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

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Introduction The jurisdictional authority to limit structure heights through the construction permit process rests with local authorities (some combination of State, County, and/or Local Municipal), and not with the FAA. For optimal land use compatibility and airspace protec- tion, local regulations should reference FAA and/or other types of airspace protections; how- ever, this is not always the case. With respect to local structure height regulations, for any given project site, there are two general classifications of potential structure height: (1) the nominal or standard height limit as set forth in code or ordinance, and (2) the height limit available when an individual pro- posal is granted a variance, e.g., permitted to be taller than standard, after due consideration by authorities. With respect to the FAA OE/AAA process, for any given project site, there are three general classifications of potential structure height: (1) the height requiring FAA notification, (2) the maximum height not exceeding FAA obstruction standards, and (3) the maximum height not exceeding FAA hazard standards. Figure C.1 shows the typical relationships between the various height classifications. As set forth in Title 49 of the U.S. Code of Federal Regulations, §40103, “The United States Government has exclusive sovereignty of airspace of the United States.” In protecting and administering the use of U.S. airspace, The Administrator [of the FAA] shall prescribe air traffic regulations on the flight of aircraft (includ- ing regulations on safe altitudes) for— (A) navigating, protecting, and identifying aircraft; (B) protecting individuals and property on the ground; (C) using the navigable airspace efficiently; and (D) preventing collision between aircraft, between aircraft and land or water vehicles, and between aircraft and airborne objects. The FAA carries out these responsibilities through a variety of means. The primary means by which the FAA analyzes proposed construction or alteration (“protecting individuals and prop- erty on the ground”) that may affect navigable airspace is through the OE/AAA process. The following paragraphs describe the OE/AAA process that is undertaken by the FAA and other parties following receipt of notification from a structure proponent. This process is depicted in logic diagram format at the end of this section. 97 A P P E N D I X C The FAA’s Obstruction Evaluation/ Airport Airspace Analysis Process

Filing of Form 7460-1 A structure proponent must file FAA Form 7460-1, Notice of Proposed Construction or Alter- ation, for any proposed construction or alteration that meets any of the following Notification Criteria described in FAR Part 77.13: §77.13(a)(1) - A height more than 200 feet AGL at its site; §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 no runways greater than 3,200 feet in length, and heliports); §77.13(a)(3) - Roadways, railroads, and waterways are evaluated based on heights above surface pro- viding for vehicles; by specified amounts or by the height of the highest mobile object normally travers- ing the transportation corridor; §77.13(a)(4) - When requested by the FAA, any construction or alteration that would be in an instru- ment 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. Structure proponents or their representatives may file via traditional paper forms via U.S. mail, or online at the FAA’s OE/AAA website, http://oeaaa.faa.gov. Terminology Note: the FAA paperwork and website refer to the party proposing to construct or alter a structure as “sponsor” or “project sponsor”, and (if applicable) the party filing the notification and interfacing with the FAA and stakeholders during the OE/AAA process as the 98 Understanding Airspace, Objects, and Their Effects on Airports Figure C.1. Classifications of potential structure heights.

“sponsor’s representative”. To distinguish clearly from the term “airport sponsor” used to refer to the owner and/or manager of an airport, this text uses the term “proponent” or “structure proponent” to refer collectively to the party proposing to construct or alter a structure, and their representative, if any. Initial Processing of Form 7460-1 FAA follows the following steps to process the Form 7460-1: 1. An aeronautical study number (ASN) is assigned, and data for the case is entered into the OE automation program, the FAA’s internal processing website. 2. An acknowledgement letter is sent to proponent or, in the case of online filing, the data and ASN are immediately available. 3. The FAA Obstruction Evaluation Service (OES) distributes the case to other FAA divisions and related entities (such as military) for review and comment. Initial Aeronautical Study: Obstruction Standards The FAA conducts an initial aeronautical study to determine whether the proposal would exceed obstruction standards under the provisions of FAR Part 77.23. An object constitutes an obstruction to air navigation if any of the following obstruction standards are exceeded: §77.23(a)(1) - A height more than 500 feet AGL at the object site. §77.23(a)(2) - A height AGL or above the airport elevation, whichever is greater, exceeding 200 feet within 3 nautical miles (NM) of the ARP, and that height increases at a rate of 100 fpnm up to 500 feet within 6 miles. §77.23(a)(3) - A height that increases a minimum instrument flight altitude within a terminal area. This standard references instrument procedure criteria such as TERPS. §77.23(a)(4) - A height that increases a minimum obstruction clearance (MOCA) under en-route criteria. §77.23(a)(5) - The surface of a take-off and landing area of an airport or any imaginary surface defined in later sections: §77.25 for civil airports, §77.28 for military airports, and §77.29 for heliports. Of note: FAR Part 77 as a whole, or FAR Part 77 obstruction standards, are sometimes nar- rowly understood only to be constituted of the imaginary surfaces referenced in §77.23(a)(5) and defined in §77.25. However, FAR Part 77 is an entire set of regulations; and there are five distinct types of obstruction standards, as listed above. Initial Aeronautical Study Results The FAA issues one of the following responses after conducting the initial aeronautical review: • If the project does not meet notice criteria, or does not exceed obstruction standards, a DNH with DNE status is issued with no expiration date and no marking/lighting requirements. • If the project exceeds notice criteria, but does not exceed obstruction standards and is 200 feet AGL or less, a DNH with DNE status is issued with no expiration date and no marking/lighting is necessary. • If the project exceeds notice criteria, but does not exceed obstruction standards and is more than 200 feet AGL, a DNH is issued with appropriate marking/lighting recommendations. • If the project exceeds obstruction standards, a NPH, (formerly known as a Determination of Presumed Hazard or DPH) is issued. The NPH recommends lowering the proposal to the height not exceeding obstruction standards (DNE height) and sometimes lists another height— the maximum “height for not exceeding” (HFNE), or occasionally called “no effects height” The FAA’s Obstruction Evaluation/Airport Airspace Analysis Process 99

(NEH), with respect to hazard criteria. The HFNE height may be noted if the proposal is in proximity to other proposals or existing structures the FAA has already studied, and the haz- ard limitations have already been calculated and/or if the FAA anticipates the structure pro- ponent would not accept the DNE height and will want the proposal to obtain a DNH at maximum feasible height. The NPH is temporary, with a 60-day expiration date. If no resolution is attempted within 60 days, the FAA terminates the case. If the structure proponent requires a favorable determi- nation from the FAA as part of the construction permit process, or for any other reason, the structure proponent must respond within 60 days. The NPH contains language specifically stating that the situation requires resolution, and that the NPH document does not imply FAA’s favorable acceptance of the proposal at any height. This is so that the NPH document will not be misconstrued as a favorable determination from the FAA, even if the structure proponent agrees to lower the proposed height to the DNE or HFNE elevations. When an NPH is issued, the project proponent has several resolution options: 1. The proponent may accede in writing to lower the proposed height of the structure so that it would not exceed obstruction standards (the DNE elevation). This routinely results in the FAA issuing a DNH. 2. The proponent may accede in writing to lower the height of the structure to the HFNE height, if one was indicated on the NPH. This routinely results in the FAA issuing of a DNH, with marking and lighting requirements. 3. The proponent may request in writing the FAA to perform further aeronautical study at the originally requested height. 4. The proponent may request in writing the FAA to perform further aeronautical study at a reduced height that is lower than the originally requested height but not as low as the height not exceeding obstruction standards, depending on a variety of factors. Further Aeronautical Study If the structure proponent requests further aeronautical study as described in #3 or #4, the FAA initiates the further aeronautical study process, a complex process which involves analyzing flight procedures, NAVAIDS, radar, and other factors in the airspace in the vicinity of the proposed structure. The objective of further aeronautical study is to determine whether the proposed struc- ture would have a substantial adverse affect to a significant amount of air traffic, and thereby constitute a hazard to air navigation. The further aeronautical study process will involve distribu- tion to other FAA lines of business and other interested agencies, and may take several months. Typical triggers of hazard status include the following: ✈ Height: the primary focus of this research; the object would be an obstacle that would affect published instrument procedures (TERPS and related criteria) and/or visual flight procedures. ✈ Electromagnetic interference: the object, due to its size, position, material composition, or electromagnetic transmissions, would block or distort electromagnetic signals to or from critical navigation aids, satellites, radar, or aircraft. ✈ Visual impediments: the object would block or otherwise interfere with FAA control tower line of sight, or would cause pilot or controller distraction due to glare, smoke, dazzling lights, sun reflection, or other factors. ✈ Wildlife attractants: the object, or more commonly, use, would attract birds or other wildlife that could jeopardize aircraft operations. The most common example is a garbage dump that would likely attract a large number of birds. 100 Understanding Airspace, Objects, and Their Effects on Airports

During the further aeronautical study phase, the FAA at its discretion may “circularize” the proposal under the Public Notice process. A Public Notice contains the basic data of the pro- posal and the amount by which it exceeds obstruction standards, and may contain affects to published instrument procedures if the FAA has calculated those in the early review. The Public Notice is posted on the publicly available portion of the FAA’s OE/AAA website, and can also be emailed or mailed to local airport sponsors, airlines, pilots’ associations, and other interested parties in the aviation community, at the FAA’s discretion. FAA OE/AAA website subscribers who have requested to be notified of proposals, determinations, and public notices in proxim- ity to specified airports will be automatically notified. Any interested stakeholder may submit comments by the due date as specified by the FAA, which generally falls 35 to 40 days after the issuance of Public Notice. Public Notice is the formal, and sometimes the only, opportunity for third-party stakeholders (i.e., not FAA or the structure proponent) to provide input in the OE/AAA process. The FAA must consider all comments of a significant aeronautical nature. At the conclusion of the further aeronautical study phase, the FAA will determine whether or not the proposed structure would constitute a hazard to air navigation. Issuance of Determination If no substantial adverse effects are identified in the further aeronautical study process, a DNH would be issued, with an 18-month expiration date. On the DNH letter, the FAA directs the pro- ponent to file supplemental FAA Form 7460-2, Notice of Actual Construction, in two parts: Part 1, at least 10 days prior to beginning construction; and Part 2, within 5 days after structure reaches its greatest height. In addition, the FAA may require a certified professional survey be performed on the finished structure as a contingency on a DNH. If the proposal exceeds obstruction stan- dards, marking and lighting requirements are noted as a contingency of the DNH, with reference to the latest FAA AC containing marking and lighting guidance (Currently, AC 70/7460-1). If the proposed structure is found to have substantial adverse effect, the FAA contacts the structure proponent to notify them of the results of the further aeronautical study; and gener- ally, proposes a maximum height not exceeding hazard standards (refined calculated HFNE). If the structure proponent accepts this height, a DNH can be issued for the negotiated height. If the structure proponent does not accept the negotiated height, a DOH to air navigation is issued. Alternatively, the structure proponent may request the FAA to bring about airspace changes in order to accommodate the proposal at the originally requested height or some other height that exceeds the FAA’s calculated HFNE. If the FAA considers the airspace changes may be fea- sible, the further aeronautical study process is restarted, with Public Notice issued indicating the proposed changes to airspace, flight procedures, and air traffic procedures that would be required if the structure were built as proposed. Stakeholders may comment on the new infor- mation and proposed airspace changes, and the further aeronautical study process is carried out again as described above. Acceptable changes to airspace are rare in practice, because (1) airspace procedures as designed are usually sub-optimal in some manner, developed around existing obstacles, and the introduction of new critical obstacles would further degrade them; and (2) changing airspace procedures in order to accommodate proposed structures sets the prece- dent that further changes could be implemented, which would lead to a gradual degradation of the safety, utility, and efficiency of the airspace surrounding airports. Although clearly undesirable from the standpoint of aviation stakeholders, proposed struc- tures that received a DOH are occasionally legally constructed. This can occur if, among other factors, the following conditions are met: (1) the local municipal authority having jurisdiction The FAA’s Obstruction Evaluation/Airport Airspace Analysis Process 101

issues a construction permit even if aware of the DOH; (2) the State, county, or other secondary authority having jurisdiction over airspace matters, if applicable, issues a construction permit or otherwise allows the structure even if aware of the DOH; (3) the sponsor(s) of affected nearby airport(s) are unable to convince local, State, and other authorities to limit the structure height, even if its presence in the airspace would degrade the safety and/or utility of the airport(s) to the point that Federal obligations and grant assurances would be violated; and (4) the structure pro- ponent is able to obtain any required hazard and/or liability insurance coverage, even if the insurance underwriter is aware of the DOH. Ultimately, it is up to the local community (municipal and State agencies, developers, airport owners, stakeholders, and the public) to decide the most appropriate compromises between the interests of airspace protection and land development. Petitions for Discretionary Review Within 30 days of the issuance of a final determination (a DNH or DOH), a petition for dis- cretionary review (an “appeal”) may be filed with the FAA Washington, DC Headquarters. A petition could be filed by the structure proponent in protest of a DOH, or by an aviation stake- holder in protest of a DNH. The Airspace and Rules Division (ATA-400) is responsible for pro- cessing petitions for discretionary review. A requested review may be granted or denied. If discretionary review is denied, the original determination will be made final. If discretionary review is granted, ATA-400 will carefully review the original case, and may request additional information from various stakeholders. The potential outcomes of discretionary review are that the original determination may be affirmed, revised, or reversed by FAA Headquarters. The FAA’s discretionary review decision is final. Actual Construction; Cataloguing and Distribution of Obstacle Data A DNH has an 18-month expiration date. Actual construction of the structure (foundations, framing, and not site work only) must be initiated prior to the expiration date in order for the DNH to become permanent. If actual construction cannot begin by this time, the structure pro- ponent can file for a one-time 18-month extension. If actual construction does not begin within the expiration date of the DNH or the extension, the DNH lapses, the FAA terminates the case, and the structure proponent must file a new Form 7460-1 in order to re-initiate analyses that would lead to a new DNH. When actual construction begins, the structure proponent is required to file Form 7460-2, Parts 1 and 2, as required on the DNH letter. Depending on criticality to airspace procedures, the FAA may request a certified survey of the completed structure be performed by a licensed civil engineer or surveyor. The structure owner is required to provide and perpetually maintain any mandatory obstruction marking and lighting. The FAA OES maintains and updates a list of all the proposed projects and projects for which the supplemental Form 7460-2 has been submitted. This information regarding man-made objects is periodically incorporated into the DOF maintained and updated by the FAA’s NACO. The DOF can be used internally by the FAA, and can be purchased by airlines, airports, and other vendors or consultants for use in obstacle evaluation, flight procedure design, and the like. Figure C.2 is a logic diagram depicting the OE/AAA process. 102 Understanding Airspace, Objects, and Their Effects on Airports

Figure C.2. The FAA’s obstruction evaluation/airport airspace analysis process. (continued on next page)

Figure C.2. Continued.