Best Practices for Airport Obstruction Management Guidebook (2019)

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7 Key Insights The safety of flight and welfare of the general public is contingent on preventing airspace hazards. Navigable airspace may be affected by a variety of objects and land uses, including vegetation, structures, terrain, and traverseways (roadways, driveways, highways, parking lots, railways, and navigable waterways). The responsibility and authority to enforce airport and airspace protection through land use controls lies with local authorities; this creates a disconnection between the evaluation and mitigation of airspace impacts. State zoning and permitting regulations vary widely, from no requirements to stringent require- ments, and criteria to plan, zone, and coordinate uses within the state that may affect the navigable airspace and state aviation resources. State transportation agencies or aeronautics divisions generally have the most up-to-date information on state and local requirements and resources to protect airports and airspace from encroachment by tall structures. Key Definitions 14 Code of Federal Regulations (CFR) Part 77: Safe, Efficient Use and Preservation of the Navigable Airspace (FAR Part 77): Federal regulations that contain the requirements and criteria for the determination of obstructions to air navigation and navigational and communication facilities and the evaluation of their effect on the safe and efficient use of navigable airspace and air navigation facilities and equipment. Airport elevation: The elevation of the highest point of an airport’s usable landing area. Airport imaginary surfaces: A set of geometric surfaces overlying and surrounding the air- port, which visually depict the airport and airspace obstruction evaluation criteria contained in FAR Part 77 and other airspace regulations and sets of criteria and are used to establish whether a structure, object of natural growth, or terrain constitutes an airspace obstruction. Airport layout plan (ALP): A set of drawings that provide a graphic representation of the sponsor’s long-term development plan for an airport, including property boundaries, exist- ing and proposed airport facilities and structures, and the location of existing and proposed nonaeronautical areas. C H A P T E R 2 Airport Obstruction Management and the Regulatory Environment

8 Best Practices for Airport Obstruction Management Guidebook Airport reference point: The center point of an airport, located at the geometric center of all usable runways. Airspace hazard: An airspace obstruction that has been studied and determined to have a substantial adverse effect, affecting a significant volume of aeronautical activity. Airspace obstruction: An object that exceeds the obstruction standards identified in FAR Part 77.23 that upon FAA evaluation is determined to be required to be properly marked, lighted, and identified on aeronautical publications so that it can be recognized by aircraft navigating through the airspace. Approach minimums: A height above ground or altitude at which the pilot must discontinue the approach and execute a missed approach procedure if a required visual reference to the runway system is not established. Circling approach area: The area in which an aircraft circles to land under visual conditions after completing an instrument approach. Displaced threshold: A runway threshold located at a point on the runway, other than the beginning of the runway, not available for aircraft landing but available for aircraft taxiing and taking off. FAA AC 120-91: Airport Obstacle Analysis: Describes acceptable methods and guidelines for developing takeoff and initial climb-out airport obstacle analyses and in-flight procedures for commercial air carriers and on-demand operators. FAA AC 150/5300-13A: Airport Design: Contains standards and recommendations for the geometric layout and engineering design of runways, taxiways, aprons, and other facilities at civil airports. FAA Engineering Brief 91: Management of Vegetation in the Airport Environment: Details the practices of collecting vegetation obstruction data, submitting the data to the FAA, and man- aging the vegetation impacting navigable airspace, as a supplemental means of compliance with standards outlined in Advisory Circular 150/5300-18B and Advisory Circular 150/5300-13A. FAA Joint Order (JO) 7400.2L: Procedures for Handling Airspace Matters: Prescribes policy, criteria, guidelines, and procedures applicable to the various FAA Lines of Business and services by establishing procedures for the handling of airspace matters. FAA Order 8260.3D: United States Standard for Terminal Instrument Procedures (TERPS): Prescribes the standardized methods for designing and evaluating instrument flight procedures in the United States and its territories. FAA Standard Operating Procedure (SOP) 9.00: FAA Aeronautical Study, Coordination and Evaluation: Applicable to FAA airports staff, establishing the criteria for the manage- ment of airport obstruction data in the Obstruction Evaluation/Airport Airspace Analysis system, coordination and evaluation of Obstruction Evaluation/Airport Airspace Analysis determinations, coordination of changes to ALPs and supporting documents, and coordi- nation of determinations related to activation, construction, alteration, or deactivation of public-use airports. Federal airway: A defined corridor within the National Airspace System that connects specific locations to one another and can be grouped into Victor airways, Jet airways, and area naviga- tion routes. Initial approach segment: A segment of an instrument approach procedure that begins at an initial approach fix and generally terminates at the intermediate approach segment, providing for the initial alignment of aircraft with the approach course.

Airport Obstruction Management and the Regulatory Environment 9 Instrument approach procedure (IAP): A series of predetermined maneuvers for the orderly transition of an aircraft under instrument flight conditions from the beginning of the initial approach to a landing or a point from which a landing may be visually made. International Civil Aviation Organization (ICAO) Annex 6: Operation of Aircraft: The subset of ICAO standards for the operation of aircraft engaged in international air transport, to ensure the highest levels of safety and efficiency. National Airspace System (NAS): The airspace, navigation facilities, and airports of the United States along with their associated information, services, rules, regulations, policies, pro- cedures, personnel, and equipment. Nonprecision approach procedure: A standard instrument approach procedure with mini- mums not lower than 3/4 mile and/or 250-foot ceiling, for which at least horizontal guidance is provided with a ground-based navigational aid or global positioning system. A nonprecision approach utilizing a global positioning system may also provide vertical guidance, depending on the approach and equipage of the aircraft. Object: Any element of natural growth, terrain, man-made structure, or clearance zone representing passing vehicles on a traverseway that vertically protrudes into the airspace. Obligated airport: An airport that has received federal grants under the Airport Improvement Program or prior federal airport grant program or operates on property that was conveyed to the airport under a federal surplus property program. Obstacle: Any object that does or would penetrate an obstacle clearance surface or other clearance requirements for a specific flight procedure. An obstacle is known as a controlling obstacle when it is used as the limiting factor for vertical clearance for the flight procedure. Obstruction: See airspace obstruction. Obstruction Evaluation/Airport Airspace Analysis (OE/AAA): FAA’s electronic resource for submission and tracking of notices required under FAR Part 77.17 by the public and the FAA internal review coordination of the notices. Precision instrument procedure: A standard instrument procedure for an aircraft to approach an airport, in which vertical and horizontal guidance is provided to the pilot using an instrument landing system, military precision approach radar, or a global positioning system, with visibility of 3/4 mile or less or a ceiling less than 250 feet. Private-use airport: An airport available for use only with prior approval of the airport owner or operator. Public-use airport: An airport, publicly or privately owned, that is open for aviation use by the public without prior permission. Substantial adverse aeronautical effect: An impact on navigable airspace that necessitates a change to an instrument approach procedure, an approach minimum, an element of an airport or a navigational aid or a change in a vectoring altitude, so as to meet minimum procedure or facility design standards. The impact has to affect at least one daily operation (or a similar cumu- lative annual number of operations) to be considered substantial. 2.1 Understanding Objects, Obstructions, Obstacles, and Hazards Aviation is an important part of our nation’s transportation system and supports economic activity. According to FAA data, United States’ air carriers accommodated more than 830 million enplanements in 2016. Additionally, more than 78.7 million tons of cargo were carried by air.

10 Best Practices for Airport Obstruction Management Guidebook Those numbers do not take into consideration the transportation of the public or cargo via GA aircraft. Compared to 2015 data, these numbers represent a 3.6 percent increase in passenger traffic and a 4.5 percent increase in cargo vol- ume, or nearly 30 million additional enplanements and 3.4 million additional tons, respectively. While enplanements and cargo movements by air continue to grow to record levels from year to year, the economic recovery has spurred pressures on develop- ment and construction in urbanized areas and beyond. While the FAA and the users of the NAS have taken steps to relieve congestion and increase system capac- ity through the modernization of the infrastructure and air traffic control systems, system capacity continues to be constrained, resulting in air carrier delays and lost revenue. Constraint on system capacity is further exacerbated by introducing objects into the navigable airspace that require changes or constraints in existing or planned operations. Using several sets of regulations and rules (discussed further in this chapter), the FAA evaluates the presence of objects in navigable airspace in order to determine their impact on NAS safety and efficiency. The FAA regulations define standards and so-called “imaginary surfaces,” which exist to evaluate and ensure safe clear- ance of all obstacles by aircraft in flight. The FAA works to ensure that objects in navigable airspace do not negatively affect aviation safety, but the only tool avail- able to the FAA to do this is to modify flight procedures. These modifications can potentially affect airport capacity or NAS efficiency. Thus, the presence of objects in navigable airspace can have direct and indirect local and regional economic consequences. Working to prevent substantial adverse effects from the presence of objects in navigable airspace is in the best interest of all aviation and nonaviation stakeholders. It is critical to understand the key differences in terminology that define how the FAA treats various objects affecting airspace. An object is any element of natural growth, terrain, man-made structure, or clear- ance zone representing passing vehicles on a traverseway. Independently, an object can be an obstruction, obstacle, or hazard. While “element of natural growth” covers trees and brush, the classification of man-made structures as objects is all-inclusive. Man-made structures include everything from runway edge lights, fences, light poles, and construction equipment to broadcast towers, skyscrapers, and all appurtenances thereto. Additionally, traverseways have additional heights added to their surface elevations to account for vehicle heights. The FAA must be notified of all objects—whether permanent or temporary— that exceed the standards contained in FAR Part 77 Subpart C. For an object to be categorized as an obstruction, it must be evaluated by the FAA and determined to be required to be properly marked, lighted, and identified on aeronautical charts. Multiple cri- teria are considered to determine obstructions to air navigation, as outlined in FAR Part 77.23, including exceeding basic heights, clearance for terminal or en route procedures, and airport imaginary surfaces defined in FAR Parts 77.25, 77.28, or 77.29. While FAR Part 77 and its requirements will be discussed in further detail in the follow- ing sections, it is critical to understand that FAR Part 77 includes the criteria that specify not only what constitutes an obstruction, but also when to notify the FAA of any proposed struc- ture or alterations to one. At times, this creates confusion among those who are charged with OBJECTS, OBSTRUCTIONS, OBSTACLES, AND HAZARDS It can be difficult to discern the differences in FAA nomenclature for impacts on navigable airspace. It is critical to understand the meaning of each of the terms used in obstruction management discussions and regulations. As defined in ACRP Report 38: An object is any element of natural growth, terrain, man-made structure, or clearance zone representing passing vehicles on a traverseway that vertically protrudes into the airspace. Independently, an object can be an obstruction, obstacle or hazard. An obstruction to air navigation is any object that upon FAA evaluation is determined to be required to be properly marked, lighted, and identified on aeronautical publications so that it can be recognized by aircraft navigating through the airspace. Obstructions are subject to further aeronautical study to assess hazard status. An obstacle is any object that does or would penetrate an OCS or other specific clearance required, such as for a flight procedure. An obstacle is known as a “controlling obstacle” when a flight procedure is designed around that obstacle as the limiting factor to the detriment of airport operations and efficiency. An example of a hazard would be an antenna tower that results in the loss of an airport instrument approach or a building that requires runway shortening or threshold displacement. A hazard to air navigation is an obstruction or other adverse object that FAA aeronautical study concludes would have a substantial adverse effect to a significant volume of aeronautical operations.

Airport Obstruction Management and the Regulatory Environment 11 implementing the airspace protection provisions at the local level, because the notice require- ments can be more restrictive than the obstruction standards. Not all items that require notifi- cation are not obstructions. In addition, not all obstructions are a hazard to air navigation, as described below. Airspace obstacles are objects that exceed FAR Part 77 obstruction standards or other specific clearance requirements but do not result in a substantial adverse effect to air navigation. Such objects may affect one or more imaginary surfaces, flight procedure design criteria, or airport design standards, but measures can be taken to ensure that the safety of flight and airport efficiency is maintained. In the event that a particular object becomes the key obstacle, which serves as the obstruction baseline for a particular airport or runway, it is known as the controlling obstacle and is utilized as the object that determines how the flight procedures it affects are designed. Hazards to air navigation are obstructions that have been studied by the FAA, and the agency has determined that constructing or maintaining that object would result in a substantial adverse effect, which affects a significant volume of aeronautical activity. To constitute a hazard, the obstruc- tion must exceed the FAR Part 77 or other obstacle clearance standards and require the FAA to mitigate its impact by altering the airport design (e.g., runway length), instrument approaches or departures, or operation of navigational equipment, and that change must affect a substantial number of operations at that airport (usually at least 365 operations per year). Only the FAA has the authority to issue airspace hazard determinations following the agency’s internal review process and external coordination with the process stakeholders. More detail on that obstruction analysis process is available in Section 2.2. An FAA review is required to determine whether an object required to file under FAR Part 77.17 is an obstruction and whether the obstruction is an obstacle or a hazard for air navigation. Simply exceeding a certain set of FAA standards does not automatically result in an object being a hazard to air navigation. However, a finding by the FAA that an object does not constitute a hazard does not automatically indicate that the impact of the proposed object should be found to be acceptable by the decision-making authorities. While the FAA’s OE/AAA process examines the impacts of proposed or existing obstructions on navigable airspace and can result in the FAA’s issuance of hazard determinations for struc- tures and vegetation, the protection of airport airspace from encroachment is contingent on local government authorities. The FAA does not have, nor does it exercise, any local enforce- ment authority. While the FAA will work to ensure aviation safety through all the available means, such as the cancellation of an approach, an increase in minimums, a runway threshold displacement, or procedure limitations, only the local government zoning entities possess the means to enforce height or use limitations within their jurisdictional limits. Airspace protection by the federal government is not wholly possible without coordinated and vested collaboration among the FAA, airport sponsors, airport users, and local communities. 2.2 Navigable Airspace Regulations Title 49 U.S. Code § 40103 establishes the United States government’s exclusive sovereignty over the U.S. navigable airspace. The same law directs the FAA administrator to develop and implement policies for the use of the airspace, which is carried out within the parameters of a number of federal regulations discussed in this section. That authority is further affirmed by 49 U.S. Code § 44718: Structures Interfering with Air Commerce, which requires adequate public notice for a proposal that may affect safety in air commerce, the efficiency and preserva- tion of the navigable airspace and airport traffic capacity, and the interests of national security. While a number of recent court cases have attempted to challenge those provisions of the law

12 Best Practices for Airport Obstruction Management Guidebook at altitudes below 500 feet, the FAA continues to analyze and issue determinations regarding the impacts that structures and vegetation have on the navigable airspace. The purpose of this process is to protect the safety of the public in the air and on the ground, as well as the opera- tional safety of the nation’s aviation facilities and the public investment therein. 2.3 FAA Airspace Regulations and Criteria There are three key documents that implement the authorization to protect the navigable airspace: • FAR Part 77 • FAA AC 150/5300-13A: Airport Design • FAA Order 8260.3D: The United States Standard for Terminal Instrument Procedures (TERPS) A fourth, FAA AC 120-91: Airport Obstacle Analysis, while not regulatory for airports, is required for air carriers. Table 2.1 summarizes the key airspace regulatory documents. This section describes the guidance documents and their application to airport obstruction management. In addition, the FAA can issue additional guidance on airport design in the form of engineering briefs, which is addressed in this section. 14 CFR Part 77: Safe, Efficient Use and Preservation of the Navigable Airspace (FAR Part 77) FAR Part 77 forms the foundation of the airspace obstruction notification and evaluation criteria. It is used by the FAA and many state agencies charged with obstruction evaluation as the initial set of criteria to establish the potential impact of an object on navigable airspace. The purpose of the notification required by FAR Part 77 is to serve as the basis for • Evaluating the effect of the construction or alternative on operating procedures • Determining the potential hazardous effect of the proposed construction on air navigation • Identifying mitigation measures to enhance safe air navigation • Charting of new objects FAR Part 77 establishes • Requirements and criteria to provide notice to the FAA of certain types of proposed construc- tion or the alteration of existing structures • Standards used to determine obstructions to air navigation and navigational and communica- tion facilities Criteria Role FAR Part 77 Primary airspace obstruction notification and evaluation criteria that guide the obstruction notification and obstruction evaluation processes at the federal level. FAA AC 150/5300-13A Federal criteria containing standards for the design and development of safe and efficient airports. FAA Order 8260.3D (TERPS) Federal regulations containing the standards for the design of instrument flight procedures (IFPs). FAA AC 120-91 and ICAO Annex 6 Federal and international regulations establishing the requirement for U.S. and international air carriers to analyze aircraft performance, enabling an aircraft to safely clear obstacles when an engine fails during departure. Table 2.1. Summary of federal regulatory requirements and criteria.

Airport Obstruction Management and the Regulatory Environment 13 • A process for aeronautical studies of obstructions to air navigation or navigational facilities to determine the effect on the safe and efficient use of navigable airspace, air navigation facilities, or equipment • A process to petition the FAA for discretionary review of determinations, revisions, and exten- sions of determinations FAR Part 77 Notification It is important for tall structure proponents to understand that the FAR Part 77 notification requirements are more stringent than the obstruction evaluation criteria, to provide the FAA an opportunity for the development to be reviewed. All on-airport development must be reviewed. For off-airport development, FAR Part 77 contains criteria that specify which objects require a notice to be filed with the FAA for their pro- posed construction or alteration. Those criteria are in §77.9 and specify the following proposals that require the proponent to notify the FAA: • Any construction or alteration that is more than 200 feet above ground level (AGL) at its site • Any construction or alteration that exceeds one of the following horizontal slopes: – 100-to-1 slope for a horizontal distance of 20,000 feet from the nearest point of the nearest runway of any public-use and military airport – 50-to-1 for a horizontal distance of 10,000 feet from the nearest point of the nearest runway of each public-use and military airport, when its longest runway does not exceed 3,200 feet in length, excluding heliports – 25-to-1 for a horizontal distance of 5,000 feet from the nearest point of the nearest landing and takeoff area of each heliport • Any highway, railroad, or other traverseway for mobile objects, of a height which, when adjusted for vehicle heights (see Section 2.1) would exceed the standards listed above • Any construction or alteration on any of the public-use or military airports and heliports or those operated by a federal agency or the Department of Defense • Any proposal that is deemed by the FAA to require an evaluation, as requested by the agency For proponents who are not familiar with the proper application of the §77.9 criteria, the FAA has a Notice Criteria Tool available on the FAA’s OE/AAA website (see Figure 2.1). The tool Source: FAA Notice Criteria Tool. Available at https://oeaaa.faa.gov/oeaaa/external/gisTools/gisAction.jsp?action=showNoNoticeRequiredToolForm Figure 2.1. Notice Criteria Tool.

14 Best Practices for Airport Obstruction Management Guidebook analyzes coordinate and elevation information provided by the proponent and issues an instant response on whether Form 7460-1 should be filed with the FAA. Proponents who are required to file a notice with the FAA pursuant to §77.9 should do so by submitting to the FAA a complete FAA Form 7460-1: Notice of Proposed Construction or Alteration and all the supporting documents. The FAA requests electronic submissions, unless it is not feasible, in which case the form is available to download for paper submission. Electronic submittal allows for tracking of the submitted cases within the FAA review framework. Form 7460-1 must be submitted at least 45 days before the start of the proposed construction or alteration activity. The requirement for a 45-day advance notice can be waived in the event that immediate construction or alteration is required due to an emergency involving essential public services or hazards to public health or public safety. In that event, the proponent may provide notice to the FAA by any available and expeditious means, such as a telephone call to the nearest FAA flight service station (800-9292-7433). Following the emergency notification, the proponent must file a completed FAA Form 7460-1 with the FAA within 5 days of the initial notice. For structures subject to Federal Communications Commission licensing, the notice to the FAA must be submitted on or before the date that the application is filed with the Federal Communications Commission. It is critical to note that any willful and knowing failure to comply with the FAR Part 77 notification requirements constitutes a violation of federal law and is subject to a civil penalty of $1,000 per day, pursuant to 49 U.S.C., Section 46301(a), until the notice is received by the FAA. For any parties that erect or maintain an object that affects flight safety, the civil penalty constitutes only one of the potential liabilities. In the event that the object in question results in an aviation mishap, the party responsible for following the requirements of FAR Part 77 may be open to additional litigation and damages. FAR Part 77 Evaluation Obstruction analysis is accomplished through the FAA OE/AAA process, with a goal of exam- ining objects that exceed the FAR Part 77 notification criteria, establishing whether the objects exceed any of the obstruction clearance surfaces prescribed by FAR Part 77 and determining whether the objects have a substantial adverse effect on a significant volume of aeronautical activity. The FAA’s Air Traffic Organization uses the expertise of its FAA obstruction evaluation specialists and technicians to determine the nature and magnitude of airspace impacts by natu- ral or man-made objects on navigable airspace. In addition to FAR Part 77 and this guidebook, ACRP Report 38 contains valuable information and resources related to FAR Part 77 and the FAA evaluation process. The criteria that serve as the initial means of identifying any potential adverse impacts on navigable airspace and the potential presence or absence of an adverse aeronautical effect are defined by §77.17. Any existing or future object, including mobile objects, would constitute an obstruction to air navigation if it were greater in height than any of the following heights or surfaces: • A height of 499 feet AGL at its site. • A height that is 200 feet AGL or 200 feet above the established airport elevation (whichever is higher) for an object located within 3 nautical miles of the established airport reference point of an airport where the longest runway is more than 3,200 feet long. That height increases proportionally by 100 feet for each additional nautical mile from the airport up to a maximum of 499 feet. • A height within a terminal obstacle clearance area, including an initial approach segment, a departure area, and a circling approach area, which would result in the vertical distance

Airport Obstruction Management and the Regulatory Environment 15 between any point on the object and an established minimum instrument flight altitude within that area or segment to be less than the required obstacle clearance. The areas subject to this criterion extend many miles from the airport in all directions, but vary by airport based on runway configuration, existing topography, volume of traffic, and other factors. Certain areas are required to be clear to allow aircraft to gradually descend and be sequenced for arrival or to safely depart. Objects, weather conditions, and traffic separation criteria must be accounted for. • A height within an en route obstacle clearance area, including turn and termination areas of a federal airway or approved off-airway route, that would increase the minimum obstacle clearance altitude. • The surface of a takeoff and landing area of an airport or any imaginary surface established under §77.19, 77.21 or 77.23. Additionally, as shown in Figure 2.2, traverseways (including parking lots and even private driveways) must be evaluated for aeronautical impact by the FAA due to the occasional passage of mobile objects over those traverseways. The traverseways are evaluated for impact on the §77.17 criteria by assigning the following imaginary heights to their surfaces to account for the passage of mobile objects: • 17 feet for an interstate highway • 15 feet for any other public roadway • 10 feet, or the height of the highest mobile object that would normally traverse the road (whichever is greater), for a private road Source: FAA Order JO 7400.2L, Figure 5-2-4 Figure 2.2. Vehicle height to add for traverseway.

16 Best Practices for Airport Obstruction Management Guidebook • 23 feet for a railroad • An amount equal to the height of the highest mobile object that would normally traverse a waterway or any other traverseway not previously mentioned Exceeding any of the obstruction evaluation criteria creates a presumption that a particular object may result in a hazard to air navigation. However, FAR Part 77 does not contain the hazard criteria, and merely exceeding the obstruction evaluation criteria does not automati- cally result in a final hazard determination. Also, FAR Part 77 surfaces alone do not constitute the only obstruction identification surfaces that affect airports and their users. To establish the impact of the proposal, further analysis is conducted by the FAA. The analysis also evaluates the options for mitigating the potential impact of the object on air navigation while maintaining safety of flight. The analysis initiated by the FAA for any object that may be a potential hazard to air navi- gation involves the various FAA Lines of Business (LOBs) reviewing the information submit- ted by the proponent. The FAA may also send information about the potential obstruction to other potentially affected parties, such as nearby airports or their users. During the analysis of the proposals, the FAA LOBs reference rules, regulations, and criteria that define the airport parameters within their areas of responsibility. The two primary sets of regulations include the criteria for airport design and standards for the design of TERPS, both of which are discussed below. FAA AC 150/5300-13A: Airport Design FAA AC 150/5300-13A contains the criteria pertinent to the design of airports. While the document is informational and does not have regulatory authority in its own right, compliance with the circular’s criteria constitutes a means to meet the condition of a “manner approved by the administrator,” to fulfill federal grant assurances for any federally obligated airports, which are airports that have accepted federal financial resources for airport development. Related to obstruction management, FAA AC 150/5300-13A addresses • The identification of appropriate design standards based on the size of aircraft using the airport • Runway design, including runway end siting requirements, surface grading, object clearing and obstacle clearance standards, and basics of approach and departure protection Chapter 3 of AC 150/5300-13A contains dimensional specifications for required runway widths; dimensions for areas that should be free from objects or obstacles; separation criteria between runways, taxiways, and aprons; and specifics on allowed objects within the various parts surrounding the runways. These dimensional standards are driven primarily by the airport’s overall aircraft design group, as well as the design code for individual runways. The two sets of criteria are based on the airport’s “critical aircraft”—the most demanding aircraft or group of aircraft that will conduct at least 500 annual operations at the airport per year. The design aircraft approach speed and wingspan or tail height serve as the standards for determining the applicability of the airport design criteria and the specific dimensions of each surface. While the AC 150/5300-13A does not directly address or identify obstruction hazards, it does define the threshold siting surfaces (TSSs) that identify where the runway thresholds can be located based on obstacles that are on and off airport. Conversely, these criteria can be utilized to verify whether a particular object or a group thereof will result in an impact on the airport and its runways. The TSS criteria are specific to the size of aircraft and approach minimums. These criteria also include the definition of a departure surface, which is discussed in further detail in Section 3.4.

Airport Obstruction Management and the Regulatory Environment 17 FAA Order 8260.3D: The United States Standard for TERPS To provide all-weather access to airports, IAPs are designed by the FAA. Pilots follow IAPs using the electronic signal from navigation aids to fly without reference to the ground between airports. The design standards for these IAPs are contained in FAA Order 8260.3D, commonly referred to as TERPS. FAA Order 8260.3D is an extensive set of standards that specify the criteria for designing and evaluating instrument flight procedures (IFPs). These criteria are used by the FAA during the obstruction evaluation process to establish any effect a proposal may have on existing or planned instrument procedures. The criteria in TERPS establish required obstacle clearances above objects and terrain in the airport’s vicinity. Meeting the clearance requirements, coupled with the airport’s infrastructure, enables an approach to be designed and minimums established for IAPs to an airport. Using FAR Part 77 notification criteria to identify potential objects with the potential to impact navigable airspace and coordinating the proposal with the FAA through the OE/AAA process enables an agency to evaluate the proposal for airport design standards and TERPS without the proponent needing all the criteria. While it is not necessary to know the intricacies of TERPS, a basic understanding of TERPS applicability to a particular airport is valuable. TERPS criteria impacts can result in a finding of substantial adverse impact, leading the FAA to issue a determination of hazard to air naviga- tion. Section 3.4 provides additional information on the application of TERPS design standards to airports. FAA Engineering Brief 91: Management of Vegetation in the Airport Environment Unlike the previously discussed regulations, FAA engineering briefs serve a role of clarifica- tion and guidance related to other FAA criteria or regulatory documents. FAA Engineering Brief 91 details how airport owners and operators collect, submit, and manage the data describ- ing vegetation on or near the airport that affects or has the potential to affect the safe and efficient use of the airport. TERPS covers the following topics and criteria: • Administrative and regulatory elements of instrument procedure development • General criteria for the development of standard terminal arrival procedures; feeder routes; initial, intermediate, and final approach segments of IAPs; circling and missed approaches; and terminal area fixes • Criteria for the establishment of takeoff and landing minimums • Criteria for the development of nonprecision approaches (based on various navigational aids) • Criteria for the development of precision approaches and precision approach obstacle assessment • Radar approach criteria • Criteria for the development of helicopter instrument approaches • Departure procedure and en route obstacle clearance criteria • Holding pattern design • Design of simultaneous approach operations

18 Best Practices for Airport Obstruction Management Guidebook Specifically, the brief explains how to comply with FAA AC 150/5300-13A and 150/5300-18: General Guidance and Specifications for Submission of Aeronautical Surveys to NGS: Field Data Collection and Geographic Information System (GIS) Standards. The brief also identifies how to limit the effects of existing airport airspace objects and prevent future airport object penetra- tions of airport surfaces by proactively collecting, reporting, and managing data regarding the vegetation on and/or surrounding the airport. Engineering Brief 91 addresses some of the issues and topics related to vegetation obstruction management, such as the following: • Regulatory and environmental considerations of natural resource impacts as a result of veg- etation management • Vegetation removal or trimming alternatives, including vegetation maintenance programs • Collection, classification, submission, and management of vegetation data • Step-by-step instructions for submitting vegetation data to the FAA Engineering Brief 91 is a concise and useful supplement to information contained in the advisory ACs, especially on vegetation management. It presents ample guidance and clarification on FAA documents for airports dealing with vegetation concerns in obstruction management. Air Carrier Regulations—FAA AC 120-91 and ICAO Annex 6 FAA AC 120-91 and ICAO Annex 6 address the regulatory requirements of aircraft operating under 14 CFR Parts 121 (scheduled air carriers) and 135 (charter, on-demand air carriers) associated with obstacle analysis for OEI procedure development. While these standards are not directly for an airport, they can impact airport users, which in turn can have an effect on operation at the airport. FAA AC 120-91: Airport Obstacle Analysis OEI takeoff is an irregular operation stemming from an engine shutdown or stop on a multiengine aircraft during takeoff, which would result in a lower climb rate. FAA AC 120-91 establishes acceptable methods and guidelines for developing takeoff and initial climb-out obstacle clearance analyses and in-fight procedures to meet regulatory requirements. It does so by providing air carriers with the following: • Information on how to determine safe clearance of obstacles for the aircraft flightpath • Guidance on the consideration of all factors that may result in the aircraft diverting from the intended flightpath • Criteria to assist the air carrier performance engineers in the development of takeoff procedures FAA AC 120-91 covers: • Departure procedure considerations • Obstacle data considerations and periodic review • Methods of and considerations in obstacle analysis: area analysis and flight track analysis • Course guidance corrections for analysis of intended versus actual flightpaths • Departure turn analysis • OEI missed approach and rejected landing analysis considerations • Distribution of operating procedure data to flight crews “Obstacle accountability area” (or “splay”) is a term that refers to the lateral distance on each side of the intended flight track for which objects are presumed to be flown over. Objects outside of the “splay” are presumed to be cleared laterally and do not factor into climb gradient require- ments to vertically clear them. TERPS criteria on departure obstacle clearance are based on normal aircraft operations. The OEI criteria exist to consider abnormal operations. When establishing OEI procedures, air carriers are expected to use the best and most accurate obstacle data available. These data come from sources other than the FAA.

Airport Obstruction Management and the Regulatory Environment 19 The air carrier requirements to ensure the safety of flight and an adequate separation from all known obstacles in the event of an engine failure can affect an airport’s ability to meet the efficiency and market demands of those carriers and to provide service at the airport. If an object penetrates the OEI off the end of a runway, to provide a clear OEI, the air carrier may be required to consider part of the runway unavailable. This effectively shortens the available runway length and could result in offloading passengers, fuel, or revenue cargo. While the OEI surface is not an airport requirement, it is important for airports to work in partnership with their air carriers to protect the surface. ICAO Annex 6: Operation of Aircraft ICAO Annex 6, Chapter 5, focuses on aircraft performance limitations. Similar to FAA AC 120-91, ICAO Annex 6 requires the air carrier to collect and maintain data to comply with takeoff, en route, and landing obstacle clearance requirements for safe operations. While this require- ment applies to foreign flag commercial air carriers, any U.S. airport that accepts foreign flag carriers must consider the implications of this requirement. Any impacts by existing or proposed objects on the ability of such carriers to comply with ICAO Annex 6 requirements could impact their ability to operate at the airport. While ICAO Annex 6 is a requirement for foreign flag carriers, some of the U.S. passenger and cargo air carriers utilize the ICAO Annex 6 OEI splay for obstacle analysis and departure plan- ning purposes. The ICAO Annex 6 OEI splay is larger than the AC 120-91 OEI splay, as shown in Figure 2.3. Source: Planning Technology Inc., 2018 Figure 2.3. FAA AC 120-91 and ICAO Annex 6 OEI splay comparison.

20 Best Practices for Airport Obstruction Management Guidebook A comparison of the two criteria shows that the ICAO splay covers a larger area; therefore, ICAO Annex 6 criteria are more likely to require an air carrier to account for obstacles that are farther from the extended runway centerline than FAA AC 120-91 criteria. The implications of this are two-fold: • The controlling objects (critical obstacles) for each of the splays for the same runway end may be different, which may result in different clear slopes for the FAA and ICAO splays. • Protecting both criteria is important to account for potential industry changes and existing conditions outside of the narrower FAA splay. Even if all the air carriers flying from the airport use and are required to clear obstacles within the narrower FAA splay, some of them may use the ICAO splay as a “buffer zone” or “reality check.” For example, if a large building is outside the FAA splay but within the ICAO splay, an air carrier may impose a maximum crosswind restriction on departures, so that the aircraft is not blown outside the narrower splay during an emergency. Alternatively, a vis- ibility requirement could be imposed so that the pilot can see and avoid the obstacle. Either way, any restrictions have the potential to decrease runway availability and utilization, thereby reducing the capacity of the airport. Thus, it is important for an airport to understand not only what criteria the air carriers are required to apply, but any additional criteria they may take into consideration. 2.4 Understanding the FAA Obstruction Evaluation Process The OE/AAA process is initiated when a proponent submits a Form 7460-1, typically through the OE/AAA website. The FAA review of a submitted Form 7460-1 is an inter- disciplinary process. The lead LOB within the FAA is different for a review of off-airport proposed development than it is for on-airport proposed development. The FAA LOBs and other agencies that can be involved in a review of proposed development include the following: • FAA Airports: This business area is responsible for all programs related to airport safety and inspections, as well as standards for airport design, construction, and operation. Additionally, this division is involved with national environmental, airport planning, and grant assurance compliance matters. • FAA Air Traffic: This business area is responsible for keeping air traffic moving safely throughout the skies. • FAA Technical Operations: This business area is responsible for managing air navigation ser- vices and infrastructure, as well as policy and standards development for airspace procedures and equipment. • FAA Spectrum Engineering (Frequency Management) Office: This office is charged with managing and protecting frequency spectrum resources for civil aviation users. • FAA Flight Standards Service: This business area is responsible for setting and enforcing standards for the certification and oversight of airmen, air operators, and air agencies. • FAA Flight Procedure Standards Branch: This branch is responsible for establishing and implementing IFP design standards, policy, and criteria. Additionally, the branch is respon- sible for developing obstacle clearance standards and accommodating new and emerging technologies for the NAS. • U.S. Department of Defense. • U.S. Department of Homeland Security.

Airport Obstruction Management and the Regulatory Environment 21 Initiation and Coordination of the OE/AAA Process for Off-Airport Structures Following the OE/AAA process initiation, the overall performance and coordination of aeronautical studies for proposals located off airport are conducted by the FAA Air Traffic Organization’s Obstruction Evaluation Group (OEG). After a proposal is submitted in the OE/AAA system, the form is initially received by an OEG technician, who will verify the submittal for completeness and accuracy. The minimum require- ments for a Form 7460-1 submittal include the following: • Completed Form 7460-1 • A letter from a survey company certifying the accuracy of the longitude and latitude coordi- nates and site elevation • A scaled drawing of a proposed structure that depicts site orientation, coordinates for highest point(s) and/or each corner as applicable, dimensions, and construction materials or the size and configuration of wires for transmission lines • An 8.5-by-11-inch copy of the applicable 7.5-minute U.S. Geological Survey quadrangle map showing the precise location of the proposed structure • For transmitting stations and antennas, the maximum effective radiated power, center of radiation, frequencies, and antenna type(s) If additional information is required, the technician will contact the proponent and request the missing information or additional clarification. If no additional information is required to proceed with the study, the technician will assign an aeronautical study number to the proposal, which advances the study to an OEG specialist. An aeronautical study number is automati- cally assigned if the proposal is electronically submitted. The information becomes available for review by other FAA LOBs and non-FAA agency representatives. All LOBs are required to participate in the review of the aeronautical study. There are a few exceptions, such as if an aeronautical study involves an evaluation of a side-mounted antenna on a structure previously studied by the agency. In such a case, only the affected divisions (such as Frequency Management) will be involved in the review. Additionally, FAA Air Traffic Orga- nization staff may request that other divisions or agencies that are not normally involved in the limited review weigh in on a particular proposal or part thereof, which may affect their division’s responsibilities. Initiation and Coordination of the OE/AAA Process for On-Airport Structures The primary FAA responsibility for overseeing the on-airport OE/AAA process lies with FAA Airports, with the local Airports district office or region—if there is no district office—taking the lead. While off-airport proposals are required to undergo a review only if they exceed FAR Part 77 notification criteria, all on-airport proposals that involve construction or are other- wise potentially affecting the airport’s imaginary surfaces (e.g., new landscaping or trees or growing vegetation) are required to undergo FAA airport airspace analysis. This evaluation requirement is regardless of whether or not the FAA is funding the proposed development. Airport sponsors or on-airport proponents are required to notify the FAA of the proposed construction or alteration by filing Form 7460-1 through OE/AAA. After receiving the on-airport proposal, the FAA Airports staff will verify the information sub- mitted for accuracy and completeness, such as verifying the submitted coordinate and elevation data to confirm that the proposal’s anticipated location matches those coordinates. Additionally, the Airports staff will verify the consistency of the proposal with the approved ALP, and if the

22 Best Practices for Airport Obstruction Management Guidebook proposal is found to be inconsistent with the ALP but a favorable airspace determination can be issued, Airports staff will advise the airport sponsor of the need to update the ALP for consistency. To assist in a consistent OE/AAA review across all FAA regions, the FAA developed FAA Stan- dard Operating Procedure (SOP) 9.00: FAA Aeronautical Study, Coordination and Evaluation. SOP 9.00 guides the review and maintenance of on-airport obstruction data, the obstruction evaluation process related to reviews of ALPs, and the receipt and evaluation of on-airport notices related to proposed construction or alteration. The FAA processes the on-airport obstruction evaluation studies as nonrulemaking airport studies and evaluates the proposals for effects on the safety, utility, and efficiency of the airport, as well as for consistency with the approved ALP. Because of the roles and responsibilities FAA Airports plays within the FAA organizational structure, some of the FAA Airports district offices focus the on-airport airspace analysis on con- sistency with the airport design standards in FAA AC 150/5300-13A. Before the FAA Airports group issues a determination, the staff is required to coordinate and circulate the proposal to other FAA LOBs potentially affected by the proposal. Those offices are given 45 working days to provide comments on a proposal or waive comment. It is recommended that upon receipt of a final nonrulemaking airport determination from the FAA Airports staff, the proponent should check whether an OEG specialist provided comments. If not, the proponent should request clarification or comment on the proposal from the OEG specialist responsible for the area where the airport is located. This helps avoid any potential conflict between the proposed project and criteria and standards that fall within the OEG’s area of responsibility. The contact information for the OEG specialist responsible for each geographic region is on the OE/AAA site. Although the approval of on-airport projects is one of the areas of responsibility for FAA Airports staff [via Airports district offices], airspace determinations issued by FAA Airports district office staff alone do not constitute approval for the development or project to proceed. The project is still subject to any required environmental review, as discussed in Section 7.4. Evaluating the Aeronautical Effect of On- and Off-Airport Proposals As a part of its OE/AAA review, the FAA considers the following: • The preservation of navigable airspace and its integrity • Protection of air navigation facilities from electromagnetic and physical encroachments that would degrade the facility’s operation While the agency attempts to accommodate various uses affecting the airspace, airspace protection and integrity take priority. The OE/AAA review primarily focuses on the effect the proposal would have on the following: • Existing or proposed public-use and U.S. Department of Defense airports or facilities • Existing or proposed IFPs, visual flight procedures, and minimum flight altitudes • Existing or proposed navigation, communication, radar, or air traffic control facilities related to frequency, electromagnetic, or line-of-sight interference • Overall airport capacity as a result of the cumulative effect of the proposal with other existing and proposed obstructions During the process of evaluating impacts to airspace, the FAA seeks to answer two key questions: • Will the proposal have an adverse effect on navigable airspace? • Will the effect of this proposal affect a significant volume of aeronautical activity? SUBSTANTIAL ADVERSE EFFECT A substantial adverse effect finding is the primary reason for FAA determinations of hazard, unless the impact is mitigated. The finding requires three key elements to be present: • Impact on Part 77 imaginary surfaces or navigational or air traffic control facilities • Resultant required change to an existing or planned air navigational procedure or derogation of airport capacity/efficiency • Impact on a significant volume of activity— from one operation per week to one or more operations per day

Airport Obstruction Management and the Regulatory Environment 23 To decide whether the proposal will have an adverse effect on air navigation, the FAA deter- mines whether the structure would exceed FAR Part 77 standards or would have physical or electromagnetic effects on navigation aids. If either is the case, the FAA determines whether the proposal will • Require a change to an existing or planned instrument flight rules (IFR) minimum flight altitude, a published or special instrument procedure, or an IFR departure procedure for a public-use airport • Require a visual flight rule (VFR) operation to change its regular flight course or altitude. This does not apply to VFR military training route operations, operations conducted under Part 137: Agricultural Aircraft Operations, or operations conducted under a waiver or exemption to the CFR • Restrict the clear view of runways, helipads, taxiways, or traffic patterns from the airport traffic control tower cab • Derogate airport capacity/efficiency • Affect future VFR and/or IFR operations, as indicated by plans on file • Affect the usable length of an existing or planned runway Generally, any regular and continuing activity that will be altered or affected by the proposal (such as one or more airport takeoffs or landings per day) is considered substantial. Nonethe- less, altering or affecting an activity that occurs on average once per week can be considered significant, if the procedure or minimum altitude used serves a primary airport operational role under certain conditions. If the proposal is determined to have an adverse effect and to affect a significant volume of activity, it is found to have a substantial adverse effect on air navigation. In the event of a substantial adverse effect determination, the FAA can issue a determination of hazard to air navigation, underscoring that the proposal—at its proposed height and location—will not be able to be accommodated without negatively affecting the safety and efficiency of the NAS. If the volume of aeronautical activity subject to the proposal’s impact is not significant, the FAA will be able to adjust affected operations or procedures (if any) and will issue a determination of no hazard to air navigation. While the FAA does not generally evaluate airspace impacts on private-use facili- ties, the agency analyzes proposals that may affect a private-use airport with at least one FAA-approved IAP. Appendix C in ACRP Report 38 includes a detailed and thorough explanation of the FAA OE/AAA process, from the submittal of Form 7460-1 to the issuance of determinations and petitions for discretionary review (which constitutes a de facto appeal of an FAA finding). After Construction The FAA obstruction evaluation process must occur prior to a structure being constructed and therefore should be initiated at least 45 days prior to the start of construction. If the FAA issues a favorable determination to a filed Form 7460-1 and the proposed construction pro- ceeds, after the structure construction is complete, the FAA requests that the proponent submit a supplemental notice (Form 7460-2). These data for the new object are verified for accuracy by the agency and are used to update the Digital Obstacle File (DOF) database. It is critical to note that although the FAA OE/AAA process is thorough and evaluates the pro- posal’s potential impact on airport and airspace efficiency, it does not fully consider the impacts of proposed structures on OEI surfaces of airports having air carrier service.

24 Best Practices for Airport Obstruction Management Guidebook While the FAA evaluates airport efficiency to determine whether the adverse impact affects a significant volume of activity, it does so from the standpoint of the number of operations affected. The evaluation does not assess the volume of activity from the standpoint of types of operations impacted. Therefore, if a proposal impacts an OEI surface and the impacted air car- rier is required to adjust its passenger or cargo carrying capacity to meet the requirements of FAR Parts 121 or 135 or ICAO Annex 6 on obstacle clearance, it will not be considered by the FAA in the issuance of a final airspace determination. Creating airport-specific OEI surfaces and protecting them through local airport protection zoning mechanisms extends the protections to such surfaces (further discussed in Section 3.5). 2.5 State Regulatory Environment States have the sovereign authority to adopt, administer, and impose legislative mandates on communities that aim to protect the elements of the state airport system and the public investment in that system. Airport protection zoning is generally defined as a set of state or local government rules and regulations that aim to protect the navigable airspace over and airports within specific jurisdictions from encroachment and impacts by tall structures and/or vegetation. “Airspace Protection and Land Use Zoning: A Nationwide Review of State Statutes,” prepared for the Minnesota Department of Transportation, indicated that 43 states have some type of legislation that addresses the need to protect navigable airspace at the local level. Generally, state airspace protection zoning legislation falls into one of two categories: 1. Legislation authorizing local airspace protection zoning, in which local governments are enabled to administer measures to protect the airports and airspace. 2. Legislation requiring local airspace protection zoning, in which local governments are required to adopt airport protection zoning measures, which may be a condition of state airport improvement grant funding support. When the FAA issued AC 150/5190-4A: A Model Zoning Ordinance to Limit Height of Objects Around Airports, many states used it to establish regulations. At present, only Alaska, Georgia, Hawaii, Idaho, Kentucky, Massachusetts, and West Virginia do not authorize or require local government airport protection zoning, as shown in Table 2.2. However, as discussed in the Minnesota Department of Transportation report cited above, many of those states address airspace protection at the state level, generally through a state tall structure permitting process. Additionally, a number of U.S. states have developed resources (guidebooks, toolkits, etc.) focusing on airspace protection that vary in technical complexity and scope. Some of the resources are very comprehensive, for instance the California Airport Land Use Planning Handbook and the Iowa Airport Land Use Guidebook, prepared for the Iowa Department of Transportation, Office Authorized Required Neither Alabama, Arizona, Arkansas, California, Colorado, Delaware, Illinois, Indiana, Kansas, Louisiana, Maine, Maryland, Mississippi, Missouri, Nevada, New York, North Carolina, North Dakota, Utah, Vermont, Wyoming Connecticut, Florida, Iowa, Michigan, Minnesota, Montana, Nebraska, New Hampshire, New Jersey, New Mexico, Ohio, Oklahoma, Oregon, Pennsylvania, Rhode Island, South Carolina, South Dakota, Tennessee, Texas, Virginia, Washington, Wisconsin Alaska, Georgia, Hawaii, Idaho, Kentucky, Massachusetts, West Virginia Source: Transportation Research Synthesis 1401: Airspace Protection and Land Use Zoning: A Nationwide Review of State Statutes Table 2.2. State airport and airspace protection regulations.

Airport Obstruction Management and the Regulatory Environment 25 of Aviation. They provide extensive resources and tools for use by airport sponsors and local governments seeking to implement airport protection measures. These resources are included in the guidebook bibliography. State resources dedicated to mitigation strategies and conflict resolution or consensus building related to airspace protection are generally lacking. While the discussion and evaluation of individual state requirements is beyond the scope of this guidebook, it is important to note the significance of state requirements on the overall process of obstruction management. State regulatory involvement may result in the following impacts on an airport obstruction management program: • The state tall structure permitting process may preempt local obstruction management authority if it is less restrictive than state law • State law may require the coordination of airport obstruction management strategies with state land use planning, environmental, or transportation agencies • Obstruction management plans may be required to be coordinated with or incorporated into local or state comprehensive plans • State regulations may require interlocal coordination of airport obstruction management plans or strategies with surrounding jurisdictions In addition to federal regulations, some states may have environmental requirements that affect the obstruction management process. Those state-specific elements may need to be addressed in addition to the airspace obstruction requirements. They may involve elements such as protection measures for certain vegetation or wildlife species, limitations on felling and/or harvesting of trees, and protection of sensitive state water resources during the implementation of obstruction management. Sponsors are encouraged to verify state airport obstruction management requirements pertinent to their airport and coordinate the implemen- tation of obstruction management with the state aeronautics, transportation, environmental protection, and land use planning agencies early in the process.