Understanding Airspace, Objects, and Their Effects on Airports (2010)

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Introduction Appendix A highlights the primary purpose and function of each referenced document and explains the specific application and relevance to Airspace, Objects, and Their Effects on Air- ports. Although these criteria documents contain substantial overlap and cross-referencing, they can generally be grouped into three major categories, based on their primary function: (1) air- space protection; (2) airport design; and (3) flight procedure design. These categories consider airspace interference caused by physical objects. A fourth category of criteria documents address electro-magnetic interference, or NAVAID and surveillance protection. The criteria documents annotated herein include: Airspace Protection ✈ Federal Aviation Regulations (FAR) Part 77, Objects Affecting Navigable Airspace ✈ FAA Order JO 7400.2, Procedures for Handling Airspace Matters ✈ FAA Advisory Circular (AC) 70/7460-1, Obstruction Marking and Lighting ✈ FAA AC 70/7460-2, Proposed Construction or Alteration of Objects that May Affect the Navigable Airspace ✈ FAA Form 7460-1, Notice of Proposed Construction or Alteration ✈ FAA Form 7460-2, Notice of Actual Construction ✈ The OE/AAA External User Website ✈ FAA, Airport Obstructions Standards Committee (AOSC), Decision Documents ✈ FAA, AC 150/5190 4A, A Model Zoning Ordinance to Limit Height of Objects Around Airports ✈ FAA AC 150/5070-6B, Airport Master Plans Airport Design ✈ FAA AC 150/5300-13, Airport Design ✈ FAA AC 150/5300-18, General Guidance and Specifications for Submission of Aeronautical Sur- veys to NGS: Field Data Collection and Geographic Information System (GIS) Standards ✈ FAA AC 150/5390-2A, Heliport Design ✈ FAA AC 150/5395-1, Seaplane Bases ✈ FAA Order 6750, Siting Criteria for Instrument Landing Systems ✈ FAR Part 139, Certification of Airports ✈ FAR Part 157, Notice of Construction, Alteration, Activation, and Deactivation of Airports Flight Procedure Design ✈ FAA Order 8260.3B, The United States Standard for Terminal Instrument Procedures (TERPS) ✈ TERPS Derivative Orders (8260 Series) 41 A P P E N D I X A The Purpose, Function, and Application of Criteria

✈ TERPS Instruction Letters (TILs) ✈ FAA AC 90-80B, Approval of Offshore Standard Approach Procedures, Airborne Radar Approaches, and Helicopter En Route Decent Areas ✈ FAR Part 25, Airworthiness Standards: Transport Category Airplanes ✈ FAA AC 120-91, Airport Obstacle Analysis ✈ FAA AC 120-29A, Criteria for the Approval of Category I and II Weather Minima for Approach ✈ FAA AC 120-28D, Criteria for the Approval of Category III Weather Minima for Takeoff, Land- ing, and Rollout ✈ FAR Part 121, Operating Requirements: Domestic, Flag, and Supplemental Operations ✈ FAA Handbook, FAA-H-8261-1A, Instrument Procedures Handbook ✈ FAA Air Traffic Publication, Aeronautical Information Manual ✈ FAA, National Aeronautical Charting Office (NACO) Website Electromagnetic Interference ✈ FAA Order 6310.6, Primary/Secondary Terminal Radar Siting Handbook ✈ FAA Order 6340.15, Primary/Secondary En Route Radar Siting Handbook ✈ FAA Order 6820.10, VOR, VOR/DME and VORTAC Siting Criteria ✈NITA Technical Report TR-08-454, Assessment of the Effects of Wind Turbines on Air Traffic Control Radars Airspace Protection Criteria As outlined here, airspace protection criteria are set forth in the following documents:  U.S. Code of Federal Regulations (CFR), Title 14—Federal Aviation Regulations (FAR) Part 77, Objects Affecting Navigable Airspace  FAA Order JO 7400.2, Procedures for Handling Airspace Matters  FAA Advisory Circular 70/7460-1, Obstruction Marking and Lighting  FAA Advisory Circular 70/7460-2, Proposed Construction or Alteration of Objects that May Affect the Navigable Airspace  FAA Form 7460-1, Notice of Proposed Construction or Alteration  FAA Form 7460-2, Notice of Actual Construction  FAA OE/AAA Website, http://oeaaa.faa.gov  FAA, Airport Obstruction Standards Committee (AOSC), Decision Documents  FAA Advisory Circular 150/5190-4A, A Model Zoning Ordinance to Limit Height of Objects Around Airports  FAA Advisory Circular 150/5070-6B, Airport Master Plans Federal Aviation Regulations (FAR) Part 77, Objects Affecting Navigable Airspace Latest amendment 2004. Notice of Proposed Rulemaking (NPRM) changes June 2006, pending. http://www.access.gpo.gov/nara/cfr/waisidx_04/14cfr77_04.html Purpose  Establishes the Federal law for the protection of airspace  Sets forth the requirements for Notification to the Administrator of certain proposed construction or alteration  Establishes the standards for classifying an object as an “obstruction to air navigation”  Provides for aeronautical studies of obstructions to air navigation, to determine the effect of proposed construction or alteration on air navigation  Provides for the establishment of antenna farms 42 Understanding Airspace, Objects, and Their Effects on Airports

Function  Subpart A—Provides general terms that apply to objects affecting navigable airspace.  Subpart B—Specifies notification requirements for sponsors proposing to build tall structure or structures near airports. Specifies standards to identify construction or alter- ations requiring notice, construction or alternation not requiring notice, forms required for filing notice, and FAA’s role in acknowledging notice.  Subpart C—Specifies the standards for determining obstructions to air navigation. These standards apply to the use of navigable airspace by aircraft and to existing navigation facilities. Provides protection of airspace for civil and military airports and heliports, and for flight procedures.  Subpart D—Specifies the aeronautical study process by the FAA.  Subpart E—Specifies the Rules of Practice for hearings conducted by FAA.  Subpart F—Specifies the establishment of antenna farm areas. Application of Criteria FAR Part 77 serves as Federal law as it pertains to objects that affect navigable airspace. The criteria apply both to sponsors proposing construction and to the FAA. Sponsors Sponsors of proposed construction or alteration in the vicinity of airports are required to provide notification to the FAA as detailed in FAR §77.13 by filing FAA Form 7460-1, Notice of Proposed Construction, and responding to FAA’s inquires that may be posed throughout the aeronautical study process. Notification is required for the following types of structures: §77.13(a)(1) A height more than 200 feet above ground level (AGL) at its site (Figure A.1); §77.13(a)(2) Within 20,000 feet of a runway more than 3,200 feet in length, and exceeding a 100:1 slope imaginary surface (i.e., a surface rising 1 foot vertically for every 100 feet horizontally) from the nearest point of the nearest runway. (Different standards apply with proximity to airports with run- ways no greater than 3,200 feet in length, and heliports) (Figure A.1); §77.13(a)(3) Roadways, railroads, and waterways are evaluated based on heights above surface provid- ing for vehicles; by specified amounts or by the height of the highest mobile object normally traversing the transportation corridor; The Purpose, Function, and Application of Criteria 43 Figure A.1. Profile view of two types of FAR Part 77.13 notification requirements.

§77.13(a)(4) When requested by the FAA, any construction or alteration that would be in an instrument approach area and may exceed FAR Part 77 obstruction standards; or, §77.13(a)(5) Any construction or alteration on any public-use or military airport. FAA The FAA is responsible for acknowledging the receipt of the notice of proposed construc- tion, and conducting an aeronautical study based on the obstruction standards presented in FAR §77.23. An existing object is, and a future object would be, an obstruction to air navigation if it is of greater height than any of the following heights or surfaces: §77.23(a)(1)—A height of 500 feet AGL. §77.23(a)(2)—A height that is 200 feet AGL or above the established airport elevation, whichever is higher, within 3 nautical miles of the established airport reference point, with its longest runway more than 3,200 feet in actual length. That height increases in the proportion of 100 feet for each additional nautical mile from the airport up to a maximum of 500 feet. See Figure A.2. §77.23(a)(3)—A height within a terminal obstacle clearance area, including initial approach segment, a departure area, and a circling approach, which would result in the vertical distance between any point on the object and an established minimum instrument flight altitude within that area to be less than the required obstacle clearance. 44 Understanding Airspace, Objects, and Their Effects on Airports Figure A.2. Obstruction standards per §77.23(a)(2).

§77.23(a)(4)—A height within an en route obstacle clearance area, including turn and terminal areas, of a Federal airway or approved off-airway route, that would increase the minimum obstacle clearance altitude. §77.23(a)(5)—The surface of a takeoff and landing area of an airport or any imaginary surface estab- lished in §77.25, §77.28, and §77.29. The imaginary surfaces referenced in §77.23(a)(5) are defined geometrically in §77.25 (civil), §77.28 (military), and §77.29 (heliports). The most familiar type to U.S. civil airport opera- tors are the “civil airport imaginary surfaces”, illustrated in Figure A.3. The dimensions of many of the surface components are dependent on runway and approach types. Therefore, the runway and approach types must be established first, as follows: A utility runway is a runway that is constructed and intended to be used by propeller driven aircraft of no more than 12,500 pounds maximum gross weight. While the FAA does not set a specific length to determine a utility runway, in general they are no more than 3,500 feet in length, and may not necessarily be paved or lighted. A visual runway is a runway that is intended solely for the operation of aircraft using visual approach procedures. Visual runways are only used when “VFR” conditions exist, that is, when cloud ceilings are at least 1,000 feet AGL and visibility is at least 3 statute miles (under certain circumstances visibility may be as low as 1 statute mile). These runways are identified by their basic runway markings (runway designator and centerlines). A non-precision instrument runway is one that may be accessed for approach using an FAA published “nonprecision instrument approach procedure.” Nonprecision instrument approach procedures are those procedures where the use of a nonprecision instrument NAVAID is used as the basis for the approach. Nonprecision instrument procedures include those that reference VORs, NDBs, and GPS waypoints. Nonprecision instrument procedures offer only lateral guid- ance to the runway. These runways may be accessed under less than VFR conditions, typically conditions where the cloud ceilings are as low as 700 feet AGL and visibility is greater than 1⁄2 mile. These runways are identified by “nonprecision” runway markings (runway designator, center- line, and threshold markings). A precision instrument runway is a runway that has an existing instrument approach proce- dure that utilizes an Instrument Landing System (ILS) or a Precision Approach Radar (PAR). These procedures provide both lateral and vertical guidance to a particular runway, and thus allow aircraft to approach the runway during conditions of minimal visibility. These runways are identified by “precision” runway markings (runway designator, centerline, threshold markings, and touchdown zone markings). The civil airport imaginary surfaces are then constructed as follows: Primary surface. A surface longitudinally centered on a runway. When the runway has a specially prepared hard surface, the primary surface extends 200 feet beyond each end of that runway. But when the runway has no specially prepared hard surface or planned hard surface, the primary surface ends at each end of that runway. The elevation of any point on the primary surface is the same as the elevation of the nearest point on the runway centerline. The width of a primary surface is 250 feet for utility runways having only visual approaches. 500 feet for utility runways having nonprecision instrument approaches. For other than utility runways the width is: (i) 500 feet for visual runways having only visual approaches. The Purpose, Function, and Application of Criteria 45

46 Understanding Airspace, Objects, and Their Effects on Airports Figure A.3. FAR Part 77, §77.25 civil airport imaginary surfaces.

(ii) 500 feet for nonprecision instrument runways having visibility minimums greater than three-fourths statute mile. (iii) 1,000 feet for a nonprecision instrument runway having a nonprecision instrument approach with visibility minimums as low as three-fourths of a statute mile, and for pre- cision instrument runways. The width of the primary surface of a runway will be that width prescribed in this section for the most precise approach existing or planned for either end of that runway. Horizontal surface. A horizontal plane 150 feet above the established airport elevation, the perimeter of which is constructed by swinging arcs of specified radii from the center of each end of the primary surface of each runway of each airport and connecting the adjacent arcs by lines tangent to those arcs. The radius of each arc is: (1) 5,000 feet for all runways designated as utility or visual; (2) 10,000 feet for all other runways. Conical surface. A surface extending outward and upward from the periphery of the horizon- tal surface at a slope of 20 to 1 for a horizontal distance of 4,000 feet. Approach surface. A surface longitudinally centered on the extended runway centerline and extending outward and upward from each end of the primary surface. An approach surface is applied to each end of each runway based upon the type of approach available or planned for that runway end. The inner edge of the approach surface is the same width as the primary surface and it expands uniformly to a width of: (i) 1,250 feet for that end of a utility runway with only visual approaches; (ii) 1,500 feet for that end of a runway other than a utility runway with only visual approaches; (iii) 2,000 feet for that end of a utility runway with a nonprecision instrument approach; (iv) 3,500 feet for that end of a nonprecision instrument runway other than utility, having visibility minimums greater than three-fourths of a statute mile; (v) 4,000 feet for that end of a nonprecision instrument runway, other than utility, hav- ing a nonprecision instrument approach with visibility minimums as low as three- fourths statute mile; and (vi) 16,000 feet for precision instrument runways. The approach surface extends for a horizontal distance of: (i) 5,000 feet at a slope of 20 to 1 for all utility and visual runways; (ii) 10,000 feet at a slope of 34 to 1 for all nonprecision instrument runways other than util- ity; and, (iii) 10,000 feet at a slope of 50 to 1 with an additional 40,000 feet at a slope of 40 to 1 for all precision instrument runways. The outer width of an approach surface to an end of a runway will be that width prescribed in this subsection for the most precise approach existing or planned for that runway end. Transitional surface. These surfaces extend outward and upward at right angles to the run- way centerline and the runway centerline extended at a slope of 7 to 1 from the sides of the primary surface and from the sides of the approach surfaces up to the elevation of the hori- The Purpose, Function, and Application of Criteria 47

zontal or conical surface. Transitional surfaces for those portions of the precision approach surface which project through and beyond the limits of the conical surface, extend a distance of 5,000 feet measured horizontally from the edge of the approach surface and at right angles to the runway centerline. As previously mentioned, in addition to notification criteria and obstruction criteria, FAR Part 77 provides for aeronautical studies. The aeronautical studies are conducted by the FAA Regional Air Traffic Division Manager or his designee within the Obstruction Evaluation Ser- vice (OES). The aeronautical study includes analysis of the effects of the proposed construc- tion on air navigation facilities and the safe efficient use of navigable airspace. Refer to Appendix C for a detailed description of the FAA OE/AAA process. FAA Order JO 7400.2G—Procedures for Handling Airspace Matters Latest amendment April 2008 http://www.faa.gov/airports_airtraffic/air_traffic/publications/atpubs/AIR/ Purpose Joint Order (JO) 7400.2G specifies policy, criteria, guidelines, and procedures for use by all personnel in the joint administration applicable to the System Operation Services, System Operation Airspace, and Airman’s Informational Manual (AIM), Technical Operations, ATC Spectrum Engineering Services, the Office of Airport Planning and Programming, the Office of Airport Safety and Standards, Technical Operations Aviation System Standards, and the Flight Standards Service. This Order also applies to all regional service area, and field organi- zation offices involved in the rulemaking and non-rulemaking actions associated with air- space allocation, obstruction evaluation, obstruction marking and lighting, airport airspace analysis, and the management of air navigation aids. The document incorporates several orders, notices, and directives to provide Federal govern- ment (all agencies listed previously) personnel procedures for the management of all airspace programs. It serves as a single reference document for all airspace matters in the NAS, how- ever it is important to note that additional criteria and procedures may exist that supplement these procedures. Function The primary function of this order is to provide procedures for agency handling of Airspace Management, Objects Affecting Navigable Airspace, Airport Airspace Analysis, Special Use Airspace and other miscellaneous airspace procedures. Application of Criteria The criteria contained in Order 7400.2 are directly applicable to the current airspace structure as it exists today and as it will exist in the future. Part 2, Objects Affecting Navigable Airspace, is directly applicable to objects affecting navigable airspace (as it is titled). The guidance pro- vides the basis for the FAA OE/AAA program, and defines the role of FAA, procedures to be followed, obstacle evaluation automation, training requirements, aeronautical study struc- ture, process and considerations, verification of proposed case, the identification of aeronau- tical effect of proposed construction, determinations, post determination actions, and the discretionary review process. Order 7400.2, Chapter 6—Aeronautical Studies, specifies the steps in the OE/AAA process, which is described in more detail in Chapter 5 of this report. The FAA’s Determination of Hazard is based on the judgment that a proposed structure would cause a “substantial adverse 48 Understanding Airspace, Objects, and Their Effects on Airports

effect” to a “significant volume of traffic”. Section 3 of Chapter 6 describes the criteria for determining adverse effect, significant adverse effect, and significant volume of activity. Besides functioning as an interpretive manual for application of criteria specified in other doc- uments (FAR Part 77, TERPS) to airspace matters, Order 7400.2 specifies criteria not found else- where for protection of VFR airspace (Figure A.4). Subsection 6-3-8 specifies criteria for protection of VFR routes, VFR traffic pattern airspace, and helicopter operations. Subsections 6-3-13 and 6-3-14 discuss shielding criteria, the criteria that apply to structures whose aeronau- tical effects can be shown to be no worse than those caused by existing precedent structures. FAA personnel associated with OE/AAA or conducting airspace assessments follow these cri- teria. These criteria are transparent and provide the sponsor of proposed construction insight to the process to be followed for the evaluation of any Notice of Proposed Construction case. FAA Advisory Circular 70/7460-1, Obstruction Marking and Lighting Latest amendment February 2007 https://oeaaa.faa.gov/oeaaa/external/content/AC70_7460_1K.pdf Purpose The primary purpose of FAA AC 70/7460-1 is to provide guidance on marking and lighting for structures that exceed obstruction standards. The intent of marking and lighting is to make structures visible to pilots during the day or night for collision avoidance. Function The function of the criteria is to provide marking and lighting guidance to sponsors whose structures exceed 200 feet AGL or any obstruction standards as defined in §77.23. The guidance specifically details marking patterns, colors, and schemes for various types of structures and addresses obstruction light requirements (color and intensity) and vari- The Purpose, Function, and Application of Criteria 49 Figure A.4. Visual flight rules adverse effect per FAA Order 7400.2, 6-3-8(d).

ous lighting configurations for structures of varying heights. The criteria also include guid- ance for sponsors who wish to voluntarily mark or light the structure, even if not required (Figure A.5). Application of Criteria In many OE/AAA cases where a proposed structure exceeds obstruction standards, issuance of a DNH is contingent on the proposed construction being properly marked and lighted. These criteria are provided to sponsors so that they may comply with marking and lighting requirements determined by FAA. Additionally, obstruction marking and lighting are often an insurance coverage requirement. Any structure exceeding 200 feet above ground level or any other FAR 77 obstruction stan- dard must be marked and/or lighted. Marking and lighting of a structure allows pilots to see and avoid the obstacle to ensure the safety to air navigation. The guidance varies depending on structure height, shielding, terrain features, weather patterns, geographic location, and in the case of wind or antenna farms, the number of structures and overall layout (see Figure A.5). FAA Advisory Circular 70/7460-2, Proposed Construction or Alteration of Objects that May Affect the Navigable Airspace Latest amendment March 2000, currently cancelled. http://rgl.faa.gov/REGULATORY_AND_GUIDANCE_LIBRARY/RGADVISORYCIRCULAR. NSF/0/22990146db0931f186256c2a00721867/$FILE/ac70-7460-2K.pdf Purpose The purpose of these criteria is to provide simplified, concise guidance about the OE/AAA process to sponsors proposing to erect or alter an object that may affect navigable airspace, fil- ing 7460-1 notices, and describes the FAA’s OE/AAA process, including determinations and discretionary reviews. 50 Understanding Airspace, Objects, and Their Effects on Airports Illustration of lighting criteria from AC70/7460-1 Figure A.5. Illustration of lighting criteria.

Function The information provides a general audience with details and notice requirements as identi- fied in FAR Part 77, and provides reference to documents for marking and lighting, airport design, lighting equipment, and notice forms 7460-1 and 7460-2. Also included is FAA con- tact information for assistance, identification of the FAA role, and petition guidance. Application of Criteria These criteria are specific to sponsors who are proposing construction of structures that may affect navigable airspace, largely reflecting the criteria in FAR Part 77. Sponsors may use this document as guidance to ensure the proposed construction meets FAA requirements. FAA Form 7460-1, Notice of Proposed Construction http://oeaaa.faa.gov/oeaaa/external/content/7460-1.pdf Purpose Form 7460-1 provides the formal means for a sponsor to provide notice of a proposed con- struction or alternation project to FAA as detailed in FAR Part 77. The form is designed to col- lect the information necessary for the FAA to evaluate the effect of proposed construction or alteration on navigable airspace. Function Form 7460-1 serves as the means for a sponsor to provide the data necessary for FAA to initi- ate an aeronautical study. Application of Criteria Form 7460-1 is to be completed and submitted by sponsors (or their representative) of any proposed construction or alteration project that trigger the FAA reporting requirements as detailed in FAR Part 77, AC 70/7460-2, and JO Order 7400.2G. The notification form serves to start the FAA OE/AAA process. Sponsors can file a paper form by mail or file online at the FAA OE/AAA website. In addition to restating the notification height criteria described in FAR Part 77.13, the form and accompanying instructions (paper or website) contain criteria for timing of submission, accuracy standards of geographic coordinates, and other filing details. FAA Form 7460-2, Notice of Actual Construction http://oeaaa.faa.gov/oeaaa/external/content/7460-2.pdf Purpose Form 7460-2 provides the formal means for a sponsor to provide notice of actual construc- tion to the FAA, as detailed in FAR Part 77. The form is designed to collect the information necessary to monitor and catalogue proposed construction projects for which the FAA has issued a DNH. Function Form 7460-2 serves as means for a sponsor to provide all the required data necessary for FAA to monitor the proposed construction project. Form 7460-2, Part I notifies FAA when con- struction has begun. Part II notifies FAA when the structure has reached its maximum height. The Purpose, Function, and Application of Criteria 51

Application of Criteria Form 7460-2 is to be completed and submitted by sponsors as detailed in FAR Part 77, AC 70/7460-2, and JO Order 7400.2G. This notification form serves as the final phase of the FAA OE/AAA process. The form and accompanying instructions (paper or website) contain crite- ria for timing of submissions, accuracy standards of actual surveyed geographic coordinates, verification of marking and lighting installation, and other filing details. FAA OE/AAA Website Established 2004, regularly updated with improved functions http://oeaaa.faa.gov Purpose The OE/AAA website is a user interactive system allowing for the electronic submittal of Notice of Proposed Construction forms for on- and off-airport construction. It also provides back- ground and context information that users may find useful, and allows subscribers to specify certain geographic boundaries within which they would be automatically notified when OE/AAA cases are circularized under Public Notice and/or determined. This automated system was developed in the 2004 timeframe in order to automate and streamline what had previously been an all-paper process; to reduce time and workload for users and the FAA; and to make the process more transparent. Function The public OE/AAA webpage is designed to provide a convenient means for sponsors to sub- mit and monitor all OE cases, public circularization of OE cases, and a historical archive of determined cases. The public OE/AAA system also sends and receives information from the FAA’s internal-only OE/AAA system. Application The OE/AAA website is located on the internet at http://oeaaa.faa.gov. It provides users with a means to file 7460-1 and 7460-2 forms and receive determinations electronically through an automated process. It contains abundant FAA reference information including policy, procedures, criteria, forms, contact information, and tools for determining reporting requirements, and potential radar impacts. It also contains a searchable, historical database of determined cases, and various tools for sponsors of construction. Anyone may create a user account on this system. Sponsors may create a user account allowing them the ability to create, verify, submit, and manage multiple 7460-1 cases at any given time. Airport owners and municipalities may create a user account and set preferences to receive automatic notification of proposed, circularized, and determined cases in the vicinity of their air- port. The authors of this ACRP research strongly encourage airport managers to do so. FAA, Airport Obstruction Standards Committee, Decision Documents Established 2003 http://www.faa.gov/about/office_org/headquarters_offices/arc/programs/aosc/ The Airport Obstruction Standards Committee (AOSC) was established as a harmonization group for FAA obstruction criteria. The AOSC is charged with development of a transition strategy to guide the application of obstruction standards for airport and operations where no standards currently existed or were applied or where there was confusion or ambiguity regarding application of standards. 52 Understanding Airspace, Objects, and Their Effects on Airports

The AOSC also serves as an entity promoting the transformation of outdated, inconsistent obsta- cle standards and to establish new evolving standards that balance operational safety, efficiency, and economic benefit. As of March 2009, the AOSC has published seven decision documents. Purpose The purpose of the decision documents is to provide additional or updated guidance for obsta- cle protection as it pertains to specific subjects: the Precision Obstruction Free Area (POFA), which was re-designated the Precision Obstacle Free Zone (POFZ) in a subsequent issue of AC 150/5300-13; the effects of Obstacle Free Zone (OFZ) clearance areas on taxiway separation; application of the TERPS 40:1 departure surface; siting criteria for perimeter end around taxi- ways; the effect of airport traffic control towers greater than 300 feet AGL; clarification of obsta- cle survey requirements; the transition process for TERPS Paragraph 251 (visual segment of an instrument approach) covering nighttime operations; analysis of obstacle/airspace/safety rela- tionship pertaining to the Collision Risk Model; measures for compliance with obstruction stan- dards at non air carrier airports; and improved FAA headquarters guidance to assure integrated participation of all lines of FAA business during the construction process. Function These decision documents serve as updated guidance for airports, airport developers, engi- neers, OE/AAA evaluators and the general public. They provide clear decisions on matters of contention or ambiguity. Application of Criteria These decision documents are directly applicable to areas they cover. To date six documents have been published pertaining to POFA: 40:1 departure surface obstructions and evalua- tions; Atlanta Runway 8R-26L end-around taxiway; runway/parallel taxiway separation stan- dards; airport Air Traffic Control Tower interim siting guidance; Dallas/Fort Worth end around taxi system; and national departure case standard for end around taxiway. These criteria are applicable to specific cases. Some of the criteria have been incorporated into FAA Orders and ACs referenced in OE/AAA determinations, and it is likely that ultimately all of these criteria will be incorporated in the future. For example, Decision Document #02b regarding application of the TERPS 40:1 departure surface is occasionally referenced in OE/AAA determinations (see Figure A.6). FAA Advisory Circular 150/5190-4A, A Model Zoning Ordinance to Limit Height of Objects Around Airports Latest amendment December 1987 http://www.faa.gov/airports_airtraffic/airports/resources/advisory_circulars/media/150- 5190-4A/150_5190_4A.PDF Purpose The primary purpose of this advisory circular is to provide a model zoning ordinance to be used as a guide for state and/or local planning agencies to protect airspace and control the height of objects around airports. Function The model zoning guidance provided is predicated on FAR Part 77 and other established airport zoning standard recommendations. It provides various zones required to prevent the creation or establishment of objects that would interfere with the operation of various types of airports. The Purpose, Function, and Application of Criteria 53

Application of Criteria This advisory circular is directly applicable to airport owners and all types of municipal sover- eign bodies. The model zoning includes textual examples of zoning that can be used as the basis of establishing an ordinance. The guide serves to establish an initial set of height limitations around the airport for existing and planned development. Although it does not necessar- ily protect for the most conservative reporting surfaces (62.5:1) or a comprehensive set of ob- struction standards, establishment of zoning ordinances based on these and other criteria is critical as FAA can not prevent the construction of any structure, and relies on the local zoning ordinances and authorities having jurisdiction for the enforcement of airspace surrounding airports. Implementation of these criteria involves the establishment of an airport land use map, depicting the FAR Part 77 civil airport imaginary surfaces, and the establishment of a review board to hear appeals and special cases for the establishment of proposed construction. This advisory circular provides a good foundation and model for airspace protection regula- tions, but for readers unfamiliar with the range of airspace protection criteria, it may over- simplify the geometric configuration of maximum obstruction and/or no-hazard height, because the civil airport imaginary surfaces (1) are not always the lowest type of obstruction standard, and (2) TERPS surfaces, that in many cases dictate maximum no-hazard height, are in some areas lower than civil airport imaginary surfaces. The authors of this ACRP research project hope that the Report and Guidebook will serve as useful supplements to the technical and policy guidance contained in the advisory circular. 54 Understanding Airspace, Objects, and Their Effects on Airports Figure A.6. AOSC Decision Document example: clarification of the TERPS 40:1 departure surface.

FAA Advisory Circular 150/5070-6B, Airport Master Plans Latest amendment May 2007 http://www.faa.gov/airports_airtraffic/airports/resources/advisory_circulars/media/ 150-5070-6B/150_5070_6b_chg1.pdf Purpose The criteria contained in this advisory circular provide guidance for the preparation of mas- ter plans for airports of all sizes and types. They include basic airspace protection criteria related to runway planning. Function These criteria serve to identify the function of an airport Master Plan, its content, and the planning activities that are required to develop the document. They further identify the ele- ments of a Master Plan including public involvement, environmental considerations, and inventory of existing conditions, aviation forecasts, facilities requirements, alternatives for development, evaluation of alternatives, airport master plans, document facilities implemen- tation plans, and financial analyses. Application of Criteria These criteria are applied when an airport sponsor prepares a Master Plan or a Master Plan Update. The elements in a Master Plan focusing on future development plans and the develop- ment of an ALP set of drawings directly address navigable airspace. Obstruction clearance issues must be considered if any of the following are proposed: 1) a new runway; 2) change to runway configuration, including new applications of, or adjustments of, declared distances; 3) changes to existing obstructions; and 4) change to flight procedures. The development of an ALP includes an airspace analysis that shows the civil airport imagi- nary surfaces drawings based on FAR 77.25 for the ultimate planned development alternative, and a set of departure drawings including the 40:1 TERPS departure surface and the 62.5:1 one engine inoperative obstacle identification surface. When an ALP is submitted for review by the airport to FAA, it follows an approval process defined in JO 7400.2. As part of this process, FAA is required to conduct an aeronautical study of the future development alterna- tive. Once an ALP set is approved by FAA, all future OE/AAA cases must consider the proposed runway configuration in addition to existing runway configuration. Airport Design Criteria Various FAA ACs have been issued in order to establish guidance and recommendations pertaining to airport development and design. Airport design criteria are contained within the following:  FAA AC 150/5300-13, Airport Design  FAA AC 150/5300-18, General Guidance and Specifications for Submission of Aeronautical Sur- veys to NGS: Field Data Collection and Geographic Information System (GIS) Standards  FAA AC 150/5390-2A, Heliport Design  FAA AC 150/5395-1, Seaplane Bases  FAA Order 6750, Siting for Instrument Landing Systems  FAR Part 139, Certification of Airports  FAR Part 157, Notice of Construction, Alteration, Activation, and Deactivation of Airports The Purpose, Function, and Application of Criteria 55

The following sections discuss the purpose, function, and application of criteria contained in each of the documents listed above. FAA AC 150/5300-13, Airport Design Latest amendment November 2008 http://www.faa.gov/airports_airtraffic/airports/resources/advisory_circulars/ Purpose FAA AC 150/5300-13 was first published in 1989 with the purpose of establishing the FAA’s general standards and recommendations for airport design. For example, some of the specific direction provided in this AC includes basic airport geometry standards such as:  Runway, taxiway, and taxilane design standards  Surface gradient and line-of-sight standards  Siting requirements for NAVAID and ATC facilities  Guidance for the establishment of the airport reference point (ARP)  Wind analysis standards AC 150/5300-13 serves as the principal reference document pertaining to FAA standards for airport design. Function The intended function of AC 150/5300-13 is to provide the guidance needed in order to develop and maintain a national system of safe, delay-free, and cost-effective airports. The standards and recommendations contained in this publication do not serve to limit or regulate the operation of aircraft. AC 150/5300-13 details many facets of airport design. Obstacle analysis is one of many topics covered in this publication. Certain aspects of AC 150/5300-13 should be considered when performing on-airport obstruction analysis. For example, the design standards outlined in AC 150/5300-13 dictate that certain areas, such as runway safety areas, runway protection zones, runway object free areas, and taxiway safety areas, etc., be kept essentially free of any obstruc- tions. In addition, siting requirements for NAVAID and ATC facilities outlined in this AC dic- tate that certain areas are kept free of obstructions that may interfere with signals and lines-of-sight associates with these facilities. Application of Criteria The criteria contained in this AC apply to airports and are also used by specialists in the FAA Air- ports Division to evaluate proposed construction on airport. The standards and recommenda- tions contained within AC 150/5300-13 are recommended by the FAA for application in the design of all civil airports. For airport projects receiving Federal grant-in-aid assistance, the use of these standards is mandatory. At certified airports, the standards and recommendations pro- vided by AC 150/5300-13 may be used to satisfy the requirements of FAR Part 139, Certification and Operations: Land Airports Serving Certain Air Carriers, Subpart D. The following paragraphs and figures provide examples of Appendix 2 runway end siting cri- teria, the primary geometric criteria used to determine how close to existing obstacles certain defined points of a runway may be sited, namely (1) the threshold (the first part of the run- way available and suitable for landing) (Figure A.7), and (2) the departure end of runway (or DER, the point at which a departing aircraft must become airborne) (Figure A.8). Both of these defined points are routinely co-located with the runway pavement endpoint, but may be inset or “displaced” from the endpoint, if obstacle clearance requirements for departing or 56 Understanding Airspace, Objects, and Their Effects on Airports

The Purpose, Function, and Application of Criteria 57 Figure A.7. From AC 150/5300-13, Appendix 2, Runway End Siting Criteria: Threshold Siting Surface. Figure A.8. From AC 150/5300-13, Appendix 2, Runway End Siting Criteria: Departure Siting Surface.

Table A.1. From AC 150/5300-13, Appendix 2. arriving aircraft require. The emphasis of this appendix is that a new object that penetrates a critical runway end siting surface may result in serious impacts on the use of the runway by requiring the critical points to be moved, resulting in a reduction of usable runway length, which, in most cases, will incrementally reduce the capacity of that runway. As a companion to Appendix 2, Appendix 14 (‘Declared Distances’) prescribes the usable length reductions that must be made in order for the runway to be in compliance with runway end siting and other airport design standards. Table A.1 is Table A2-1 from AC 150/5300-13, Appendix 2. It specifies the dimensions of threshold siting surfaces and departure end siting surfaces, which depend on the runway type, approach type, and other factors, including the following: 58 Understanding Airspace, Objects, and Their Effects on Airports

The Purpose, Function, and Application of Criteria 59  Whether or not the runway is authorized for a visual, nonprecision, precision approaches, nighttime operations, and the approach visibility minimums.  Whether or not there are published instrument departure procedures on the runway.  Whether or not the runway is used by scheduled air carriers (those operating under FAR Part 121). and  The approach category of the runway’s design aircraft. In many cases the requirements for maintaining airspace clear of objects depend, in part, on the type of aircraft that typically use a runway. Airport runway design standards are based, in fact, on what is known as the runway’s “design aircraft.” Design Aircraft: A design aircraft is one that is deemed to be most critical to the design of a runway, and that is planned to use the runway for at least 500 itinerant operations annu- ally. A runway may be designed with a number of different design aircraft. For example, a very large aircraft may be the design aircraft when it comes to runway length specifica- tions, while a very small aircraft may be the design aircraft when designing for runway ori- entation, while yet another may be used to design the pavement specifications of the runway. For the purposes of airspace protection, the aircraft with the greatest “approach speed” is used. Design Aircraft Approach Category: The approach speed is the airspeed that the aircraft is designed to be traveling while on approach to the runway. Based on the approach speed of the design aircraft, the runway is given an Aircraft Approach Category. This category is a letter from A to E, based on the following: Aircraft Approach Category Category Approach Speed A < 91 knots B 91–120 knots C 121–140 knots D 141–166 knots E > 166 knots Once these parameters are established, refer to Table A.1 (Table A2-1 from Appendix 2) for specific dimensions. Please note that additional coordination with TERPS criteria and airline-specific OEI criteria is necessary for some types of runway end siting surfaces. FAA AC 150/5300-18, General Guidance and Specifications for Submission of Aeronautical Surveys to NGS: Field Data Collection and Geographic Information System (GIS) Standards Latest amendment 150/5300-18B, May 2009 http://www.faa.gov/airports_airtraffic/airports/resources/advisory_circulars/index.cfm? template=Document_Listing&Keyword=150/5300-18 Purpose FAA AC 150/5300-18 provides the specifications for the collection of airport data via field and office methodologies in support of the FAA. It also stipulates how the data is to be submitted to FAA and who will then forward the safety critical data to the National Geodetic Survey (NGS) for their independent verification and validation. The primary purpose of the guidelines con- tained in this advisory circular is to establish the requirements for data collection and process- ing conducted at airports in support of the FAA Airport Surveying-GIS Program.

Function The standards presented in this publication provide information that is “critical to the oper- ation and safety of the National Airspace System (NAS)”. The International Civil Aviation Organization (ICAO) classifies data as critical when “there is a high probability when using cor- rupted critical data that the continued safe flight and landing of an aircraft would be severely at risk with the potential for catastrophe”. Figure A.9 depicts the “Airport Airspace Survey Surfaces,” a set of surfaces that are similar to, but generally wider and lower than, the FAR Part 77 Civil Airport Imaginary Surfaces. The function of the Airport Airspace Survey Surfaces is as a screening tool—any object that pen- etrates any of these surfaces must be catalogued in the airport airspace survey. The surfaces 60 Understanding Airspace, Objects, and Their Effects on Airports Figure A.9. Airport airspace survey surfaces.

shown in the example are for airports whose runways have vertical guidance (vertically- guided approaches). Other surfaces apply for runways without vertical guidance. See Section 2.7 of the AC for more detail. The surfaces shown on the figure are as follows: ✈ Vertically Guided Runway Primary Surface (VGRPS) ✈ Vertically Guided Primary Connection Surface (VGPCS) ✈ Vertically Guided Approach Surface (VGAS) ✈ Vertically Guided Protection Surface (VGPS) ✈ Vertically Guided Approach Transitional Surface (VGATS) ✈ Vertically Guided Horizontal Surface (VGHS) ✈ Vertically Guided Conical Surface (VGCS) The guidance provided in AC 150/5300-18 encompasses the entire range of the FAA’s airport data requirements. This includes but is not limited to: runway and stopway data; navigational aid data; obstruction data; and data on various airport features including taxiways, aprons, landmark features, and airspace obstructions. Most of this data is source data, acquired by field survey or remote sensing methods. The methodology described in this publication should be used when gathering data to be used for obstacle analysis efforts related to airport improvement projects. Criteria define obstacle survey surfaces, screening for obstacles that must be included in the 3D database. Application of Criteria The FAA recommends the guidelines provided in this AC for the collection of geospatial airport and aeronautical data. Compliance with these guidelines is mandatory for the collection of geospatial airport and aeronautical data for airfield improvement projects funded by Federal grant assistance programs. This AC also provides one, but not the only, means of meeting the requirements for the collection of geospatial airport and aeronautical data stipulated by CFR Part 139, Certification of Airports. The obstacles identified as part of these surveys are entered into a database and are considered when preparing instrument flight procedures at each airport. FAA AC 150/5390-2A, Heliport Design Latest amendment January 2004 http://rgl.faa.gov/Regulatory_and_Guidance_Library%5CrgAdvisoryCircular.nsf/0/A1CC45 66A988F08986256C6A00721BC6?OpenDocument Purpose FAA AC 150/5390-2 provides recommendations for heliport design and describes acceptable requirements for the development of a heliport. This AC applies to any individual or entity that is proposing to construct, modify, activate, or deactivate a heliport within the NAS. Function The intended function of AC 150/5390-2 is to provide the guidance necessary to develop and maintain safe, efficient, and cost-effective heliports. The standards and recommendations contained in this publication do not serve to limit helicopter or heliport operations. AC 150/5390-2 is essentially the heliport counterpart to AC 150/5300-13. It is a wide-ranging document covering nearly every facet of heliport design including basic obstruction analysis. Certain aspects of this AC should be considered when performing obstacle analysis on heli- port property. For example, the design standards outlined within this publication dictate that certain areas, such as final approach reference areas, safety areas, certain protection zones, etc., be kept free of any obstructions (see Figure A.10). The Purpose, Function, and Application of Criteria 61

Application of Criteria The standards and recommendations contained within AC 150/5390-2 are generally recom- mended by the FAA for application in the design of heliports. For heliport projects receiving Fed- eral grant assistance, the use of these standards is mandatory. These recommendations and standards are predicated on average conditions. Adaptation to meet the specific conditions of a particular site may be necessary. To the greatest extent possible, the standards contained in AC 150/5390-2 should be used when planning and designing improvements to existing heliports. FAA Advisory Circular 150/5395-1, Seaplane Bases Latest amendment June 1994 http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/79 ADABA388B6BE6186256C6A00721C2A?OpenDocument&Highlight=seaplane%20bases Purpose FAA AC 150/5395-1 provides guidance to assist operators in planning, designing, and con- structing seaplane base facilities. Function The intended function of AC 150/5395-1 is to provide the guidance needed in order to develop and maintain safe, efficient, and cost-effective seaplane bases. The standards and recommenda- tions contained in this publication do not serve to limit or regulate the operation of aircraft. AC 150/5395-1 is a comprehensive document detailing seaplane base planning, design, and construction. Basic obstacle analysis is described in this publication. Criteria pertain- 62 Understanding Airspace, Objects, and Their Effects on Airports Figure A.10. Heliport approach/departure surfaces.

ing to seaplane bases differ from those for airports. For example, FAR Part 77 applies to seaplane bases only if the sea lanes are outlined by visual markers. This AC covers the FAA process for the study of existing objects. As with airports, it is necessary to submit 7460-1 forms for proposed construction or alteration of structures on, or in the vicinity of a sea- plane base. Application of Criteria Establishment of a new seaplane base or modification of a seaplane base requires advance notification to the FAA. In support of such establishment or notification, FAA recommends the design embody the guidance provided by AC 150/5395-1. FAA Order 6750, Siting Criteria for Instrument Landing Systems Latest amendment February 2004 http://www.airweb.faa.gov/ Purpose The purpose of FAA Order 6750 is to provide engineering guidance pertaining to the siting of FAA ILS. Because ILS siting conditions vary site to site, it is not possible for the FAA to pro- vide guidance on overcoming or offsetting the potential effects of every potential adverse con- dition. This order provides guidelines that are to be used in conjunction with a thorough understanding of ILS facility operations in order to determine the optimum site and operat- ing conditions. Function The intended function of FAA Order 6750 is to provide sufficient information, along with supporting drawings, to enable the selection of the optimum ILS site, within defined limits, for each of the subsystems that comprise Category I, II, or III ILS systems. Subsystems that may comprise an ILS installation include localizer antennas, glide slope antennas, marker bea- cons, and approach lighting systems. The criteria in this Order should be taken into consideration when conducting an obstruction analysis for proposed structures near an airport utilizing one or more ILS systems or an air- port that has a planned ILS system. The Order specifies critical areas that must be free of cer- tain types of obstructions in order to ensure the continuous integrity of the signal received by the aircraft, and visibility of approach lighting. Application of Criteria The criteria applied in FAA Order 6750 apply only to newly established or relocated ILS facil- ities to include Localizer, Marker Beacon, Localizer-Type Directional Aids, and Offset Local- izers. Additional criteria are accessible for Non-Directional Beacon and Distance Measuring Equipment (DME) specific to collocation with ILS facilities. It is not required that existing facilities be changed for the sole purpose of compliance with the latest criteria established in this Order. FAR Part 139, Certification of Airports Latest amendment June 2004 http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/Frameset?OpenPage The Purpose, Function, and Application of Criteria 63

Purpose FAR Part 139 establishes certification requirements for airports. FAR Part 139 requires the FAA to issue airport operating certificates to airports that:  Serve scheduled and unscheduled air carrier aircraft with more than 30 seats;  Serve scheduled air carrier operations in aircraft with more than 9 seats but less than 31 seats; and  The FAA Administrator determines are required to have a certificate. This regulation does not apply to airports at which air carrier passenger operations are conducted only because the airport has been designated as an alternate airport. The regulation allows the FAA to issue certain exemptions to airports that serve low numbers of passengers on a yearly basis, and for which some of the requirements might create undue financial hardship. Function Airport Operating Certificates serve to promote a consistent level of safety in air transporta- tion. To obtain a certificate, an airport must agree to certain operational and safety standards and provide for such facilities as firefighting and rescue equipment. These requirements vary depending on the size of the airport and the type and number of flights available. The FAA inspects the airport periodically in order to ensure compliance. Certain aspects of this regulation must be considered when conducting obstruction analyses pertaining to airports. Paragraph 139.331 addresses obstructions specifically and states: In a manner authorized by the Administrator, each certificate holder must ensure that each object in each area within its authority that has been determined by the FAA to be an obstruction is removed, marked, or lighted, unless determined to be unnecessary by an FAA aeronautical study. FAA Advisory Circulars contain methods and procedures for the lighting of obstructions that are acceptable to the Administrator. Safety areas and protection of NAVAIDS are also covered in this regulation. These aspects of the airport certification regulations must also be considered when conducting obstruction analyses. Application of Criteria Generally, airports in any state of the United States, the District of Columbia, or any territory or possession of the United States, serving passenger-carrying operations of an air carrier cer- tificated under FAR Part 121 and FAR Part 380 must hold Airport Operating Certificates if:  Scheduled passenger-carrying operations are conducted in aircraft designed for more than 9 passenger seats; and  Unscheduled passenger-carrying operations are conducted in aircraft designed for at least 31 passenger seats The authorizing statute exempts Alaskan airports that serve air carrier aircraft with less than 30 seats from Federal airport certification requirements. Also, any such airport that either leases from or shares its facility with the U.S. Government, such as the Department of Defense, must obtain a Part 139 Airport Operating Certificate for those portions of a joint-use or shared-use airport that are within the authority of a person serving passenger-carrying oper- ations defined above. FAR Part 157, Notice of Construction, Alteration, Activation, and Deactivation of Airports Latest Amendment July 1991 http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?c5ecfr&rgn5div5&view5text&node514:3.0. 1.3.24&idno514 64 Understanding Airspace, Objects, and Their Effects on Airports

Purpose FAR Part 157 establishes notification requirements for construction, alteration, activation, and deactivation of airports and/or take-off or landing area components of airports, for those airports that are not required to have an approved ALP on file with the FAA. The FAA must be made aware of all airports and landing areas in the U.S. airspace, irrespective of size, in order to investigate airspace interactions, airspace obstructions, land use compatibility, and other considerations. Function FAR Part 157 functions as a means for the FAA to be notified and to make airspace determi- nations and other types of determinations for the large number of non-public and small pub- lic airports that either do not receive Federal assistance, or for other reasons are not routinely represented with ALPs. These can include small general aviation airports, heliports, seaplane bases, rooftop helipads, gliderports, and the like. Application of Criteria Sponsors of airport and/or landing area proposals that fall under FAR Part 157 are required to file FAA Form 7480-1, Notice of Landing Area Proposal, with the FAA ADO having jurisdiction. The FAA Airports Division will assign a non-rulemaking airport (NRA) case number, and will process the form in accordance with FAA Order 7400.2, Part 3 (Chapters 10, 11, and 12), with appropriate coordination among other FAA divisions and other stakeholders, and will sub- sequently issue determinations. Flight Procedure Design Criteria Various FARs, FAA Orders and AC have been issued in order to establish guidance and rec- ommendations pertaining to instrument flight procedure design. The criteria contained in these documents also inform the OE/AAA process when the FAA evaluates the effects a proposed structure would have on a specific procedure. Flight procedure design criteria are defined in the following documents:  FAA Order 8260.3B, The United States Standard for Terminal Instrument Procedures (TERPS)  TERPS Derivative Orders (8260 series)  TERPS Instruction Letters (TILs)  FAA AC 90-80B, Approval of Offshore Standard Approach Procedures, Airborne Radar Approaches, and Helicopter En Route Decent Areas  FAR Part 25, Airworthiness Standards: Transport Category Airplanes  FAA AC 120-91, Airport Obstacle Analysis  FAA AC 120-29A, Criteria for the Approval of Category I and II Weather Minima for Approach  FAA AC 120-28D, Criteria for the Approval of Category III Weather Minima for Takeoff, Landing, and Rollout  FAR Part 121, Operating Requirements: Domestic, Flag, and Supplemental Operations  FAA Handbook, FAA-H-8261-1A, Instrument Procedures Handbook  FAA Air Traffic Publication, Aeronautical Information Manual  FAA, National Aeronautical Charting Office (NACO) Website FAA Order 8260.3B, The United States Standard for Terminal Instrument Procedures (TERPS) Latest amendment Change 20, December 2007 http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgOrders.nsf/0/12B3D4C9B 4F46DCE862572D700538895?OpenDocument&Highlight58260.3b The Purpose, Function, and Application of Criteria 65

Purpose This order prescribes standardized methods for use in designing instrument flight proce- dures. The criteria contained in this Order must be used to formulate, review, approve, and publish procedures for instrument flight operations to and from civil and military airports. The Flight Procedure Standards Branch, AFS-420, of the Flight Technolo- gies and Procedures Division, AFS-400, is responsible for the rulemaking process of the Flight Procedures program which includes development, application, and oversight of the National Flight Procedures Program and development of criteria pertinent to designing instrument flight procedures. This includes all of the 8260 Series Orders, approximately 20 in number. Function FAA Order 8260.3B is designed to provide the instrument flight procedure developer with the criteria to safely and efficiently construct instrument flight procedures in accordance with standardized regulatory framework. This framework includes the evaluation of existing and proposed obstructions, in the NAS. Application of Criteria The instrument flight procedure developer uses the criteria contained within Order 8260.3B to develop a particular instrument flight procedure, such as a precision approach to a certain runway at a certain airport. Much of the process guidance contained within this Order has also been programmed into the FAA Instrument Approach Procedure Automation (IAPA) System. This offers the instrument flight procedure developer the ability to use the automated system to develop the majority of instrument procedures. TERPS criteria are designed to provide a margin of safety, known as ROC, between air- craft in flight and permanent objects, including terrain, vegetation, and manmade objects. After mapping the runways, terrain, and critical obstacles, the procedure designer (human or computer) applies the criteria to develop the specific flight path. Criteria for different systems of instrumentation are different based on the horizontal and vertical margins of error (i.e., deviation of actual versus reported flight path) known for each system of instrumentation. For each segment of each procedure, an obstacle accountability area (OAA) is first developed. The OAA is a two-dimensional area showing the limits of where obstacles need to be consid- ered for the particular flight procedure. Based on the flight path and ROC, the OIS is con- structed next at default or ideal alignments. If the OIS is found to be clear of obstacles, it functions as an obstacle clearance surface (OCS), and the procedure can have optimal flight path parameters. For certain types of procedures, if the OIS is found to have penetrating obstacles, an alternative OCS is created that clears the obstacles, and/or the visibility mini- mums of the procedure are raised from the ideal elevations upwards to an elevation where the penetrating obstacle would not cause a reduction in minimum ROC (see Figure A.11). For other types of procedures, any penetration of crucial surfaces such as the glidepath qualifica- tion surface (GQS) or visual segment are not allowed; if penetrations are found, they must be removed, otherwise the procedure is not authorized. In the OE/AAA process, either the manual construction or the automated system, or a com- bination therein, will be used to evaluate the effects of proposed or existing construction on existing or proposed instrument flight procedures. These criteria apply at any location where an appropriate U.S. agency exercises jurisdiction. Instrument flight procedures can be “reverse engineered” to depict large-scale representations of the OCSs to develop airspace sur- face mapping (see Figure A.12). 66 Understanding Airspace, Objects, and Their Effects on Airports

TERPS Derivative 8260 Series Orders http://www.faa.gov/regulations_policies/orders_notices/index.cfm?fuseAction=c.dspTopic Browse&parentTopicID=16  8260.4 ILS Obstacle Risk Analysis  8260.15E United States Army Terminal Instrument Procedures Service  8260.16 Airport Obstruction Surveys  8260.19D Flight Procedures and Airspace  8260.23 Calculation of Radio Altimeter Height  8260.31B Foreign Terminal Instrument Procedures  8260.32D U.S. Air Force Terminal Instrument Procedures Service  8260.37 Helicopter Civil Utilization of Collocated Microwave Landing Systems (MLS)  8260.40B Flight Management System (FMS) Instrument Procedures Development  8260.42A Helicopter Global Positioning System (GPS) NonPrecision Approach Criteria  8260.43A Flight Procedures Management Program  8260.44A CHG 2 Civil Utilization of Area Navigation (RNAV) Departure Procedures  8260.45A Terminal Arrival Area (TAA) Design Criteria  8260.46C CHG 1 Departure Procedure (DP) Program  8260.49A Simultaneous Offset Instrument Approach (SOIA)  8260.52 United States Standard for Required Navigation Performance (RNP) Approach Procedures with Special Aircraft and Aircrew Authorization Required (SAAAR)  8260.53 Standard Instrument Departures That Use RADAR Vectors To Join RNAV Routes  8260.54A The United States Standard for Area Navigation (RNAV)  N8260.64 Radar Approaches and Minimum Vectoring Altitudes—Current Guidance and Criteria  N8260.65 Guidelines for Application of Glidepath Qualification Surface (GQS)  7130.3A Holding Pattern Criteria The Purpose, Function, and Application of Criteria 67 Figure A.11. Illustration of flight paths, obstacle identification surface (OIS), obstacle clearance surface (OCS) and required obstacle clearance (ROC) concepts, as applied to TERPS obstacle departure procedures.

68 Understanding Airspace, Objects, and Their Effects on Airports Figure A.12. TERPS final approach and missed approach as illustrated for generic vertically- guided approach.

Purpose As new types of instrumentation technology are developed, the FAA publishes new Orders describing how procedures should be developed that utilize new types of instrumentation. Function The various 8260 Series Orders are designed to provide the instrument flight procedure developer with guidance in the development, evaluation, and analysis of various facets, different types of instrument procedures that supplement, and/or address additional air- space design that is not an integral part of the basic TERPS Order 8260.3B. These include, but are not limited to, Instrument approach procedure development, departure develop- ment, risk assessment and terminal area design. The majority of the Orders address vari- ous types of air navigation including the use of conventional NAVAIDS, Radar and Area Navigation (RNAV) along with GPS. They also address special procedures such as helicop- ter operations. Application of Criteria Each of the various 8260 Series Orders provide additional guidance for specific new procedure technology to the Airspace Specialist that is not fully contained within Order 8260.3B. This provides the Airspace Specialist with the ability to analyze and develop instrument procedures that require additional information, criteria and guidelines. Of the 8260 Series Orders, FAA Order 8260.19 provides additional guidance to Airspace Specialists during the Obstruction Evaluation process. Order 8260.19 provides guidance to all FAA personnel for the administration and accomplishment of the FAA Flight Proce- dures and Airspace Program. It specifically requires that the National Flight Procedures Office (FPO) ensure that a complete evaluation of the effect that any proposed construc- tion or alterations will have on IFR aircraft operations, including the visual portion of an IFR procedure, is conducted. TERPS Instruction Letters (TILs) http://www.faa.gov/about/office_org/headquarters_offices/avs/offices/afs/afs400/afs420/ policies_guidance/tils/  99-003 Taxiing Aircraft as Departure Obstructions; AVN-160 E-Mail  99-014 Adding Descent Angles to Nonprecision Approach Charts  00-009 Successive Fly-over Waypoints  00-012 Paragraph 252, Descent Angle/Gradient  00-015 Airport Reference Code (ARC) Application  00-016 Interim United States Army Helicopter Departure Criteria  01-020 FAA Order 8260.44 Interim Change 1  01-024 Construction Criteria for Leg Segments VA to CF  01-025 Turning Area Curve Radii at 10,000 Feet MSL  02-039 Guidance on the Use of RNAV-Pro Software to Pre-Screen Instrument Procedures  02-042 Area Navigation (RNAV) “Q” Route Processing  02-043 United States Standard for TERPS Change 19, Correction #1  03-048 Interim Correction to Order 8260.3B, United States Standard for Terminal Instru- ment Procedures (TERPS) Purpose TERPS Instruction Letters (TILs) are intended to provide interim guidance and/or clarifica- tion to a particular Order until a revision to the Order is accomplished. The Purpose, Function, and Application of Criteria 69

Function The TIL provides the Airspace Specialist clarification or additional guidance when conduct- ing an airspace evaluation, when some portion of TERPS criteria may be incomplete, ambigu- ous, in conflict with other criteria, or outdated. Application of Criteria TILs are applied in a similar manner to full TERPS orders in the OE/AAA process and flight procedure development process. FAA AC 90-80B, Approval of Offshore Standard Approach Procedures, Airborne Radar Approaches, and Helicopter En Route Descent Areas Latest amendment April 1992 http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/key/AC% 2090-80B Purpose This AC 90-80B provides criteria and describes acceptable methods for obtaining approval to use the Offshore Standard Approach Procedure (OSAP), the Airborne Radar Approach (ARA) and the Helicopter En Route Descent Area (HEDA) and useful information for obstruction evaluation as the process relates to flight procedures. Function The criteria for developing offshore approaches are unlike those used for SIAP. This AC pro- vides additional criteria for offshore approach course alignments that may vary from one approach to the next. Application of Criteria The Airspace Specialist uses these criteria when determining whether or not proposed struc- tures may impact the offshore approaches, airborne radar approaches or helicopter operations. FAR Part 25, Airworthiness Standards: Transport Category Airplanes Latest amendment September 2008 http://ecfr.gpoaccess.gov/cgi/t/text/text-idx?&c=ecfr&tpl=/ecfrbrowse/Title14/14tab_02.tpl Purpose FAR Part 25 provides strict technical regulations for aircraft compliance during takeoff, landing, and during one engine inoperative procedures. Transport category aircraft must be in compliance with a variety of airworthiness standard criteria to receive certification for airworthiness. Function The guidelines described a variety of criteria for aircraft evaluation including performance, controllability and maneuverability, trim, stability, stalls, ground and water handling characteristics, and other miscellaneous flight requirements. Individual air carriers can use the guidance in FAR Part 25 to determine compliance for takeoff, landing, and OEI procedures. 70 Understanding Airspace, Objects, and Their Effects on Airports

Application of Criteria This AC provides information on the performance requirements of aircraft, which in turn determines the appropriate flight profiles of arriving and departing aircraft from runways. These profiles in turn contribute to determining flight procedures, under both normal and one-engine-inoperative conditions, for airport runways, given existing surrounding terrain or other objects in the vicinity. FAA AC 120-91, Airport Obstacle Analysis Latest Amendment May 2006 http://www.airweb.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/0/55 a6248632ed6e8d86257184005a2188/$FILE/AC120-91.pdf Purpose This advisory circular describes acceptable methods and guidelines for developing takeoff and initial climb-out airport obstacle analyses and in-flight procedures to comply with the intent of the regulatory requirements of FARs, and other associated OEI requirements relating to turbine engine powered airplanes operated under FAR Parts 121 and 135. Function The methods and guidelines described in this AC have been derived from extensive FAA and industry experience and are considered acceptable to the FAA when appropriately used. Indi- vidual air carriers can use the guidance in AC 120-91 as a framework to develop emergency OEI flight procedures. Application of Criteria This AC provides information for determining safe clearance from obstacles for the actual flight path, and for considering factors that may cause a divergence of the actual flight path from the intended flight path. Each airline is required to develop OEI procedures for each runway at each airport. Each has their own procedures, but all must be approved by the FAA. OEI procedures are constructed similar to TERPS procedures. The airline flight operations engineer begins with a basemap of the runways, terrain, and obstacles. An ideal OEI flight path is developed, accounting for reduced climb performance resulting from loss of power to one engine. An OAA or “splay” ( see Figure A.13) is applied to obstacles in the flight path, and the procedure designer reviews the obstacle clearance between the flight path and obstacles within the OAA. If the obstacle clearance is less than required, the flight path must be adjusted, either upwards (by reducing take-off weight), or incorporating a turn to avoid the obstacle. Both of these adjustment options are undesirable. Reducing takeoff weight (some combination of pas- sengers, fuel, and cargo), known as a “weight penalty,” can have a substantial negative finan- cial impact on the flight, or it may make the flight technically infeasible. Incorporating turns into an emergency procedure is undesirable, since it adds a layer of complexity to an extremely stressful situation for the pilot. Proposed construction may adversely impact one or more airlines’ OEI procedures, even if it would not affect any TERPS procedures. Air carriers, their representatives, or other stake- holders may file OEI-related comments under Public Notice when the FAA is conducting an aeronautical study. The Purpose, Function, and Application of Criteria 71

FAA AC 120-29A, Criteria for Approval of Category I and Category II Weather Minima for Approach Latest Amendment August 2002 http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/key/AC%2012 0-29A Purpose This AC provides an acceptable means, but not the only means, for obtaining and maintain- ing approval of operations in Category I and II Landing Weather Minima including the instal- lation and approval of associated aircraft systems. Function Approach weather minima are approved through applicable operating rules use of approved instrument procedures and issuance of Operations Specifications (Op-Specs). Op-Specs are unique FARs applicable to a particular operator. Op-Specs are based on the regulations; how- ever, they are specifically applicable to and tailored to a particular operator’s aircraft, routes, and operating circumstances. Application of Criteria Instrument Approach procedures in the United States and its territories must be validated by an authorized FAA process. This includes the obstruction evaluation process for objects in approach and missed approach areas. 72 Understanding Airspace, Objects, and Their Effects on Airports Figure A.13. Illustration of the standard OEI OAA from AC 120-91.

FAA AC 120-28D, Criteria for Approval of Category III Weather Minima for Takeoff, Landing, and Rollout Latest Amendment July 1999 http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgAdvisoryCircular.nsf/8ce3f88c034ae 31a85256981007848e7/bbada17da0d0bbd1862569ba006f64d0/$FILE/AC120-28D.pdf Purpose This AC provides an acceptable means, but not the only means, for obtaining and maintain- ing approval of operations in Category III Landing Weather Minima and low visibility take- off including the installation and approval of associated aircraft systems. Function The main body of this AC contains criteria related to operational approval. The provisions of the main body of this AC outline concepts, objectives, and provisions necessary for operators. Application of Criteria Instrument Approach procedures in the United States and its territories must be validated by an authorized FAA process. This includes the obstruction evaluation process for objects in approach and missed approach areas. FAR Part 121, Operating Requirements: Domestic, Flag, and Supplemental Operations Latest amendment December 2007 http://ecfr.gpoaccess.gov/cgi/t/text/textidx?c=ecfr&tpl=/ecfrbrowse/Title14/14cfr121_main_ 02.tpl Purpose This regulation mandates certain criteria for air carrier operators. Among the require- ments are minima for approaches, departures, and weather. The regulation also mandates air carriers to develop an OEI procedure for every runway that they serve based on crite- ria such as the most restrictive aircraft by performance, average warm temperature, and obstacles. Function FAR Part 121 is the primary operating regulation under which commercial air carriers oper- ate. Adherence to these regulations is required to maintain an air carriers operating certificate. Application of Criteria Within FAR Part 121 is the requirement that air carriers develop procedures for the event where an engine failure is experienced upon takeoff. These procedures, known as OEI pro- cedures, typically involve an emergency climb out at the maximum feasible climb rate to a given altitude, followed by a procedure for maneuvering back to the airport for landing. In determining these procedures, consideration is given to the type and operating weight of each aircraft operation, as well as the local environmental conditions (field elevation and outside air temperature), and the existing surrounding terrain and other objects in the vicinity of the airport. The Purpose, Function, and Application of Criteria 73

FAA-H-8261-1A, Instrument Procedures Handbook Latest Amendment 2007 http://www.faa.gov/library/manuals/aviation/instrument_procedures_handbook/media/FA A-H-8261-1A.pdf Purpose This Handbook is designed as a technical reference for professional pilots who operate under IFR in the NAS. Function The Instrument Procedures Handbook provides detailed coverage of instrument charts and procedures including IFR takeoff, departure, en route, arrival, approach, missed approach, and landing. Application of Criteria The Handbook addresses obstacle identification surfaces for approach and departure pro- cedures. It generally informs the reader of the criteria applied; and the expectations of the pilot during departure and arrival. How the FAA protects the obstacle clearance surfaces is relevant to the instrument pilot so that the pilot is aware of the manner in which aircraft is protected. FAA Air Traffic Publication—Aeronautical Information Manual Latest amendment July 2008 http://www.faa.gov/airports_airtraffic/air_traffic/publications/atpubs/aim/ Purpose The Aeronautical Information Manual is designed to provide the aviation community with basic flight information and ATC procedures for use in the NAS of the United States. Function This manual contains fundamental information required in order to fly in the United States NAS. Application of Criteria The Handbook addresses obstacle identification surfaces for approach and departure proce- dures. It generally informs the reader of the criteria applied; and the expectations of the pilot during departure and arrival. It also expands on the ATC issuance of approach and departure instructions. FAA, National Aeronautical Charting Office Website Updated January 2009 http://www.naco.faa.gov/ Purpose The FAA, National Aeronautical Charting Office (NACO), publishes and distributes United States government civil aeronautical charts and flight information publications. Its URL is http://www.naco.faa.gov/ 74 Understanding Airspace, Objects, and Their Effects on Airports

Function The NACO webpage is a user interactive system allowing for search and the retrieval of instru- ment approach and departure procedure charts. It also allows for the retrieval of Airport Dia- grams, airport obstruction charts, and other types of obstruction databases. Application NACO continuously collects topographic and aeronautical data from a large number of sources and uses this source data to compile and maintain the charts and products provided to the aviation community. This includes the depictions of obstructions that are deemed nec- essary to a safe operation, primarily in the Digital Obstacle File (DOF), a compilation of assumed and actual structure locations based on 7460-1, 7460-2, and final determinations. Flight procedure designers from the FAA and airlines utilize the DOF and NOAA AOC as the primary source data for obstructions. Communication, Navigation, and Surveillance Criteria Various FAA Orders and publications have been issued in order to establish guidance and rec- ommendations pertaining to communication, navigation, and surveillance facilities in the NAS. These criteria are primarily comprised of the following:  FAA Order 6310.6, Primary/Secondary Terminal Radar Siting Handbook  FAA Order 6340.15, Primary/Secondary En Route Radar Siting Handbook  FAA Order 6820.10, VOR, VOR/DME and VORTAC Siting Criteria  NITA Technical Report TR-08-454, Assessment of the Effects of Wind Turbines on Air Traffic Control Radars FAA Order 6310.6—Primary/Secondary Terminal Radar Siting Handbook Latest amendment May 1982 Available for purchase at: http://aero-defense.ihs.com/document/abstract/BCZCDBAAAAAAAAAA Purpose FAA Order 6310.6 provides guidance for selection of Airport Surveillance Radar/ATCBI radar sites to meet FAA operational requirements. Function Order 6310.6 performs the following functions:  Description of the radar and beacon systems with emphasis on siting aspects  Description of several special problem areas of concern with detailed technical data  Details the site selection process: • Preliminary Studies and Selection • Site Surveys including obstacle analysis • Data Analysis • Report Preparation Application of Criteria These criteria are designed for use by FAA engineers for establishing new and/or relocated radar facilities and for the correction of siting problems. All of these scenarios require an adequate The Purpose, Function, and Application of Criteria 75

line of sight from the facility to the intended flight path of the aircraft. Consideration of obsta- cles is an essential component to ensure system performance. An analysis of radar coverage is performed as a standard part of an FAA aeronautical study based on these criteria. FAA Order 6340.15—Primary/Secondary En Route Radar Siting Handbook Latest amendment May 1983 Available for purchase at: http://aero-defense.ihs.com/document/abstract/OHVYDAAAAAAAAAAA Purpose FAA Order 6310.15 establishes specific procedures to be used in the selection of sites for Air Route Surveillance Radar/Air Traffic Control Radar Beacon Interrogator (ARSR/ATCBI) en route facilities. The use of these procedures ensures uniform and objective analysis of candi- date radar sites and allows for the selection of the optimum site. Function This document performs the following functions:  Summarizes operational performances achievable with various en route radars and dis- cusses equipment characteristics as they apply to site selection.  Presents a detailed description of ARSR and ATCBI siting criteria including: • Coverage and Facility Requirements • Coverage Capabilities • Operational Limitations • Site Requirements and Limitations  Step-by-step radar siting procedure including: • Preliminary data acquisition • Preliminary Site Selection • Site Survey • Detailed Site Analysis Application of Criteria These criteria are designed primarily by FAA engineers for siting new FAA en route radar facilities, but may also be applied to facilities relocation and to the correction of siting prob- lems. Consideration of obstacles is an essential component to ensure system performance. An analysis, based on these criteria, of enroute radar coverage is performed as a standard part of an FAA Aeronautical study. FAA Order 6820.10—VOR, VOR/DME and VORTAC Siting Criteria Latest amendment April 1986 Available for purchase at: http://aero-defense.ihs.com/document/abstract/UPVYDAAAAAAAAAAA Purpose This order deals with the procedures and techniques that apply to the initial evaluation, selec- tion, and acquisition of sites suitable for VHF omni-directional range (VOR), VOR/DME, and Tactical Radar (VORTAC) facilities. It also offers guidance on site improvement and the 76 Understanding Airspace, Objects, and Their Effects on Airports

minimization of performance degradation due to multipath. It also provides instruction on the consolidation of buildings and antenna structures associated with those facilities. Function This document describes the following functions:  Overview of Location and Coverage Considerations  Site Evaluation  Site Selection and Acquisition  Site Improvement  Considerations of Longitudinal and Lateral Multipath  Scattering Simulations Application of Criteria The criteria in this document are used by FAA engineers and apply only to new installations and relocations. Existing equipment need not be moved or altered for the sole purpose of complying with this document. The VOR signal integrity and potential degradation due to new obstacles is a consideration of the FAA OE/AAA process. NITA Technical Report TR-08-454—Assessment of the Effects of Wind Turbines on Air Traffic Control Radars July 2008 http://www.its.bldrdoc.gov/pub/ntia-rpt/08-454/ Purpose This order describes the effects that electricity producing wind turbines have on FAA ATC radars. It outlines a process by which it is possible to determine whether a proposed wind farm facility will have adverse effects on current or proposed radar facilities. Function  Review of Literature on Wind Turbine Effects on ATC Radars  Process for Analyzing Wind Turbine and Radar Electromagnetic Compatibility • Line of Sight Distance between Wind Turbines and Radar • Terrain Shadowing Methodology for Assessing the Effects of Wind Turbine Clutter Returns on Radar Performance • Effects of Shadowing on Detection of Desired Targets • Consideration of Wind Turbine Aggregate Effects  Potential for Desired Targets to be Lost in Azimuths Other than those of Wind Turbine Farms  Consideration of the Effects of Wind Turbines on Secondary Radar (ATCBI) Performance Application of Criteria This report is to be used in identifying potential operational conflicts between wind turbines and Air Traffic Control radars and does not pertain to object height and imaginary protection surface penetrations. The Purpose, Function, and Application of Criteria 77