A Comparative Study of FAA and ICAO Obstacle Clearance Regulations

The safety of aircraft operations in the vicinity of an airport is dependent on adequate clearance being provided between the aircraft and any ground obstacles. The Federal Aviation Administration (FAA) and International Civil Aviation Organization (ICAO) are two regulatory bodies that prescribe obstacle clearance standards for airports. The FAA defines U.S. standards, while ICAO defines international standards that have been adopted by a number of countries around the world. The purpose of this paper is to provide an understanding of the differences and similarities of both the FAA and ICAO obstacle clearance regulations, through a comparison of their regulatory standards. The FAA has three sets of regulations that define obstacle clearance requirements: Code of Federal Regulation (14 CFR) Part 77 "Objects Affecting Navigable Airspace;" Advisory Circular (AC) 150/5300-13 "Runway Design;" and Terminal Instrument Procedures (TERPS) 8260.3B. By contrast, ICAO has two sets of regulations that refer to obstacle clearance: Annex 14, Volume 1, Aerodrome Design; and Procedures for Air Navigation Services (PANS-OPS) Document 8168, Volume 1. Specifically, the comparative focus of this paper is on the airport imaginary surfaces defined in CFR Part 77 and Annex 14, the obstacle-free zones defined in AC 150/5300-13 and Annex 14, and the circling and instrument landing system (ILS) obstacle clearances defined in TERPS and PANS-OPS. To illustrate the comparative advantages and disadvantages of the FAA and ICAO regulations, the obstacle clearance surface areas prescribed by the regulations will be assessed for three different runway sizes: small, visual only runway (1000 m x 20 m); medium, non-precision approach runway (1500 m x 30 m); and a large, precision approach runway (2500 m x 60 m). Furthermore, to illustrate the adoption of ICAO Annex 14 obstacle clearance standards by another country, the airport imaginary surfaces as defined by the Civil Aviation Authority of New Zealand (CAA(NZ)) will also be compared to the FAA's CFR Part 77 and ICAO Annex 14 imaginary surfaces. The CAA(NZ) standards are defined in AC 139-06A "Aerodrome Design." The report has been designed so that a reader unfamiliar with the topic can be familiarized with general terminology in Section 2, while those conversant with the topic can advance immediately to Section 3. In Section 3, the FAA's Part 77 "airport imaginary surface" standards and ICAO's Annex 14 "obstacle limitation surface" standards are compared. In Section 4, the obstacle-free zone regulations as defined in AC 150/5300-13 are contrasted to similar regulations defined by ICAO in Annex 14, and in Section 5 the circling and ILS obstacle clearance standards defined in TERPS and PANS-OPS are compared. Section 6 provides a comparative summary of the obstacle clearance surface areas for the three example runways, based on the standards defined in Sections 3 through 5. Finally, it should be noted that System Internationale (S.I.) metric units have primarily been used for the comparison of dimensions. The factor used to convert non-S.I. units to S.I. units is: 1 ft = 0.3048 m, with the result then rounded to the nearest 10 m.


  • English

Media Info

  • Media Type: Digital/other
  • Edition: Research Report
  • Features: Appendices; Figures; References; Tables;
  • Pagination: 55p

Subject/Index Terms

Filing Info

  • Accession Number: 01708700
  • Record Type: Publication
  • Report/Paper Numbers: ARC-701
  • Files: TRIS
  • Created Date: Jun 25 2019 6:04PM