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4 C H A P T E R 1 Brief History of Unmanned Aircraft Systems Although the Wright Brothersâ epic manned first flight on December 17, 1903, marked the beginning of aviation, there were unmanned efforts dating back to the late 1800s. On August 22, 1849, Austria sent an unmanned balloon filled with explosives in an attack on Venice, Italy. Although this event is recognized as the first use of unmanned aircraft (UA), this does not meet the modern definition of UA, which is a controlled, remotely piloted aircraft. The first unmanned aircraft to fly was known as the Hewitt-Sperry and was controlled by a gyroscope. This UA was intended to be used as a flying bomb (Figure 1). Following the Hewitt-Sperry, in 1918, the Kettering Bug was built by the U.S. Army and designed as an aerial torpedo guided by gyroscopic controls. This UA was a more efficient flying bomb, capable of hitting targets 40 miles away (Figure 2). However, the war ended before this unmanned aircraft could see active duty. The benefits were clear and in 1937, the U.S. Navy developed the Curtiss N2C-2 UA. Two years earlier, in 1935, the British developed the âQueen Bee,â serving as a radio-controlled target. The feasibility of UA had been realized (Vyas 2018). Unmanned Aircraft Systems Defined Although the general public uses the term drone when referring to UA, and the term remotely piloted aircraft (RPA) is also used, the terms UA or unmanned aircraft systems (UAS) are used in this synthesis report. Airports intending to own and operate UA, or allow for UA operations by others, benefit from having UAS-knowledgeable staff. Although more in-depth guides exist, it is important to review the basic technology of UAS within this chapter. For an in-depth primer in UAS, readers are encouraged to review ACRP Report 144: Unmanned Aircraft Systems (UAS) at Airports: A Primer (Neubauer et al. 2015). The unmanned or remotely piloted aircraft that was once solely the purview of the military is now within the reach of almost everyone. Even children may own UA, often in the form of a widely available small quadcopter. Hundreds of manufacturers are producing UA of all sizes. When considering the complete systems to operate UA, the global sales of UAS grew to 2.2 million, with revenue of $4.5 billion in 2016. In the United States alone, 2.4 million rec- reational UA were purchased in 2016, which is more than twice the 1.1 million sold in 2015 (Glaser 2017). The FAA reports that, as of July 2018, almost 1 million recreational UA have been registered with the FAA, while just over 200,000 commercial UA have been registered. It appears the UA industry is here to stay (FAA 2018a). Introduction
Introduction 5 UAS usually comprise the following four main elements: â¢ Unmanned aircraftâCommonly referred to as UA, this is the actual aircraft. â¢ Pilot and crewâIncludes pilot, sensor and payload operators, visual observers, mission com- manders, and others, depending on the operation. â¢ Data link and control methodsâSuch as 900 MHz, 2.4 GHz, Wi-Fi, satellite links, or ground relay line-of-sight network. â¢ Launch and recovery and otherâSupport equipment, payloads, flight terminal systems, and launch and recovery equipment (Oliver 2016, p. 33). Figure 1. Hewitt-Sperry unmanned aircraft. Figure 2. Kettering Bug (Source: National Museum of the U.S. Air Force).
6 Current Landscape of Unmanned Aircraft Systems at Airports A small unmanned aircraft (SUA) defined by the FAA as weighing at least 0.55 lb (250 g) and less than 55 lb (25 kg), would not represent an extensive system. A micro UAS (small enough to fit into the palm of a hand) would require even less. However, even the smallest UAS requires each of the four elements aboveâaircraft, operator/pilot, data link, and launch and recovery protocol. Unmanned Aircraft The unmanned, or remotely piloted, aircraft includes the airframe, propulsion system (including energy, in the form of battery power or fuel), and the payload. According to Armstrong (2010), UA vary considerably in âphysical size, weight, range, speeds, application, and enduranceâ (p. 1). In fact, there are numerous ways to classify UA, including size, range, endurance, and maximum takeoff weight. Unmanned Aircraft Types UA may be fixed wing (in which the lifting surfaces are stationary) or rotary wing (in which the lifting surfaces rotate). Traditionally, fixed-wing UA enjoy longer flight duration, but may have more advanced launch and recovery requirements (to include runway, catapult, and cap- ture nets). Fixed-wing UA often have the ability to fly at higher altitudes and carry greater pay- loads with greater range. On the other hand, rotary-wing aircraft have minimal launch and recovery requirements (no runway needed), and have the ability to hover and detect objects at close or far range from a fixed position (Brungardt and Barnhart 2016 in Marshall et al. 2016). The range of UA types includes very large group 5 UA that weight more than 1,320 lb and operate at over 18,000 ft mean sea level to the micro UA that weigh several ounces and can be held in the palm of a hand. Survey data indicated that airports active with UAS generally use sUA, which weigh less than 55 lb and operate below 400 ft above ground level (AGL) and at a speed below 100 mph (87 kt), in compliance with 14 C.F.R. Part 107. Average characteristics of sUA are presented in Table 1. Mission demands often dictate the UA to be used. Payload capacity and endurance are the most salient features for airport operators. For missions requiring longer endurance, such as airport perimeter inspections, a fixed-wing UA might be used. For even greater endurance, Aircraft Characteristic sUA Fixed-Wing UA VTOL UA Electric UA Internal Combustion sUA Cruise speed, kt 28.5 34.9 21.8 25.3 42.2 Maximum speed, kt 49.1 62.1 3.53 44 71 Endurance, min (h) 129.7 (2.2) 217.7 (3.6) 58.7 (0.9) 67 (1.1) 494.2 (7.4) Range, SM 112.9 175.7 44.9 42.3 408.5 Payload capacity, lb 6.8 6.8 6.9 5.2 13.1 Notes: Electric sUA include both fixed wing and VTOL with electric propulsion. Internal combustion sUA include both fixed wing and VTOL with internal combustion engine propulsion. kt = knots; SM = statute mile; VTOL = vertical takeoff and landing. Source: Terwilliger et al. 2017. Table 1. Average sUA characteristics.
Introduction 7 a fixed-wing UA with internal combustion engine could be used. Consider that a taxiway or runway might be needed to launch the fixed-wing aircraft. For missions requiring the ability to hover, such as monitoring an aircraft accident scene, a vertical takeoff and landing (VTOL) UA might be used. If endurance is factor, a VTOL with internal combustion engine might be used. In all cases, factors such as price, availability, and command and control must also be considered. Propulsion Propulsion systems vary. Many of todayâs UA are powered electronically via battery pack. Although this allows for quiet operation, endurance is greatly affected because battery technol- ogy is not at a point that allows for extended operation. That being said, often a fixed-wing battery-powered UA will have greater endurance than a rotary-wing battery-powered UA. For the greatest endurance, some UA are equipped with one or more fuel-driven engines. Generally, this is more common in the category of larger UA. Fuel is heavy and so are internal combustion engines. Furthermore, fueling UA adds another factor to launch and recovery. In the world of UA, reverse engineering is recommended for selecting an appropriate UA. In other words, first determine the payload required for the mission. Second, determine the UA that is capable of carrying that payload to successfully complete the mission. Otherwise, an underpowered aircraft might be acquired that would be insufficient to carry the required pay- load, thus preventing mission completion. Finally, consider the entire system (UAS) necessary to support the operation of the chosen UA. Payloads Payloads for UA are often presented in three categories: (a) still imagers, (b) full motion video, and (c) other payloads. Still imagers may be in the form of simple cameras or can include specialized spectral imag- ers. Still imagers capture an image at a point in time, but may be capable of capturing multiple images per second. Generally, a stable platform, such as VTOL, is most effective for still imagers. Often, remote sensing is best performed using a still imager. Metadata are also generally collected with still images. Such metadata may include date, time, GPS coordinates, or shutter speed (Marshall et al. 2016). Once images are captured at 15â20 frames per second and greater, the imaging process is considered to be full motion video (FMV). Cinematic-quality video is captured at 24 frames per second. FMV captures motion in real time. This is especially helpful to watch events as they unfold in real time, such as a wildlife migration across airport property. Most FMV imagers are of lower resolution than still imagers, with even 1080p videos containing only 1/15th the image quality of a high-quality still imager. Similarly to still imagers, FMV imagers can also capture metadata (Marshall et al. 2016). Although capturing images, whether still or moving, is quite common among UA opera- tors, UA may be outfitted with other payloads as well. Other payloads can include air sampling devices, communications relays, or radars. These are generally very specific payloads for specific purposes. It is most important to ensure that the correct data are being collected with the most appropriate payload (Marshall et al. 2016). Pilot and Crew The extent of crew required varies from one person serving as pilot, sensor operator, and launch and recovery specialist with UAS, to multiple crew of a dozen or more in support of a large UAS. A remote pilot is needed to maneuver the aircraft, manipulating controls to ensure
8 Current Landscape of Unmanned Aircraft Systems at Airports mission completion. Even in a fully automated mission, a pilot programs the mission to ensure that the aircraft will fly a predetermined route. The sensor operator controls the various sensors, manipulating payload to collect data as determined by the mission. Finally, depending on the launch and recovery requirements of the UA, additional personnel might be needed to ensure successful launch and safe recovery of the UA. Crew requirements vary based on UA and mission. Data Link and Control Methods UA are controlled via one or more methods that exist on a continuum of autonomy. As shown in Figure 3, this continuum ranges from completely autonomous vehicles to remotely piloted vehicles (Armstrong 2010, p. 14; Blanks 2016, pp. 21â22). With autonomous control, the UA autonomously flies a mission based on the task assigned. The UA will automatically react to threats and maintain situational awareness. The control link is based on information rather than control. Often, this degree of autonomous control is present only in large UAS. With fully automated control, the operator controls the aircraftâs flight path via indirect, assisted control. A graphical user interface is typical with fully automated systems. This inter- face provides an aerial view of the area of the mission, which allows the operator to plan the mission through the softwareâs mission planning tools. Based on this planned route of flight, the aircraftâs autopilot determines the control surface and throttle inputs necessary to complete the mission. Although fully automated systems require minimal skill in controlling the UA, the sometimes complex software systems do require some time to learn. Even so, the benefits of automated orbits and mapping missions are well worth the effort to learn the software interface (Blanks 2016). With stabilized semi-automated control, the operator controls the aircraft with direct, assisted control of the aircraftâs flight path. Generally, the operatorâs inputs are routed through Autonomous â¢Vehicle flies a mission based on task and has the ability to autonomously react to threats and its situation awareness. â¢Interface between ground and vehicle is task and information based, not control based. Automated â¢Vehicle flies a pre-programmed route through waypoint navigation. â¢ Landing is controlled by ground station. Stabilized Semi-Automated â¢Vehicle takes off and lands under control of a ground based pilot and flies on automatic pilot using waypoint navigation. Manual Remotely Piloted Aircraft â¢UAS pilot manually controls the vehicle remotely. â¢Most common beginner UA. Figure 3. Illustration of UA control continuum.
Introduction 9 an onboard autopilot that translates the inputs into desired outputs. Stabilized control lends a hand to the operator by maintaining stability of the aircraft without the need for fine control inputs by the operator. In essence, stabilized control significantly reduces the required skill level of the operator, while also allowing the operator to safely control the aircraft. This technology has allowed the VTOL market to greatly expand because low-skilled, inexperience operators can safely operate these aircraft (Blanks 2016). With manual remotely piloted aircraft control, the operator directly controls the aircraft flight path without any assistance. For UA, the control is typically via a handheld console, or controller, that allows the operator to control, using two small joysticks, aircraft pitch, roll, yaw, and throttle. Depending on the aircraft, the operator may be able to control other functions, including flaps, landing gear, and brakes. Most newer consumer UA are smartphone or tablet- capable, with many designs depending on a smartphone for operation. Via the smartphone, the operator can control the aircraft, or in a stabilized semi-automatic fashion, program flight plans, with the UA flying the designated path (Blanks 2016). Part 107 of 14 C.F.R. currently requires visual line of sight with the UA (Figure 4). Large UA are controlled through a ground control station (GCS) that has multiple mon- itors and often two crewâpilot and sensor operator. Through satellite uplink, large UA are regularly launched locally with control then switching over to a GCS located halfway around the world to fly the mission, before control reverts back to the local recovery team prior to landing. In defense contractor missions, a military officer is available to âpull the triggerâ on enemy positions, to prevent a civilian from being tasked with this responsibility. See Figure 5. Launch and Recovery Launching and recovering UA can range from fairly simple to more complex. Launching tech- niques include simple liftoff of VTOL aircraft, hand launch, catapult launch, moving-vehicle launch, or hard-surface takeoff. Recovery techniques include vertical landing, belly landing, net capture, or hard-surface landing. The specific launch and recovery methods will be based on UA platform, manufacturer recommendations, and mission conducted. Operators should follow manufacturer-recommended recovery methods. Figure 4. Visual line of sight (Source: International Civil Aviation Organization 2011).
10 Current Landscape of Unmanned Aircraft Systems at Airports Landscape The UAS landscape is rather dynamic, and although there are many stakeholders involved, this synthesis focuses on four main stakeholders: (a) UAS manufacturers or suppliers, (b) UAS operators, (c) airports, and (d) the regulatory body, such as the FAA. Note that although this synthesis focuses mostly on sUAS, larger UAS are expected to become a major factor at airports as tenants begin conducting commercial operations, such as cargo delivery. UAS Manufacturers There are currently hundreds of UAS manufacturers worldwide, with most offering UAS in the very small or small categories. The industry is actually dominated by a small number of UAS manufacturers. Many of these manufacturers are not based in the United States, potentially creating security concerns for public agencies and others. For example, one Chinese manufacturer accounts for 70% of the commercial unmanned aerial system market, including a dominance in the small unmanned aerial system subsector. Recently, due to concerns around security of the software associated with the platform, the U.S. Army issued a memo to cease use of applications created by the manufacturer (Interagency Task Force 2018, p. 51). In April 2017, President Trump signed an Executive Order directing all agencies of the execu- tive branch to âmaximize, consistent with law, through terms and conditions of Federal financial assistance awards and Federal procurements, the use of goods, products, and materials produced in the United Statesâ (Trump 2017). Additionally, some municipalities in the United States have enacted âBuy Americanâ ordinances. These policies have made it challenging to acquire UAS, depending on the mission and UAS desired. In September 2018, the Department of Defense released Assessing and Strengthening the Manufacturing and Defense Industrial Base and Supply Chain Resiliency of the United States (Interagency Task Force 2018). Within this report, specific challenges being faced by UAS manu- facturers include long product/system development timelines, high development and qualification costs, and produc- tion limitations. In addition, the sector is experiencing a shortage of workers with critical hardware and software design capabilities due to large retirement populations, limited platform knowledge transfer Figure 5. Command-and-control communication links (Source: International Civil Aviation Organization 2011).
Introduction 11 opportunities, and skyrocketing demand for software engineers outstripping supply in multiple product line sectors (Interagency Task Force 2018, p. 65). It is important for airports to be discerning purchasers of UAS, especially in light of these challenges. UAS Operators It seems that new uses of UAS are being discovered daily. UAS are currently being operated by numerous entities and individuals. Consider some of these users: â¢ Federal government operators (e.g., Department of Defense, National Aeronautics and Space Administration, Department of Homeland Security, Department of the Interior, Customs and Border Protection, and Federal Emergency Management Agency); â¢ State government operators (e.g., departments of transportation [DOTs], departments of agriculture, law enforcement agencies, state homeland security agencies, and universities); â¢ Local government operators (local law enforcement, local fire rescue, universities); â¢ Civilian operators (commercial manufacturers, UAS service businesses); and â¢ Recreational operators. Generally, there are two main users of UAS. First, the existing organization that is not neces- sarily aviation related, but is seeking to enhance efficiencies by integrating UAS into their daily operations. This includes real estate companies, electrical service providers, and state DOTs. Second, numerous organizations are categorized as UAS service providers in which their very business depends upon UAS, including UAS manufacturers. According to Matus and Hedblom (2018): UAS technology is revolutionizing aviation at a very intense pace. There are a host of industries seeking to leverage UAS technology, their applications and advance their operations to new levels of efficiency and enhanced productivity (p. 2F1â10). Airports Although some airports own and operate UAS for their own purposes, airport operators also recognize the extensive use of UAS by the general public. This has introduced concerns among airport operators. As explained by the International Civil Aviation Organization (2011, p. 19), âIt is generally recognized that integration of RPA [UAS] into aerodrome operations will prove to be among the greatest challenges.â Specific areas to be considered include â¢ Applicability of aerodrome [airport] signs and markings for RPA; â¢ Integration of RPA with manned aircraft operations on the maneuvering area of an aerodrome; â¢ Issues surrounding the ability of RPA to avoid collisions while maneuvering; â¢ Issues surrounding the ability of RPA to follow air traffic control instructions in the air or on the maneuvering area (e.g., âfollow green Cessna 172â or âcross behind the Air France A320â); â¢ Applicability of instrument approach minima to RPA operations; â¢ Necessity of RPA observers at aerodromes to assist the remote pilot with collision avoidance requirements; â¢ Implications for aerodrome licensing requirements of RPA infrastructure, such as approach aids, ground handling vehicles, landing aids; launch/recovery aids, etc.; â¢ Rescue and firefighting requirements for RPA (and remote pilot station, if applicable); â¢ RPA launch/recovery at sites other than aerodromes; â¢ Integration of RPA with manned aircraft in the vicinity of an aerodrome; and â¢ Aerodrome implications for RPA-specific equipment (e.g., remote pilot stations) (Inter- national Civil Aviation Organization 2011, pp. 20â21).
12 Current Landscape of Unmanned Aircraft Systems at Airports Many airports have created websites that are used to educate the public about UAS and the need to operate UAS safely. For example, the Houston Airport System has created an âUnmanned Aircraft Systems (Drones) Operationâ webpage at https://www.fly2houston.com/biz/about/ UAS-operations. This webpage reminds UAS operators that âSafety is everyoneâs responsibility.â It provides information for commercial UAS operators, public UAS operators, and hobbyists (recreational UAS operators), with links to the B4UFLY app, and websites of the Academy of Model Aeronautics (AMA), the Association for Unmanned Vehicle Systems International (AUVSI), and the FAA. The âAirport Drone Useâ website of the city of Hutchinson, Minnesota, contains a form that allows UAS operators to notify the airport of their intended drone opera- tion within 5 miles of the airport. Form fields include altitude, type of activity, number of UA, description of UA, date of flight, and duration. These websites support safe operations and serve as a useful outreach tool to engage the community of UAS users. A number of airports are also requiring UAS operators to apply for and be granted a UAS per- mit from the airport prior to operating commercially on airport. For example, the Port of Port- land, in addition to having an âUnmanned Aircraft Systems (UAS) Operationsâ website (https:// www.portofportland.com/Programs/drones), has created a permitting process for commercial UAS operators who wish to operate UAS on Port property. Applications must be submitted at least 5 business days in advance of the intended operation and are subject to Port approval. According to the website, âThe Port of Portland prohibits recreational UAS operations on Port properties including aviation, marine, industrial, and environmental properties.â Even with these challenges, airport operators are not only acquiring UAS for their own use (Figures 6 and 7), but also are cooperating with the FAA Low Altitude Authorization and Noti- fication Capability (LAANC) program to enable others to safely operate UAS. Regulatory Body In the United States, the FAA retains responsibility for ensuring the safe use of the National Airspace System (NAS) by both manned and unmanned aircraft. The FAA is âdedicated to ensuring safety requirements are met for integration of unmanned aviation into the NAS, where unmanned aircraft are able to operate safely in the same airspace with manned aircraftâ (FAA 2017a, p. 1). Through 14 C.F.R. Part 107 (Small Unmanned Aircraft Systems) UAS Test Sites, UAS Integration Pilot Program, UA registration, and AC 107-2 (Small Unmanned Aircraft Figure 6. Airport use of UAS at Centennial Airport serving the Denver-Aurora metropolitan area (Photo credit: Deborah Grigsby Smith 2018).
Introduction 13 Systems), the FAA has been quite active in this area. The FAA continues to work toward full integration of UAS into the NAS, working with manufacturers and operators to ensure that this is done safely and efficiently. Additionally, states, municipalities, and agencies and universities throughout the United States are active in this area. Regulations, ordinances, and proclamations are being issued, some of which support safe use of UAS, whereas others discourage the use of UAS. For example, the City of Los Angeles, California, passed an ordinance that, in essence, codified some of 14 C.F.R. Part 107 in consideration of city requirements, including that (a) no person shall operate any model aircraft within the City of Los Angeles and within 5 miles of an airport without the prior express authorization of the airport air traffic control tower and (b) no person shall operate any model aircraft within the City of Los Angeles in a manner that interferes with manned aircraft, and shall always give way to any manned aircraft (Los Angeles Municipal Code 2015). The National League of Cities (NLC) offers a âModel Ordinance for the Promotion of Drone Innova- tion and Accountabilityâ to their members (National League of Cities n.d.). The NLC encour- ages the safe and responsible use of UA. The ordinance that the group proposes is âdesigned to empower innovation while protecting and promoting the health, safety, and welfare of its citizensâ (National League of Cities n.d., p. 1). Within this model ordinance, the NLC recom- mends consideration of the following sections: â¢ Purpose, â¢ Definitions, â¢ Development of rules, â¢ Notice of intended operation, â¢ No reckless operation, and â¢ Penalties (National League of Cities n.d.). The National Conference of State Legislatures (NCSL) maintains an inventory of state laws regarding drone/UAS use. According to the NCSL, âState legislatures across the country are debating if and how UAS technology should be regulated, taking into account the benefits of their use, privacy concerns and their potential economic impact. So far, 41 states have enacted laws addressing UAS and an additional three states have adopted resolutionsâ (National Con- ference of State Legislatures 2018). State laws are categorized by the NCSL in the following categories: â¢ Preemption, â¢ Privacy, â¢ Hobbyists, Figure 7. Airfield inspection by UAS Centennial Airport (Photo credit: Michael Fronapfel 2018).
14 Current Landscape of Unmanned Aircraft Systems at Airports â¢ Insurance, â¢ Commercial use, â¢ Governmental use, â¢ Criminal penalties for misuse, â¢ Hunting and fishing, â¢ Security concerns, and â¢ Studies and task forces (National Conference of State Legislatures 2018). Recent action taken by states includes the following: â¢ Kentucky HB 540 allows commercial airports to prepare unmanned aircraft facility maps and specifies that UAS operators cannot operate, take off, or land in areas designated by an air- portâs map. It also prohibits operation of UAS in a reckless manner that creates a serious risk of physical injury or damage to property. A violation is a class D felony if it causes a significant change of course or a serious disruption to the safe travel of an aircraft. The law specifies that these provisions do not apply to commercial operators in compliance with FAA regulations. â¢ Minnesota SF 550 appropriated $348,000 to assess the use of UAS in natural resource monitoring of moose populations and changes in ecosystems. â¢ South Dakota SB 22 exempts UAS that weigh less than 55 lb from aircraft registration require- ments, and Utah SB 111 exempts UAS from aircraft registration in the state. â¢ North Dakota SCR 4014 supports the development of the UAS industry in the state, con- gratulates the FAA on the first Beyond Visual Line of Sight Certificate of Authorization in the United States, and encourages further cooperation with the FAA to safely integrate UAS into the national airspace. â¢ Utahâs resolution, HCR 21, supports the building of a NASA drone testing facility and Command Control Center in Tooele County, Utah (National Conference of State Legislatures 2018). Summary Heralded as the game-changer for many industries, the unmanned segment of the aviation industry is on a significant growth trajectory. Millions of these systems are in the hands of private citizens, small businesses, and organizations worldwide. Specifically exploring airport, airport contractor, and airport tenant use of UAS is the focus of this synthesis. Only by better understanding current capabilities and UAS missions being completed by these parties can the entire airport industry benefit from this technology. Furthermore, by measuring the impacts, both positive and negative, of UAS operations on airports, the airport industry can quantify the benefitsâwhich will support expanded use of UAS at both large and small and both commercial service and general aviation airports nationwide.