Public safety agencies operating unmanned aerial systems (commonly referred to as "drones") across the United States have reaped substantial benefits from these remotely piloted and programmable aircraft. Drones are used to locate lost persons, conduct reconnaissance missions during SWAT operations, and provide aerial photographs and video of traffic accident sites and crime scenes.
But what happens when a drone falls into the hands of an aggressive entity?
Consider this scenario:
Local law enforcement officers are providing security for a large outdoor music festival in late spring somewhere in the southern United States. Halfway through the headlining act's set, a small, four-bladed drone begins hovering over the crowd. A fine mist begins emanating from a container mounted to the bottom of the drone. Taken by surprise, concertgoers beneath the drone react with fear and begin rubbing their eyes, shielding themselves, and running from the area. The initial disruption causes panic from other members of the crowd, who then begin to flee the area.
Of course, this hasn't happened yet. But it could. Even the latest generation of hobby drones could be weaponized by terrorists or criminals as bomb or chemical delivery systems. And it's already happening in some of the world's most dangerous areas.
- American forces recovered video from a seized drone that showed it being armed with free-falling explosives. In the video, the ISIS drone departed from the insurgents' location, overflew a small unit of soldiers, and dropped its explosive payload. Thankfully, the noise of the drone caught the soldiers' attention, and they were able to take cover and initiate cover fire before any serious damage was inflicted.
- In August, Venezuelan President Nicolas Maduro was reportedly the target of a drone attack during a political rally. Maduro was forced to take shelter after two explosive-laden drones detonated nearby. Characterized as an assassination attempt by the Venezuelan government, the attack ended without any fatalities. However, it did result in pandemonium as attendees were sent fleeing for cover. While both drones were armed with explosive devices, only one came close to detonating near the Venezuelan President. The other struck a building, causing it to crash and explode. Law enforcement officials arrested six individuals suspected of being connected to the attack.
- There's also evidence that terrorists are planning to use drones for attack. Open source intelligence reports have returned photographs, video, and detailed ISIS literature about weaponizing commercial-grade drones.
Incidents like this are why some American law enforcement agencies are asking certain questions: How can we adequately respond to the potential public safety threat that could be presented by drones? What tools do we have available to legally mitigate the threat of drone attacks?
The concern about how to counter drone attacks has been present among public safety officials during the rapid development of drone technology. But instituting drone countermeasures in the United States, compared to other countries, has been difficult given the stringent legal tests each piece of technology must pass.
Multiple legal challenges exist for governmental and non-governmental organizations seeking mitigation strategies. Passive counter-drone technology involving the detection and identification of drones is becoming increasingly popular through RF sensing, video algorithm detection, acoustic frequency monitoring, or a combination of all three. To date, active counter-drone technology is still illegal, with few specific exceptions.
Congress enacted provisions for the Department of Defense and Energy to "use reasonable force to disable, damage, or destroy" drones over select facilities through the National Defense Authorization Act of 2017. Congress later expanded the authority to the Department of Defense to "detect, monitor, and track" as well as "disrupt control of" or "seize" drones through the National Defense Authorization Act of 2018.
United States Code delegates the statutory authority for aviation to the Federal Aviation Administration (FAA). Accordingly, the FAA established the definition of an aircraft under 49 USC § 40102 as "any contrivance invented, used, or designed to navigate, or fly in, the air." In Huerta v. Pirker (2014), the court affirmed the FAA's opinion that drones are considered aircraft, and therefore covered by the same regulations as manned aircraft. Realizing the immediate threat to national security, Congress has provided relief to the Department of Defense for criminal acts covering aircraft piracy (49 USC § 46502) and the entire criminal code (all of USC Title 18).
Active counter-drone conceptual technologies involve overpowering the control segment of the drone, jamming the drone's control link, and a variety of kinetic countermeasures to physically disable the drone. Unfortunately, with the exception of the allowances afforded to the Department of Defense, these measures are illegal for use by other governmental and non-governmental organizations. A series of FAA and FCC regulations and federal laws prohibits the counter-drone systems developed by a number of domestic research and development organizations being used by law enforcement.
A major concern with deploying kinetic and non-kinetic technologies against drones exists in the indirect results of the drone's disruption.
Deploying counter-drone technology by force (including kinetic methods, such as with a firearm) to disrupt a drone's flight (including interfering with the operator of a drone) is potentially an act of aircraft piracy under 49 USC § 46502 and punishable by 20 years of imprisonment. If the drone is disrupted to the point that it is damaged or destroyed, the Department of Justice considers the act a violation of 18 USC § 32, "aircraft sabotage."
Given the scenario demonstrated at the beginning of this article, an ill-advised solution is to shoot the drone out of the sky. Care must be given to the end result of firing a firearm into the air toward a moving drone at a variable distance. Whether or not the cartridge fired at the drone contains a lethal projectile, the resultant reaction has the potential to damage property or injure people below the drone. If the cartridge in the example provided contains a small net deployed by a shotgun shell fired from a moderate distance, two outcomes are possible: 1) the cartridge's payload will miss the target and fall into the crowd beyond the drone or 2) the payload will successfully deploy on the target, causing the inert drone to crash, potentially into the crowd below.
A collaborative study conducted between multiple collegiate institutes for the Federal Aviation Administration's UAS Center for Excellence Task Force ("UAS Ground Collision Severity Evaluation" Revision 2. Final Report for the FAA UAS Center of Excellence Task A4) demonstrated a failed drone's impact to the human body. The resultant impact of a plastic rotary drone to the crash test dummy was between 9 foot-pounds and 233 foot-pounds, depending on the angle and speed of the falling drone. The study's experiments were conducted under the assumption that the drone's rotating blades would not cause any further damage to the crash test dummy.
In 2014, the Sydney Morning Herald reported that a marathon runner received serious lacerations requiring multiple stitches after a drone providing video coverage of the marathon experienced a communications failure and fell onto the runner. During a family event in Gifu, Japan, an 8-pound, 30-inch drone distributing candy to attendees suffered a communications link failure and crashed into a crowd of bystanders. At least six people suffered injuries, according to Kyodo News.
What You Can Do
A drone hovering over a crowd with the appearance of a payload that can be articulated as an imminent threat to the lives of the attendees or other officers may require an appropriate use of force in line with the agency's use-of-force policy. But the law doesn't permit it. So what can you do?
The utilization of non-kinetic methods for mitigating drones requires further examination to determine effectiveness and practicality. Whether or not injury occurs, the problem continues to lie within the statutory violations of signal interference between the drone operator and the drone. Federal law prohibits the "willful and malicious injury or destruction of the works, property, or material of any radio, telegraph, or cable, line, station, or system, or other means of communication…" under 18 USC § 1362. Additionally, when commands are sent via radio signal in lieu of GPS, the Communications Act of 1934, by means of 47 USC § 333, states that "no person shall willfully or maliciously interfere with or cause interference to any radio communications of any station licensed or authorized by the United States government."
The process of "spoofing" a drone by seizing control of it remotely involves emitting a signal, which confuses the drone and makes it believe the new signal is legitimate. By doing so, the counter-drone technology acquires the content of the broadcast signal to issue alternate control instructions, which violates the Wiretap Act defined in part by 18 USC § 2510.
When the legalities of counter-drone technologies have been sorted out by lawmakers, the next hurdle for law enforcement agencies will be evaluating the most effective method of counter-drone technology for their agency. While counter-drone technologies go through their development and due process, it is important to remember that law enforcement officers are still empowered to act on a threat with an appropriate level of force.
A drone hovering over a crowd without the appearance of a payload may be worth monitoring. If the pilot of the drone is located, it may be prudent to engage them in a discussion about the safety considerations of their operation. Further education and follow-up with the pilot may be necessary and can be provided by contacting the local Federal Aviation Administration Law Enforcement Assistance Program Special Agent through the appropriate law enforcement channels.
Michael Hamann is a certified air traffic control specialist with the Federal Aviation Administration. He holds a master of arts degree in emergency management and homeland security from Arizona State University and a Bachelor of Science Degree in aeronautical studies from Embry-Riddle Aeronautical University. His views do not necessarily represent those of the Federal Aviation Administration.