as Helpful for Addressing Risks 

Posed by Small Unmanned Aircraft Systems

Page 65 GAO-18-110 Small Unmanned Aircraft Systems

Tool Description

Acoustic 

detection

Would provide a method to detect small UAS by the sounds that are generated by a UAS.

Several commercial off-the-shelf products exist for this technology. Research and development 

efforts are under way for this technology. However, these technologies have not yet been deployed 

by FAA or other federal agencies in part because of technical, legal, or operational issues related 

to their use.

Radar 

detection

Would provide a method to detect small UAS in which radio waves from a transmitter reflect off the 

object and return to a receiver, giving information about the object’s location and speed, and would 

be similar to radars used to detect aircraft in the NAS.

Several commercial off-the-shelf products exist for this technology. Research and development 

efforts are underway for this technology. However, these technologies have not yet been deployed 

by FAA or other federal agencies in part because of technical, legal, or operational issues related 

to their use.

Disabling 

technologies

Would provide the capability to disable small UAS. Once a small UAS is detected, disabling 

technologies could use either physical or electronic communications means to either trap it, 

destroy it, or to force the small UAS to land.

There are several technologies with disabling capability available and in development. However, 

these technologies have not yet been deployed by FAA or other federal agencies in part because 

of technical, legal, or operational issues related to their use.

Source: GAO review of literature and interviews with selected stakeholders. l GAO-18-110

a

The FAA Modernization and Reform Act of 2012 prohibited FAA from promulgating any new 

regulations for small UAS being operated exclusively as model aircraft (which this report refers to as 

“recreational small UAS”), as defined by the law. The law defined model aircraft as unmanned aircraft 

that are (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. The operation of the 

aircraft must also meet the following conditions: (1) the aircraft is flown strictly for hobby or 

recreational use; (2) the aircraft is operated in accordance with a community-based set of safety 

guidelines and within the programming of a nationwide community-based organization; (3) the aircraft 

is 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) the aircraft is 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, the operator of the aircraft provides 

the airport operator and the airport air traffic control tower with prior notice of the operation. FAA 

Modernization and Reform Act of 2012, §§ 336(c), 336(a)(1)-(5).
Appendix II: Objectives, Scope, and 

Methodology

Page 66 GAO-18-110 Small Unmanned Aircraft Systems

This report focuses on the potential safety and security risks posed by 

small unmanned aircraft systems (UAS) operating in the national airspace 

system (NAS) and potential mitigations for those risks. Specifically, this 

report examines: (1) what information is available to the Federal Aviation 

Administration (FAA) about the extent of unsafe small UAS use in the 

NAS, (2) what steps FAA has taken to safely integrate small UAS into the 

NAS, (3) the extent to which FAA’s management of safety risks posed by 

small UAS has followed key principles of risk management; (4) what 

steps selected federal agencies have taken to address security risks 

posed by small UAS operations in the NAS, and (5) what selected foreign 

countries have done to address safety risks associated with the operation 

of small UAS. In addition, this report includes descriptions of selected 

policies and technologies that have been identified as potentially helping 

to address the risks posed by small UAS in the NAS in appendix I.

We reviewed and synthesized available literature and documents related 

to the topic areas, including relevant laws, FAA regulations, government 

and industry reports on efforts to address safety and security risks, and 

related FAA policy, guidance, plans, and safety-risk management 

documents. We also reviewed relevant statutes and regulations. In 

addition, we interviewed FAA officials and conducted semi-structured 

interviews with a broad variety of aviation industry stakeholders, including 

aviation industry groups, aviation companies, aviation experts, law firms, 

and academic institutions. See table 10 for a list of the aviation industry 

stakeholders we interviewed. We judgmentally selected these 46 

stakeholders based on our prior work, literature review, and interviews 

with FAA, other agencies, and aviation industry stakeholders, to include 

those with expertise or experience related to small UAS safety or security 

issues related to integration of small UAS in the national airspace. We 

primarily used a semi-structured interview format with open-ended 

questions to obtain aviation stakeholder perspectives on safety issues 

posed by small UAS operations. The information we obtained from our 

interviews cannot be generalized for aviation industry stakeholders, but 

offers insight into understanding the issues examined in this report.

Appendix II: Objectives, Scope, and 

Methodology
Appendix II: Objectives, Scope, and 

Methodology

Page 67 GAO-18-110 Small Unmanned Aircraft Systems

Table 10: List of Aviation Industry Stakeholders That GAO Interviewed

Category Interviewee

Aviation and other industry groups Airlines for America (A4A)

American Association of Airport Executives (AAAE)

Associated Aerial Firefighters (AAF)

Airports Council International-North America (ACI-NA)

Aerospace Industries Association (AIA)

Association of Air Medical Services (AAMS)

American Helicopter Services & Aerial Firefighting Association (AHSAFA)

Airborne Law Enforcement Association (ALEA)

Academy of Model Aeronautics (AMA)

Aircraft Owners and Pilots Association (AOPA)

Association for Unmanned Vehicles Systems International (AUVSI)

General Aviation Manufacturers Association (GAMA)

Helicopter Association International (HAI)

International Association of Chiefs of Police (IACP)

National Agricultural Aviation Association (NAAA)

National Association of Mutual Insurance Companies (NAMIC)

National Association of State Aviation Officials (NASAO)

Remote Control Aerial Platform Association (RCAPA)

Small UAV Coalition

Companies Amazon Prime Air

The Boeing Company

CACI International

DJI

DroneShield

GE Aviation

Google X

Gryphon Sensors

Honeywell

Liteye

Lockheed Martin Corporation

Robinson Helicopter

Transport Risk Management

Employee organizations Air Line Pilots Association (ALPA)

National Air Traffic Controllers Association (NATCA)

Experts Loretta Alkalay, Vaughn College of Aeronautics
Appendix II: Objectives, Scope, and 

Methodology

Page 68 GAO-18-110 Small Unmanned Aircraft Systems

Category Interviewee

John Goglia, independent consultant; formerly Board Member of the National 

Transportation Safety Board

John Hansman, Massachusetts Institute of Technology

Nathan Schuett, PreNav

Jim Williams, Dentons; formerly head of FAA’s UAS Integration Office

Law Firms Hogan Lovells

Riley Wein

Universities Embry Riddle Aeronautical University (ERAU)

University of North Dakota (UND)

Virginia Tech

Others MITRE

Radio Technical Commission for Aeronautics (RTCA)

Source: GAO. | GAO-18-110

To examine what information is available to FAA about the extent of 

unsafe small UAS use in the NAS, we obtained and analyzed recent FAA 

data on (1) reports by pilots of manned aircraft, air traffic controllers, and 

others of UAS sightings from February 2014 through April 2018; (2) 

reports by pilots of manned aircraft of near mid-air collisions between 

UAS and manned aircraft from January 2013 through April 2018; (3) 

accidents, incidents, and malfunctions required to be reported by certain 

commercial small UAS operators to FAA from March 2015 through 

August 2017;1 and (4) accidents required to be reported by commercial 

small UAS pilots operating under FAA’s regulations from August 29, 

2016, to May 1, 2018.

2 We reviewed documentation about these data and 

the systems that produced them and interviewed knowledgeable FAA 

officials on how the data are collected, maintained, and verified, as well 

as on limitations related to the reliability of the data, and we found the 

data to be sufficiently reliable for our reporting purposes.

 1

A commercial small UAS operator is a company responsible for the operation of a small 

UAS. In September 2014, FAA began reviewing and approving applications to allow 

certain UAS operations in the NAS prior to the agency’s implementation of its regulations 

for allowing routine small UAS use in the NAS—as required under section 333 of the FAA 

Modernization and Reform Act of 2012 (2012 act). FAA requires such operators to submit 

reports of accidents, incidents, and malfunctions to FAA. FAA was able to provide us data 

covering reporting for March 2015 through August 2017.

2

FAA’s regulations, which took effect on August 29, 2016, require commercial small UAS 

pilots to report any operation of a small UAS involving serious injury to any person or loss 

of consciousness, or certain cases of damage to property.
Appendix II: Objectives, Scope, and 

Methodology

Page 69 GAO-18-110 Small Unmanned Aircraft Systems

In addition, we used information obtained during our interviews with 

knowledgeable FAA officials and relevant studies of FAA’s data from the 

Academy of Model Aeronautics (AMA) 3 and the Center for the Study of 

the Drone at Bard College to determine the extent to which FAA’s data 

may inform the extent of potentially unsafe use in the NAS. We assessed 

the extent to which FAA’s data meet federal internal control standards 

related to using quality information to achieve objectives.4 Some of our 

selected aviation industry stakeholders we interviewed shared their 

perspectives on the reliability of FAA’s data on UAS sightings. We 

obtained data from the National Aeronautics and Space Administration’s 

(NASA) Aviation Safety Reporting System—which NASA maintains on 

behalf of FAA—on reports of potentially unsafe use of UAS from January 

2005 through August 2016. We reviewed documentation about these data 

and the system that produced them, including how the data are collected, 

maintained, and verified, and we found the data to be sufficiently reliable 

for our reporting purposes. We also obtained information other selected 

federal agencies collected on UAS sightings related to their missions and 

assets, specifically from the Department of Homeland Security (DHS), the 

Department of Defense (DOD), Department of Energy (DOE), the Bureau 

of Prisons within the Department of Justice (DOJ), the U.S. Park Police 

within the Department of the Interior (DOI), and the U.S. Forest Service 

within the U.S. Department of Agriculture (USDA). We selected these 

agencies based on our discussions with DHS and on literature indicating 

that UAS incursions may have posed a safety or security risk to their 

facilities or operations. We determined the data to be sufficiently reliable 

for our reporting purposes. In addition, we interviewed our selected 

aviation industry stakeholders and FAA officials to obtain their views on 

the safety risks posed by small UAS.

To examine the steps FAA has taken to safely integrate small UAS into 

the NAS, we reviewed FAA regulations, education outreach efforts, and 

planning and reporting documents related to UAS integration into the 

NAS. For example, we obtained and reviewed the agency’s 2013 

Roadmap for the Integration of UAS into the NAS, its fiscal years 2017 

and 2018 implementation plans for UAS integration into the NAS, its 2016 

Report to Congress on its UAS Detection Initiative, as well as rulemaking 

 3

AMA, founded in 1936, is the largest model aviation association and represents those 

who fly model aircraft for recreation and educational purposes.

4

GAO, Standards for Internal Control in the Federal Government, GAO-14-704G 

(Washington, D.C.: Sept. 10, 2014).
Appendix II: Objectives, Scope, and 

Methodology

Page 70 GAO-18-110 Small Unmanned Aircraft Systems

documents and aviation advisory and rulemaking committees’ reports. 

We also obtained FAA’s data on (1) the locations of small UAS registrants 

as of October 31, 2017, and (2) all enforcement actions taken against 

small UAS operators related to unsafe and unauthorized use through May 

2, 2018. We reviewed documentation about these data and the systems 

that produced them and interviewed knowledgeable FAA officials on how 

the data are collected, maintained, and verified, and we found the data to 

be sufficiently reliable for our reporting purposes. We also reviewed 

documentation from FAA’s Research and Development Advisory 

Committee and FAA’s Micro UAS Aviation Rulemaking Committee. In 

addition, we interviewed our selected aviation industry stakeholders about 

their perspectives on FAA’s actions. We also interviewed officials from 

NASA and reviewed agency documents about the agency’s development 

and testing of a traffic management system for small UAS.

To examine the extent to which FAA’s management of safety risks posed 

by small UAS has followed key principles of risk management, we 

identified five key principles and 15 supporting requirements from FAA’s 

policy on safety risk management and compared FAA’s risk management 

actions to the principles and requirements.5 We selected the 

requirements based on our judgement that following the requirements 

collectively should ensure that FAA’s policy objective for safety risk 

management “to provide supporting information for decision-makers by 

identifying hazards, analyzing safety risk, assessing safety risk, and 

developing controls to reduce risk to an acceptable level” would be met.

Several of the principles and requirements in FAA’s policies are similar to 

standards, principles, and guidelines in the federal internal control 

standards and the International Organization for Standardization’s Risk 

Management—Principles and Guidelines.6

We evaluated FAA’s risk management practices involved in carrying out 

selected agency efforts related to small UAS. We selected FAA efforts 

that involved development of regulations for small UAS or issuing 

exemptions or waivers to those regulations or other aviation regulations. 

The selected efforts were (1) development of the rule on registration of 

 5

The policy applies to all aspects of FAA’s oversight functions for making planned 

changes to the NAS and when potential and previously unidentified hazards and 

ineffective safety-risk controls are discovered. FAA, Safety Risk Management Policy, 

Order No. 8040.4A (Washington, D.C.: April 30, 2012).

6

GAO-14-704G and International Organization for Standardization, Risk Management -

Principles and Guidelines, ISO 31000:2009(E) (Geneva: Nov. 15, 2009).
Appendix II: Objectives, Scope, and 

Methodology

Page 71 GAO-18-110 Small Unmanned Aircraft Systems

small UAS; (2) the transitional process for authorizing commercial small 

UAS operations;7 (3) development of the small UAS regulations; (4) the 

process for waiving certain requirements in the small UAS regulations; (5) 

the process for approving requests from small UAS pilots for authorization 

to operate in airspace served by air traffic control; and (6) two Pathfinder 

projects.8 For each of these efforts, we assessed FAA’s practices against 

the five key principles and related supporting requirements by examining, 

as relevant, FAA’s safety-risk management documents, final rules, 

monitoring data, and other related documents, and by interviewing FAA 

officials. We then determined whether each requirement was followed—

meaning all or nearly all of FAA’s practices followed the requirement; 

partially followed—meaning some of FAA’s practices followed the 

requirement; or not followed—meaning all or nearly all of FAA’s practices 

did not follow the requirement. We then determined whether each 

principle was followed—meaning all three requirements under the 

principle were followed; not followed—meaning all three requirements 

under the principle were not followed; or partially followed—meaning that 

the principle was neither followed nor not followed. For example, if we 

found supporting evidence that FAA followed two of the three 

requirements under a principle but only partially followed the other 

requirement, we would determine that FAA partially followed the principle. 

One analyst performed the assessment, and a second analyst reviewed 

the assessment and resolved any disagreements with the first analyst.

To examine steps that selected federal agencies have taken to address 

security risks posed by small UAS operations in the NAS, we obtained 

and reviewed documents related to security risks posed by small UAS 

from FAA and other selected federal agencies including DHS, DOD, 

DOE, DOJ, DOI, and USDA. We also obtained and reviewed documents 

from FAA and the other federal departments and agencies related to 

 7

In September 2014, FAA began reviewing and approving applications for exemption of 

UAS from the agency’s aircraft airworthiness certification requirements—as required 

under section 333 of the 2012 act—to allow certain commercial UAS operations in the 

NAS prior to the agency’s implementation of its regulations for allowing routine small UAS 

use in the NAS. In broad terms, FAA’s aircraft airworthiness certification requirements are 

that aircraft (1) conform to the FAA-approved design for the aircraft’s type and (2) are in 

condition for safe flight.

8

We assessed FAA’s risk management practices for the Pathfinders with BNSF Railway 

and PrecisionHawk. However, we did not assess FAA’s risk management process for the 

Pathfinder with Cable News Network (CNN) because that process mainly involved FAA 

approving CNN’s operations under the agency’s transitional process for authorizing 

commercial small UAS use, and we assessed that process separately.
Appendix II: Objectives, Scope, and 

Methodology

Page 72 GAO-18-110 Small Unmanned Aircraft Systems

inter-agency coordination on managing security risks from small UAS and 

interviewed appropriate department and agency officials. In addition, we 

interviewed our selected aviation industry stakeholders about their 

perspectives on FAA’s and other federal agencies’ actions.

To describe actions that have been taken by selected foreign countries to 

address safety risks associated with the operation of small UAS, we 

reviewed publicly available information and interviewed FAA officials 

about leading countries in development of a regulatory framework for 

ensuring safe operations of small UAS in their respective domestic 

airspace. We also interviewed our selected aviation industry stakeholders 

about their perspectives on lessons that could be learned from other 

countries’ experiences. We selected five countries—Australia, Canada, 

France, Japan, and the United Kingdom (U.K.)—that are leaders in the 

development of a framework for the safe and secure operation of small 

UAS in their respective domestic airspaces. Our selection was based on 

the countries that were suggested by a leading UAS industry trade group; 

were most often mentioned in our stakeholder interviews; were among 

the leading countries in the development of a framework to ensure the 

safe and secure operation of small UAS in their respective domestic 

airspace—according to MITRE;9 have established classes or definitions 

of UAS; and are members of Joint Authorities for Rulemaking on 

Unmanned Systems (JARUS).10 We reviewed the regulations and policies 

of each country. We conducted semi-structured interviews with officials 

from the civil aviation authorities (CAA)—foreign countries’ counterparts 

to FAA—of Australia, Canada, France, and the United Kingdom and 

obtained written responses from the CAA of Japan. We obtained 

information and verified the information for their regulations, as well as 

discussed perspectives, experiences, challenges, and lessons learned 

about the countries’ approach to managing the safety risks associated 

with small UAS.

To expand our coverage beyond the initial five countries to achieve 

geographic diversity in our selections, we conducted a literature review 

and selected an additional five countries—China, Germany, Israel, 

Poland, and South Africa—based on publicly available information and 

 9

MITRE Corporation, UAS International Harmonization: A Comparative Policy 

Assessment of Selected Countries, Outcome 6, Output 4 (fiscal year 2014).

10Established in 2007, JARUS is a group of aviation experts from 50 countries, as well as 

the European Aviation Safety Agency (EASA), working to recommend a single set of 

technical, safety, and operational requirements for the safe operation of UAS.
Appendix II: Objectives, Scope, and 

Methodology

Page 73 GAO-18-110 Small Unmanned Aircraft Systems

reviewed documentation to summarize their regulations and policies, and 

other efforts regarding small UAS safety. These countries were also 

members of JARUS and had UAS regulations in place. We relied 

primarily on a study by the Law Library of Congress for this information.11

We did not contact these countries directly and did not independently 

verify this information with any of these countries’ CAAs or governments. 

The information on the foreign countries we reviewed cannot be 

generalized to other foreign countries, but offers insight into 

understanding the issues examined in this report. We also interviewed 

officials from the International Civil Aviation Organization, the European 

Aviation Safety Agency (EASA), and JARUS because these organizations 

play important roles in recommending or establishing UAS regulations in 

Europe or around the world.12

To identify policies and technologies that have been identified as 

potentially helping to address risks posed by small UAS in the NAS, we 

reviewed publicly available literature and obtained documents or 

interviewed officials from the following federal agencies: DOD, DHS, the 

Park Police and the Bureau of Reclamation within DOI, FAA, the Federal 

Bureau of Investigation, and NASA. We reviewed the information we 

obtained—the results of our semi-structured interviews and the 

documents obtained from aviation industry stakeholders and foreign 

CAAs—to identify available policy and technological tools that could

mitigate the risks associated with unauthorized small UAS operations. For 

example, we reviewed FAA’s final rule on small UAS operations and 

NASA’s concept of operations for an unmanned traffic management 

(UTM) system. We also reviewed MITRE presentations on counter UAS 

technologies and Sandia National Laboratories’ report, UAS Detection, 

Classification, and Neutralization: Market Survey 2015. We did not 

attempt to assert the appropriateness or the potential effect for 

implementation of such policies and technologies by FAA.

We conducted this performance audit from October 2015 through May 

2018 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 

 11Law Library of Congress, Regulation of Drones (April 2016).

12ICAO is the international body that, among other things, promulgates international 

standards and recommends practices in an effort to harmonize global aviation standards.
Appendix II: Objectives, Scope, and 

Methodology

Page 74 GAO-18-110 Small Unmanned Aircraft Systems

that the evidence obtained provides a reasonable basis for our findings 

and conclusions based on our audit objectives.
Appendix III: Federal Aviation Administration’s 

Coordination Efforts with Industry and 

Academic Stakeholders

Page 75 GAO-18-110 Small Unmanned Aircraft Systems

The Federal Aviation Administration (FAA) is coordinating with industry 

and academic stakeholders on efforts intended to inform its decisions for 

how to manage the safety risks associated with small unmanned aircraft 

systems (UAS) and to support and facilitate integrating small UAS into the 

national airspace system (NAS). Table 11 below describes examples of 

these efforts.

Appendix III: Federal Aviation 

Administration’s Coordination Efforts with 

Industry and Academic Stakeholders
Appendix III: Federal Aviation Administration’s 

Coordination Efforts with Industry and 

Academic Stakeholders

Page 76 GAO-18-110 Small Unmanned Aircraft Systems

Table 11: Examples of the Federal Aviation Administration’s (FAA) Efforts to Coordinate with Industry and Academic 

Stakeholders to Inform the Agency’s Management of Safety Risks Posed by Small Unmanned Aircraft Systems’ (UAS) 

Operations

Name of effort Description

UAS Test Sites In December 2013, FAA chose six UAS test sites across the country to provide research findings and 

data from operations by UAS companies and industry groups to help the agency develop regulations and 

operational procedures for the safe integration of UAS into the NAS. Several of the test sites are 

supporting FAA and the National Aeronautics and Space Administration’s (NASA) joint effort to determine 

the feasibility of a system for managing UAS traffic. 

Center of Excellence 

for UAS

In May 2015, FAA selected this research team led by Mississippi State University. In April 2017, the 

center completed a study that used computer simulations to estimate the effects of collisions between a 

small UAS and people and property on the ground. In November 2017, the center completed another 

study that used computer simulations supported by physical tests to estimate the effects of collisions 

between small UAS and manned aircraft.

Drone Advisory 

Committee

In May 2016, FAA announced the formation of this committee of government and industry stakeholders;

the committee is charged with advising FAA on the needs of UAS users and proposing ways for FAA to 

address issues affecting the efficiency and safety of integrating UAS into the NAS. In September 2016, 

the committee identified three initial high-priority issue areas: (1) the relative roles of the federal, state, 

and local governments in regulating the use of UAS; (2) a process for how FAA is approving new types of 

UAS operations; and (3) how FAA and other government activities related to integration of UAS in the 

NAS should be funded, and which of those activities should be privatized, if any.

Unmanned Aircraft 

Safety Team

In August 2016, FAA announced the creation of this team of government and industry stakeholders; the 

team is charged with analyzing safety data and developing recommendations to FAA on non-regulatory 

approaches for enhancing UAS safety. The team’s initial efforts include helping FAA develop an annual 

survey aimed at understanding the population of UAS registered and flown in the United States, 

developing a system to enable UAS operators to self-report hazardous situations anonymously, and 

having a small group of industry members volunteer flight data to examine the benefits of analyzing 

different datasets.a

UAS Identification 

and Tracking Aviation 

Rulemaking 

Committee

In June 2017, FAA announced the formation of the committee to advise FAA on issues such as UAS 

identification and tracking, air traffic management for UAS, concerns and authorities of local law

enforcement, and potential legal considerations. The committee includes representatives from the UAS 

and manned aviation industries, researchers, standards groups, and local law enforcement.

Probabilistic Risk 

Assessment for UAS 

Integration

In April 2017, FAA contracted with the National Academy of Sciences to complete a study by July 2018 

on the potential use of probabilistic risk assessmentsb by FAA to streamline the integration of UAS into 

the NAS.c

Source: GAO summary of FAA information. l GAO-18-110

a

The team is modeled on the Commercial Aviation Safety Team, whose work, according to the team, 

helped reduce the fatality rate of commercial air travel in the United States by 83 percent from 1998 

to 2008.

b

FAA entered into this contract in response to Section 2213 of the FAA Extension, Safety, and 

Security Act of 2016, which required that, by August 14, 2016, FAA arrange for the National 

Academies of Sciences, Engineering, and Medicine to conduct such a study, with the results to be 

provided to Congress by July 15, 2017.

c

According to NASA and the Department of the Interior’s Bureau of Safety and Environmental 

Enforcement, probabilistic risk assessment is a systematic and comprehensive methodology to 

evaluate risks associated with complexly engineered technological entities. This assessment involves 

the assignment of numeric values in the assessment of probability and consequence and attempts to 

consider all events and consequences in one assessment, allowing for a more robust estimation of 

risk.
Appendix IV: Statutory and Regulatory 

Requirements for Small Unmanned Aircraft 

Systems’ Operations in Select Countries

Page 77 GAO-18-110 Small Unmanned Aircraft Systems

We selected five countries—Australia, Canada, France, Japan, and the 

United Kingdom (U.K.)—for review. The information below on these 

countries is based on our review of each country’s regulations and 

policies pertaining to small unmanned aircraft system (UAS) operations 

and interviews of officials representing the civil aviation authorities (CAA) 

of four of the selected countries and written responses from the fifth. In 

addition, we reviewed the regulations and actions associated with UAS 

operations of China, Germany, Israel, Poland, and South Africa.1 The 

information below on these countries is based primarily on a study by the 

Library of Congress that summarized these countries’ efforts regarding 

small UAS safety.2 We did not interview CAA or other officials from these 

additional countries and we did not independently verify this information 

with any of the CAAs or governments See appendix II for further details 

on our scope and methodology.

Australia does not regulate small UAS used for recreational purposes. 

Recreational small UAS in Australia are defined as weighing 4.4 to 55 

pounds and very small UAS as weighing less than 4.4 pounds. According 

to officials from Australia’s CAA, the agency generally leaves oversight of 

recreational operations to associations and clubs and prefers to 

emphasize education and conduct safety promotions. The Australian 

CAA’s general operating guidelines are that recreational small UAS be 

operated in the visual line of sight of the operator, in unpopulated areas to 

avoid flying over people or near large groups of people, at or below 400 

feet, and not within 3 miles of the movement area of a controlled airfield.

Australia has regulated commercial UAS since 2002, and Australia’s CAA 

is responsible for enforcing the provisions of Australian law relevant to the 

operations of commercial small UAS. Commercial operators must 

acknowledge they are aware of and will follow the CAA’s regulations. For 

example, operating a UAS in a way that is hazardous to another aircraft, 

another person, or property could subject the operator to a penalty. The 

operating conditions for commercial UAS weighing less than 4.4 pounds 

include flying only during the day and in the visual line-of-sight of the 

operator and below 393 feet. Flying is not permitted within 3.4 miles of an 

air-traffic-controlled airport; over populous areas such as beaches, parks, 

and sports fields; or near emergency operations, such as firefighting, 

 1

These countries were selected to provide additional geographic dispersion to the initial 

group of selected countries. 

2

Law Library of Congress, Regulation of Drones (April 2016).

Appendix IV: Statutory and Regulatory 

Requirements for Small Unmanned Aircraft 

Systems’ Operations in Select Countries

Australia
Appendix IV: Statutory and Regulatory 

Requirements for Small Unmanned Aircraft 

Systems’ Operations in Select Countries

Page 78 GAO-18-110 Small Unmanned Aircraft Systems

accidents, or search and rescue. Also, operators must notify the CAA of 

their intention to conduct operations and the location where the 

operations will take place. According to CAA officials, the CAA has been 

attempting to coordinate with state police in the hope that the police can 

provide them with evidence of such violations.

In March 2017, Transport Canada, Canada’s CAA, announced interim 

measures governing the use of recreational aircraft heavier than 0.55 

pounds and up to 77 pounds. According to these interim measures, 

recreational aircraft must be operated within visual line of sight and no 

higher than 300 feet above ground level. They also must not operate less 

than 250 feet from structures and unassociated people and within 5.6 

miles from the center of an airport. Contravention of these measures 

could result in fines for operators, whether individuals or corporations.

According to officials from the CAA, the agency has also generally 

emphasized education and enforcement for recreational operators. The

CAA officials also launched a national safety awareness campaign for 

UAS to help Canadians better understand areas where it may be illegal or 

unsafe to fly a UAS and set up a web page that provides guidelines and 

other information for UAS operators. In December 2016, the CAA 

launched an online incident-reporting tool, and also collaborates with the 

aviation and real estate industries and is trying to engage a broad 

spectrum of users by hosting public UAS events, known as drone fairs. 

The CAA has also partnered with retailers to provide safety information at 

the point of sale.

Under the current Canadian commercial regulations, the CAA issues 

special flight-operating certificates to commercial UAS operators on a 

case-by-case basis. Since November 2014, UAS that weigh up to 25 

kilograms can be commercially operated with an exemption to the 

requirement for a special flight-operating certificate while subject to 

specific operating conditions. In May 2015, the CAA published a notice of 

proposed amendment for small UAS of 57 pounds or less operated under 

visual line of sight. Under the proposed new framework, there would no 

longer be a distinction between commercial and recreational operations. 

Other proposed changes included exclusion for modeling associations 

with robust safety guidelines, marking and registration for small complex 

UAS, and requiring liability insurance for all categories of UAS.

According to officials from the CAA, the agency enforces UAS laws and 

its regulations through collaboration with law enforcement and works 

primarily with the Royal Canadian Mounted Police (which is similar to the 

Canada
Appendix IV: Statutory and Regulatory 

Requirements for Small Unmanned Aircraft 

Systems’ Operations in Select Countries

Page 79 GAO-18-110 Small Unmanned Aircraft Systems

U.S. Federal Bureau of Investigation). CAA is considering encouraging 

local law enforcement to detect, track, and identify UAS operators who 

are in violation of laws or regulations. The operation of a UAS in Canada 

without a special flight-operating certificate may result in fines for 

individual and corporate operators.

France has issued guidelines to its recreational operators in the form of a 

10-point letter. The guidelines included such requirements as not flying 

close to airports or over people and not flying below 492 feet. The 

guidelines were issued through France’s largest UAS manufacturer, 

Parrot, and an association of operators.

France published its first commercial UAS regulations in 2012, and new 

regulations became effective in January 2016. According to officials from 

the France’s CAA, in France, UAS are primarily used for commercial 

operations, such as photography, infrastructure inspections, and 

surveying. Commercial small UAS operators must request operating 

approvals from the French CAA; requests are evaluated on a case-bycase basis. France also requires a design certification and safety 

requirements for some types of UAS, depending on weight and use 

scenarios.

All civilian UAS operations are subject to geographic restrictions, primarily 

to protect people, property, and other aircraft. For instance, UAS may not 

be flown over public areas of urban zones without governmental approval 

and are required to fly under certain altitudes. Failure to comply with 

design and safety requirements is punishable by up to 1 year in jail and a 

fine.

In 2015 and 2016, Japan promulgated UAS regulations to protect the 

safety of flying aircraft and people and properties on the ground. Under 

the 2015 regulations, Japan does not distinguish between recreational 

and commercial UAS operations. The scope and requirements of the 

regulation depend on the risk level of the UAS operation, regardless of 

the purpose of the operation. These UAS are allowed to operate in 

daytime only, within visual line of sight of the operator, at a distance of 98 

feet from persons or properties, and never over event sites where many 

people gather. If the rules are violated, the UAS operator could be liable 

for a fine. To fly a UAS over areas where air traffic is expected, such as 

airports, above 492 feet, and over densely populated areas, UASs’

operators are required to apply for permission from the country’s civil 

aviation authority. The 2016 regulation prohibits flying UAS within a 328-

yard radius of designated facilities, including the Prime Minister’s office 

France

Japan
Appendix IV: Statutory and Regulatory 

Requirements for Small Unmanned Aircraft 

Systems’ Operations in Select Countries

Page 80 GAO-18-110 Small Unmanned Aircraft Systems

building, the Supreme Court building, the Imperial Palace, embassies, 

and nuclear facilities. Flying a UAS over a designated facility can result in 

the destruction of the UAS and is punishable by a prison term or a fine.

The U.K. distinguishes between recreational and commercial (known as 

“aerial work”) small UAS operations and regulates both types of 

operations. The regulations provide basic safety measures. For example, 

UAS are to be flown below 400 feet, 150 feet from people and property, 

not near airports, and not near other aircraft. To ensure that the public is 

aware of the regulations, the U.K. CAA’s website includes its “drone 

code”. In addition, the U.K.’s main air-traffic provider, NATS, has 

developed a web site, http://dronesafe.uk/, and Drone Assist, a new 

drone-safety application. An individual who operates a drone for 

commercial purposes must obtain a license from the CAA.

The U.K. CAA is responsible for ensuring compliance with the Air 

Navigation Order and works with the police and other agencies in doing 

so. Most enforcement actions by the CAA are aimed at operators who 

use UAS for commercial purposes without a license. In December 2015, 

the CAA announced that it would begin taking enforcement actions 

against recreational operators who do not follow the regulations. Failing to 

observe the regulations can result in a criminal prosecution and a fine.

China issued UAS provisions in December 2015. The provisions divided 

UAS into seven categories based primarily on weight. The categories do 

not distinguish between recreational and commercial operations. The 

smallest category of UAS—those that weigh less than 3.3 pounds—are 

required to be operated safely and to avoid causing injury to others, but 

are not otherwise subject to the UAS Operation Provisions. For the 

remaining categories of UAS, the Provisions include the requirements 

that UAS be operated in the daytime, within visual line of sight, and with 

insurance for covering liability for third parties on the ground. The 

Provisions require a pilot-in-command who is directly in charge of the 

operation and has the right to make final decisions

The Provisions also set up an online, real time supervision that has two 

components: the electric fence and the UAS cloud. The electric fence is a 

hardware and software system that stops aircraft from entering certain 

areas. The UAS cloud is a dynamic database management system that 

monitors flight data in real time. It has an alarm function that is activated 

when UAS connected to it fly into the electronic fence.

United Kingdom

China
Appendix IV: Statutory and Regulatory 

Requirements for Small Unmanned Aircraft 

Systems’ Operations in Select Countries

Page 81 GAO-18-110 Small Unmanned Aircraft Systems

German law addressed UAS in 2007. Germany defines UAS as 

unmanned aircraft that that are not used for hobby or recreational 

purposes. UAS used for hobby or recreational purposes are defined as 

model aircraft. Authorization from the German state in question is 

required to operate a UAS that weighs more than 11 pounds. There are 

two types of these authorizations. A general authorization is granted for 

UAS that do not weigh more than 11 pounds and do not have a 

combustion engine. A specific authorization may be obtained for UAS that 

weigh between 11 and 55 pounds, but only for the limited time and place 

specified in the authorization. There are also general restrictions to be 

observed when operating a UAS in Germany. The UAS cannot weigh 

more than 55 pounds, must be kept within visual line of sight, must be 

flown below 328 feet above ground, cannot be flown within about 1 mile 

of an airport, unless a special permit is granted, and may not fly over 

people or public gatherings.

In Israel, the CAA licenses and supervises civilian UAS flight operations, 

and CAA directives regulate UAS activities. For example, UAS flights over 

populated areas must be conducted at 5,000 feet or higher, unless there 

is special prior approval, and they generally must not be operated in the 

same airspace as manned aircraft. UAS are also generally required to 

have specific equipment, including a properly operating transponder. 

According to the Aviation Law, an individual working in the aviation 

profession (including flying, inspecting, and instructing) is required to be 

licensed, including UAS operators. Violation of licensing requirements 

results in the same penalties that apply to manned aviation, in which the 

penalties range from administrative fines to imprisonment.

Poland has regulated the operation of UAS in Polish airspace since 2013. 

Further, commercial UAS pilots must have a certificate of competency 

from the CAA; this certificate is issued to those who have passed a 

medical check-up, taken theoretical and practical tests, and have 

insurance. To operate in visual line of sight, the applicant must obtain a 

certificate of competency for which he or she signs a declaration of 

knowledge of relevant regulations and basic theory and passes 

theoretical and practical tests. To operate beyond visual line of sight, the 

applicant must successfully pass training courses in addition to passing 

the theoretical and practical tests to obtain the certificate of competency. 

Currently, beyond visual line-of-sight flights are limited to dedicated and 

segregated airspace. The certificate of competency can also be limited to

certain UAS weight ranges (e.g., less than 4.4 pounds to less than 330 

pounds) and classes of UAS (e.g., airplane, helicopter, or multirotor).

Germany

Israel

Poland
Appendix IV: Statutory and Regulatory 

Requirements for Small Unmanned Aircraft 

Systems’ Operations in Select Countries

Page 82 GAO-18-110 Small Unmanned Aircraft Systems

Since 2015, South Africa has regulated UAS. South Africa permits 

different types of UAS operations: private, commercial, corporate, and 

non-profit. South Africa, defines a UAS as an unmanned aircraft piloted 

from an pilot’s station, excluding model aircraft (an unmanned vehicle 

used for competition, sport, or recreational purposes) and toy aircraft 

(intended for use in play by children). A private operation is the use of a 

UAS for an individual’s personal and private purpose where there is no 

commercial outcome, interest, or gain. Private operations must be 

conducted with UAS weighing less than 15.4 pounds, cannot be flown 

more than 400 feet above the ground, and only in restricted visual line of

sight. Non-private operations are allowed with the issuance of a remotely 

piloted aircraft letter of approval, a certificate of registration, a remote pilot 

license, and a UAS operator certificate. Only operator certificate holders 

are permitted to operate beyond visual line of sight and directly over 

people).

South Africa
Appendix V: Comments from the Department

of Transportation

Page 83 GAO-18-110 Small Unmanned Aircraft Systems

Appendix V: Comments from the Department 

of Transportation
Appendix V: Comments from the Department 

of Transportation

Page 84 GAO-18-110 Small Unmanned Aircraft Systems
Appendix VI: GAO Contact and Staff

Acknowledgments

Page 85 GAO-18-110 Small Unmanned Aircraft Systems

Heather Krause at (202) 512-2834 or KrauseH@gao.gov

In addition to the contact named above, the following individuals made 

important contributions to this report: Gerald L. Dillingham, Ph.D. 

(Director); Vashun Cole, Assistant Director; David Goldstein, Analyst-inCharge; Melissa Bodeau; Russell Burnett; Carole Cimitile; Camilo Flores; 

James Geibel; Richard Hung; Joshua Ormond; William Reinsberg; Amy 

Rosewarne; and Pamela Vines.

Appendix VI: GAO Contact and Staff 

Acknowledgments

GAO Contact

Acknowledgements

(100367) 
The Government Accountability Office, the audit, evaluation, and investigative 

arm of Congress, exists to support Congress in meeting its constitutional 

responsibilities and to help improve the performance and accountability of the 

federal government for the American people. GAO examines the use of public 

funds; evaluates federal programs and policies; and provides analyses, 

recommendations, and other assistance to help Congress make informed 

oversight, policy, and funding decisions. GAO’s commitment to good government 

is reflected in its core values of accountability, integrity, and reliability.

The fastest and easiest way to obtain copies of GAO documents at no cost is 

through GAO’s website (https://www.gao.gov). Each weekday afternoon, GAO 

posts on its website newly released reports, testimony, and correspondence. To 

have GAO e-mail you a list of newly posted products, go to https://www.gao.gov

and select “E-mail Updates.”

The price of each GAO publication reflects GAO’s actual cost of production and 

distribution and depends on the number of pages in the publication and whether 

the publication is printed in color or black and white. Pricing and ordering 

information is posted on GAO’s website, https://www.gao.gov/ordering.htm. 

Place orders by calling (202) 512-6000, toll free (866) 801-7077, or 

TDD (202) 512-2537.

Orders may be paid for using American Express, Discover Card, MasterCard, 

Visa, check, or money order. Call for additional information.

Connect with GAO on Facebook, Flickr, Twitter, and YouTube. 

Subscribe to our RSS Feeds or E-mail Updates. Listen to our Podcasts. 

Visit GAO on the web at https://www.gao.gov. 

Contact:

Website: https://www.gao.gov/fraudnet/fraudnet.htm

Automated answering system: (800) 424-5454 or (202) 512-7470

Orice Williams Brown, Managing Director, WilliamsO@gao.gov, (202) 512-4400, 

U.S. Government Accountability Office, 441 G Street NW, Room 7125, 

Washington, DC 20548

Chuck Young, Managing Director, youngc1@gao.gov, (202) 512-4800

U.S. Government Accountability Office, 441 G Street NW, Room 7149 

Washington, DC 20548

James-Christian Blockwood, Managing Director, spel@gao.gov, (202) 512-4707

U.S. Government Accountability Office, 441 G Street NW, Room 7814, 

Washington, DC 20548

GAO’s Mission

Obtaining Copies of 

GAO Reports and 

Testimony

Order by Phone

Connect with GAO

To Report Fraud, 

Waste, and Abuse in 

Federal Programs

Congressional 

Relations

Public Affairs

Strategic Planning and 

External Liaison

Please Print on Recycled Paper.