AC NO: 70/7460-1B DATE: 1 Oct 72
ADVISORY
CIRCULAR
DEPARTMENT OF TRANSPORTATION
FEDERAL AVIATION ADMINISTRATION SUBJECT: OBSTRUCTION MARKING AND LIGHTING PURPOSE. This advisory circular describes the FAA standards on obstruction marking and lighting and establishes the methods, procedures and equipment types for both aviation red and high intensity white obstruction lights.
CANCELLATION® This circular cancels and supersedes Advisory Circular Number 70/7460-1A, dated January 1972.
3. EXPLANATION OF REVISIONS. This circular updates Advisory Circular Number 70/7460-1A by making numerous editorial changes of a minor nature.
HOW TO OBTAIN THIS CIRCULAR. Obtain copies of this Advisory Circular Number 70/7460-1B, Obstruction Marking and Lighting, free of charge Washington, D. C. from the Department of Transportation, Distribution Unit, IAD-484.3, 20590.
Willin M Flener WILLIAM M. FLENER Director, Air Traffic Service Initiated by: AI-240
1 Oct 72 AC 70/7460-1B
TABLE OF CONTENTS Page No.
CHAPTER 1. INTRODUCTION 1
2. 1. Purpose Objective 1
3. Federal Communications Commission Specifications CHAPTER 2. GENERAL REQUIREMENTS 3
4. Application 3 Deviations and Modifications 3 CHAPTER 3. MARKING 5
6. Purpose
7. Colors
8. Types of Markers
9. Coloring CHAPTER 4. LIGHTING 11
10. Purpose 11
11. Location of Lighting 11
12. Qualities of Lighting 12
13. Operation of Obstruction Lighting 14
14. Special Conditions 18 CHAPTER 5. OBSTRUCTION MARKING AND LIGHTING EQUIPMENT 21
15. Paint 21
16. Lights and Associated Equipment 21 CHAPTER 6, STANDARDS FOR LIGHTING OBSTRUCTIONS TO AIR NAVIGATION WITH AVIATION RED OBSTRUCTION LIGHTS 25
17. Purpose 25
18. Application 25
19. Specifications 26 Page 1
1 Oct 72 AC 70/7460-1B CHAPTER 1, INTRODUCTION
1. PURPOSE. This advisory circular describes the FAA standards on obstruction marking and lighting and establishes the methods, procedures and equipment types as official Federal Aviation Administration policy.
2. OBJECTIVE. The Administrator of the FAA has the statutory responsibility for promoting safety in air commerce. In the light of this responsibility the FAA describes the standards in this publication as the most effective means of indicating the presence of obstructions to pilots.
3. FEDERAL COMMUNICATIONS COMMISSION SPECIFICATIONS. The specifications for obstruction marking and lighting antenna structures, contained in Subpart C of Part 17 of the Federal Communications Commission Rules and Regulations, are identical with the standards outlined in this publication for marking obstructions with bands of aviation surface orange and white color in accordance with Chapter 3 and for lighting obstructions in accordance with Chapter 6.
Chap. 1 Par. Page 1 (and 2)
1 Oct 72 AC 70/7460-1B CHAPTER 2. GENERAL REQUIREMENTS
4. APPLICATION.
2. Objects to be Marked and Lighted. When any object or portion thereof, either temporary or permanent, exceeds any standard for determining obstructions set forth in Part 77 of the Federal Aviation that object should be marked and lighted in accordance with the Regulations (14 CFR 77) and/or a height of 200 feet above site level will not impair safety to air navigation, applicable standards described herein, unless an FAA aeronautical study determines that the absence of such marking and/or lighting
b. Recommended Equipment. Recommended types of equipment and the guidelines for marking and lighting of obstructions are contained in the standards, specifications, and procedures outlined in this circular.
5. DEVIATIONS AND MODIFICATIONS. After an initial determination through and lighted, a further determination may be made on whether the application of the marking and lighting can be modified, or a deviation application of the two basic criteria, that an object should be marked from the standards can be concurred in, The final determination that may result in an FAA recommendation for a modified application of the marking and lighting, or a deviation from the standards must be based be effective to the extent that an acceptable level of safety is achieved. on an FAA study showing that the recommended marking and lighting would
2. Deviations. Deviations from the obstruction marking and lighting standards set forth in this publication should have the coordinated approval of the Director, Air Traffic Service, Some examples of deviations are changes in:
(1) Basic signals and intensity.
(2) Flashing rates.
(3) Dimensions of described color bands or rectangles,
(4) Colors prescribed, etc.
AC 70/7460-1B 1 Oct 72
b. Modifications. Modified applications of the standards may be recommended when, in the opinion of the FAA regional director or his designee, conducting the study, marking and lighting in accordance with the proposed modification would provide adequate are: protection for sir commerce. Some examples of modified applications
(1) The object may be located with reference to other objects or the contour of the ground so that the specific marking and/or lighting standards need be applied to only a portion of it.
(2) The object may be so removed from the general flow of air traffic or so conspicuous by its shape, size, or color that marking would serve no useful purpose.
(3) The object may present such a potential hazard that marking or lighting should be provided similar to that for an object of greater height or size.
(4) Other similar situations.
Page 4 Chap. 2 Par. 5
1 Oct 72 AC 70/7460-1B CHAPTER 3. MARKING PURPOSE. The purpose of marking a structure which may be an obstruction to air commerce is to warn airmen during the hours of daylight of its presence. To accomplish this objective, it may be necessary to color such an obstruction so that it will be visible from aircraft at any normal angle of approach, or to indicate its general definition and location by use of suitable markers or flags.
7. COLORS. Maximum visibility of an obstruction by contrast in colors can best be obtained by the use of aviation surface orange and white.
TYPES OF MARKERS. Markers of various types should be used to mark obstructions when it has been determined that it is impracticable to mark such obstructions by painting, or it has been determined that markers should be used to provide protection for air commerce in addition to that provided by the application of aviation surface orange and white colors.
Display. Markers should be displayed on or adjacent to the obstructions in conspicuous positions so as to retain the general definition of the obstruction and should be recognizable in clear air from a distance of at least 1,000 feet in all directions from which an aircraft is likely to approach the obstruction.
b. Shapes. Markers should be distinctively shaped so that they are not mistaken for markers employed to convey other information, and they mark is not increased. should be such that the hazard presented by the obstruction they Spherical Markers. Markers displayed on overhead wires should be spherical in shape with a diameter of not less than 20 inches. They may be of another shape, provided the projection of such type of marker on any vertical surface, normal to each direction from which an aircraft is likely to approach the obstruction, will not be less than that presented by the spherical type marker described above. At least one such marker should be displayed for each 150 feet, or fraction thereof, of the overall length of the overhead line. These markers should be placed at equal intervals not more than 150 feet apart with the top of each marker not below the level of the highest wire at the point marked, and should be colored as specified by paragraph 9, COLORING. The distance between markers on overhead wires located more than 15,000 feet from the reference point of the nearest landing area may be increased to a distance of not more than 600 feet.
Chap. 3 Par. 6 Page 5
AC 70/7460-1B 1 Oct 72
(2) has been determined that marking such obstructions by coloring or by spherical markers is technically impracticable. Flag Markers. Flags may be used to mark obstructions when it Display. The flags should be displayed around or on top of the obstruction or around its highest edge and should mark. When flags are used to mark extensive obstructions not increase the hazard presented by the obstruction they displayed at approximately 50-foot intervals. or groups of closely spaced obstructions, they should be
(b) Shapes, The flags should be rectangular in shape and have stiffeners to keep them from drooping in calm or light height that they will support the flags free of the ground, wind. The flag stakes should be of such strength and vegetation, or nearby surfaces.
(c) Color Patterns. Flags should be in one of the following patterns:
Solid color aviation surface orange not less than two feet on a side, 2 Iwo triangular sections, one of aviation surface orange form a rectangle not less than two feet on a side, and the other of aviation surface white, combined to 3 A checkerboard pattern of aviation surface orange and aviation surface white squares, each one foot plus or minus 10 percent on a side, combined to form a rectangle not less than three feet on a side.
9. COLORING. been developed for use by government agencies and private industry for luminance factors satisfy the specifications of the Federal standard in marking obstructions to air navigation. Orange or white enamel or reflective paint may be used for marking provided its chromaticity and paragraph 15.a. Paints and enamels of aviation surface orange and white have Page 6 Chap. 3 Par. 8
1 Oct 72 AC 70/7460-1B * General. The specifications of surface colors apply only to freshly colored surfaces. Colors used for surface markings usually change with time. While it is not feasible to require maintenance in accordance with strict mathematical limits, due diligence should be exercised to ensure that surfaces are renewed whenever the color Tolerance Chart. deviates from the limits of the FAA Aviation Surface Orange Color Deletion of Painting. If the smooth surface of the paint on the ladders, decks, and walkways of certain types of steel towers and similar structures presents a potential danger to maintenance personnel, such surfaces need not be painted.
However, the omission of paint should be restricted to actual surfaces the painting of which will endanger maintenance personnel, and care should be taken that the overall marking the painting is not reduced.
(2) Areas Where Applied. On skeletal-type structures paint should be applied to all surfaces of all parts (both inner and outer) of the framework.
b. Variations.
(1) plane has both dimensions less than five feet, should be colored aviation surface orange, Solid. An obstruction, the projection of which on any vertical Bands. Towers, poles, smokestacks and similar obstructions, as well as buildings of certain shapes and dimensions, having essentially unbroken surfaces, the projection of which on any vertical plane is five feet or more in one dimension, and is less than 15 feet in the other dimension, and any skeleta. ol smokestack-type obstruction having both dimensions five feet oi more, should be colored to show alternate bands of aviation surface orange and white, The bands should be perpendicular to the major axis of the obstruction, with the band at each end The widths of the bands should be equal and the width of each band should be approximately one-seventh of the length of the major axis of the obstruction, provided that each band shall have a width of not more than
(a) If the structure under study is a smokestack, skeletal structure, flagpole or similar object erected on top of a building, the combined height of the object and the supporting building should be considered the overall height to determine whether obstruction marking should be applied;
however, only the length of the major axis of the smokestack, skeletal structure, or flagpole in this situation determine the width of the color bands.
Chap. 3 Par. 9 Page 7
АС 70/7460-1B 1 Oct 72 (Б) Partly Shielded. If a smokestack, skeletal structure, pole or similar structure not erected on top of a building is located with reference to other objects or the contour of the ground so that marking need be applied to only a portion of it, the width of the applied bands should be determined by the length of the major axis of the complete structure and not of just the colored portion.
(с) Minimum Number of Bands. If a recommendation is made that portion of a structure, at least three colored bands, of a width determined by applying the "one-seventh rule" to the length of the major axis of the structure, should be displayed on that upper portion to ensure an orange-whiteorange pattern as a minimum color display.
* (d) Deletion, If flashing white high intensity obstruction lights are installed on a smokestack for day marking, no aviation surface orange and white stripes would be required.*
(3) Checkerboard Pattern, Water towers, grain elevators, gas holders, and similar obstructions, as well as buildings of certain shapes and dimensions, having essentially unbroken surfaces the projection of which on any vertical plane is 15 project dimene ione, vertical surfaces colored to show a checkerboard pattern of feet or more in both dimensions, should have their top and alternate rectangles of aviation surface orange and white. it is technically impracticable to color the roof of a building If to show alternate rectangles of aviation surface orange and white, such roof may be colored aviation surface orange, The sides of the rectangles should measure not less than five feet nor more than 20 feet. The rectangles at the corners of surfaces should be colored aviation surface orange.
Page S Chap. 3 p--
1 Oct 72 AC 70/7460-1B * (4) Beachball Pattern. Water towers with a single circular standpipe support may be colored in the beachball striped pattern.
The storage tank should be colored to show alternate stripes of aviation surface orange and white. The stripes should extend from the top center of the tank to its supporting standpipe.
The width of the stripes should be equal and the width of each band at the greatest girth of the tank should be not less than five feet nor more than 15 feet. If it is desirable to paint the name of the community on the side of the tank, the stripe pattern may be broken for a sufficient distance to serve this feet. purpose. This open area should have a maximum height of three C. Exceptions.
(1) Combined Patterns. If a part of a water tower, gas holder, building, or similar obstruction consists of a skeletal-type construction, that portion of the obstruction should be colored with alternate bands of aviation surface orange and white as specified for towers, poles, smokestacks and similar obstructions. In this case, if the portion of the obstruction which is to be colored to show a checkerboard pattern of alternate rectangles of aviation surface orange and white, has any surfaces the projection of which on any vertical plane is less than 15 feet in either dimension, the alternate rectangles of aviation surface orange and white may have dimensions of less than five feet on a side, provided their dimensions remain as close as practicable to the minimum five feet specified for coloring by the checkerboard pattern,
(2) Bands on Certain Structures. If the size and shape of water towers, grain elevators, gas holders, and similar obstructions come within the dimensions set forth under the specification for coloring by bands, or if their type of construction does not permit coloring by the checkerboard pattern described in b(3) above, then such obstructions should be colored by bands as specified for towers, poles, smokestacks, and similar obstructions. Where this method of coloring is employed, the top aviation surface orange band should be continued from the vertical surface so as to cover the entire top of the obstruction.
Chap. 3 Par. 9 Page 9
AC 70/7460-1B 1 Oct 72
(3) of aviation surface orange and white covering the spherical shape may be modified to fit the particular shape of the Spherical Shaped Structures. If a part, or all, of certain shape does not permit the exact application of the checkerboard pattern of coloring, then the shape of the alternate rectangles obstructions such as water towers and gas holders of spherical structural surface, provided the dimensions of these modified checkerboard pattern. limits set forth in the specifications for coloring by the rectangles remain to the extent practicable within the dimensional
(4) Limited Pattern. If certain obstructions such as gas holders of the checkerboard pattern of coloring may be limited to the of the checkerboard pattern of coloring to the complete outer surface of the structure would be impracticable, the application and grain elevators are of such large size that the application protection for air navigation. upper one-third of the structure, provided the aeronautical study indicates that the modified marking will provide adequate
d. Special.
Marking of Vehicles. Vehicles customarily used on landing areas should be marked in accordance with the provisions of Advisory Circular 150/5210-5, Painting, Marking and lighting of Vehicles
(2) Buildings or Similar Obstructions. When the upper portion of a building or similar extensive obstruction projects above an airport imaginary surface, as described in Part 77 of the Federal Aviation Regulations, the point or edge of it highest in relation to the airport imaginary surface should be regarded as the "top of the obstruction." In certain cases, however, such as when the airport imaginary surface concerned is an approach or transition surface, i,e., sloping, this point or edge highest in relation to the airport referenced surface may not be the highest point or edge above a horizontal plane passing of the object, the upper parts of which are higher above a horizontal plane passing through the base of the object than through the base of the object. In such cases, those portions should also be obstruction marked. the upper part considered as the "top of the obstruction," Hazard Areas. The FAA may recommend appropriate marking in an area where towers, poles, and similar obstructions are so grouped as to present a common hazard to air commerce; where the hazard of a particular obstruction is increased by guy wires or other appurtenances; or, where an invisible hazard to aircraft Page 10 Chap. 3 Par. 9
1 Oct 72 AC 70/7460-1B CHAPTER 4. LIGHTING PURPOSE. The purpose of lighting an object that may be an obstruction to air navigation is to warn airmen of its presence during the hours of darkness and during periods of limited daytime light intensity and meteorological visibility. To accomplish this objective, it is necessary to display lighting on the obstruction of sufficient intensity, and in such a manner, that it will attract the attention of the pilot of any airplane that is approaching the obstruction from any angle while at obstruction. any altitude up to 1,500 feet above the uppermost point on the
11. LOCATION OF LIGHTING. The following factors should be considered when determining the placement of obstruction lights on a structure as specified in Chapters 6, 7 and 8:
Adjacent Structures, The mean elevation of the tops of the buildings in closely built up areas may be used as the equivalent of the ground level when determining the proper amount of obstruction lighting necessary to adequately mark an obstruction, Top Lighting. The top light, or lights, displayed on an obstruction should be installed so as to mark the points or edges of the obstruction highest in relation to an airport imaginary surface, as described in Part 77 of the Federal Aviation Regulations, except or lights, should be installed on the points or edges of the that when no airport imaginary surface is involved, such top light, obstruction highest in relation to the ground, or water if so situated. If two or more edges of an extended obstruction located near any landing and takeoff area of an airport are of the same height, an obstruction lighting is to be displayed on only one of lighted. the edges, the edge nearest the landing and takeoff area should be
c. Shielded Lights. If a light, or lights, which is installed on an obstruction is shielded in any direction by an adjacent object, additional lights should be mounted on that object in such a way as to retain the general definition of the obstruction, the shielded definition of the obstruction. light, or lights, being omitted if it does not contribute to the Chap. 4 Par. 10 Page 11