Obstruction Marking and Lighting.pdf

10/29/2024 AC 70/7460-1M, CHG 1

Advisory Circular

Obstruction Marking and Lighting Date: 10/29/2024

Initiated By: AJV-P13

U.S. Department Circular of Transportation Federal Aviation Administration

Date: 11/16/2020 Subject: Obstruction Marking and Lighting AC No. 70/7460-1M Initiated By: AJV-P13

Purpose.

This Advisory Circular (AC) describes the Federal Aviation Administration’s standards for marking and lighting structures to promote aviation safety.

Cancellation.

AC 70/7460-1L, change 2, Obstruction Marking and Lighting, dated August 2018 is cancelled by this version.

Effective Date.

This AC is effective November 16, 2020.

Related Documents.

Title 14 of the Code of Federal Regulations Part 77 describes the standards used relative to objects in the navigable airspace and specifies the requirements for notice to the Administrator of certain proposed construction or alteration.

Federal Communications Commission (FCC) specifications are contained in Part 17 of the FCC Rules and Regulations.

Principal Changes.

This circular contains numerous editorial changes. Major changes are listed below.

a. Page 2, Addition of Note. The FAA has changed specifications for light emitting diode (LED)-based red obstruction lights to make them visible to pilots using certain night vision goggle systems. Effective with the implementation of this change in FAA AC 150/5345-43, Specification for Obstruction Lighting Equipment, manufacturers will be required to meet the new specification for certified red LED-based obstruction lights.

b. Page 6, Removed paragraph 2.8, Obstruction Height Definition. Structures lower than 499 feet AGL can be considered obstructions. As written, the paragraph caused confusion and was deleted.

c. Informational paragraphs are added regarding the change to manufacturing standards for LED-based red obstruction lights compatibility with night vision goggle systems and maintaining conspicuity to avoid misinterpretation when replacing lights.

d. Reorganized information in Chapter 11, Marking and Lighting of Catenary and Catenary Support Structures and chapter 13, Marking and Lighting Wind Turbines.

e. Reorganized chapters by subject matter and figures in Pages A-1 to A-29, as well as minor grammatical changes.

ii

f. Added Chapter 14, Marking and Lighting Temporary Structures and associated figures in the Appendix, Figures A-31 through A-33.

g. Added Figure 22, Catenary Markers - Line Spacing (Adjacent Lines Within 200 feet (60.96 m) or Less.

h. Added Figure 30, Wind Turbine Lighting During Construction.

Federal Aviation Administration Manager, Policy Assurance Attention: AJV-P13 600 Independence Avenue, S.W. Washington, DC 20591

KAREN L

CHIODINI

Digitally signed by

KAREN L CHIODINI

Date: 2020.11.14

12:21:32 -05'00'

Karen Chiodini, Director (A) Policy, AJV-P

Mission Support Services Federal Aviation Administration iii https://2020.11.14 iv

Circular

Subject: Obstruction Marking and Lighting Date: 10/29/24 Initiated By: AJV-P13

AC No: 70/7460-1M, Change 1

Purpose.

This Advisory Circular (AC) describes the Federal Aviation Administration’s standards for marking and lighting structures to promote aviation safety. The contents of this document do not have the force and effect of law and are not meant to bind the public in any way, and the document is intended only to provide information to the public regarding existing requirements under the law or agency policies.

Audience.

This Advisory Circular applies to structure Sponsors, and serves as a reference tool for the Mission Support Services, Obstruction Evaluation Group and Office of Airports.

Effective Date.

This AC is effective October 29, 2024.

Related Documents.

a. Title 14 of the Code of Federal Regulations Part 77 describes the standards used relative to objects in the navigable airspace and specifies the requirements for notice to the Administrator of certain proposed construction or alteration.

b. Federal Communications Commission (FCC) specifications are contained in Parts 17 and 47 of the FCC Rules and Regulations.

c. Sponsors are required to contact the United States Coast Guard (USCG) for prior approval for the lighting of bridges according to 33 CFR 118.

Principal Changes.

This change is to update or correct information and modify standards to include new methods of marking structures and remove the use of steady-burning lights on tower structures. The change also clarifies information regarding modifications and deviations; updates verbiage to reflect the non-regulatory nature of the advisory circular and Meteorological Evaluation Tower name; as well as numerous editorial and formatting updates. Information regarding the major changes is listed below.

a. Page 1, Chapter 1, Paragraph 1.5. The information regarding modifications and deviations is updated to clearly define the meaning of each, as well as how they are requested by Sponsors and analyzed by the FAA.

b. Page 10, Chapter 2, Paragraph 2.7. The name of Meteorological Evaluation Towers is changed to meteorological towers. There is no abbreviation for the title of Meteorological Tower(s), so the use of “MET” for these structures is removed.

c. Page 53, Chapter 15, Paragraph 15.2.2 item 2. and throughout the document. The FAA has approved the use of alternative methods of marking structures, vinyl wrapping and powder coating, in addition to painting. This change adds information regarding the marking standards for the use of these methods. Additionally, due to these new marking methods for structures, paint is no longer the sole source and the term “marking” has replaced “painting” as appropriate throughout the AC.

d. Flashing side lights have replaced steady burning lights to avoid avian confusion and provide a level of protection to reduce deaths. Existing structures lit with steady burning lighting is acceptable at this time. However, as these lights necessitate replacement, they should be upgraded to flashing lights. All new construction requires the installation of flashing lights.

e. In paragraphs 7.6, 7.7. and 9.5 corrected the alphanumeric lighting type to reflect medium-intensity lighting.

f. The informational paragraph in Appendix B has been updated to clearly reflect the information as the application of data from Table-B and Figure B-1 to calculate pilot visibility of structures.

g. Addition of Advisory Circular Feedback page (last page).

h. Throughout the document, verbiage has been updated to reflect the non-regulatory nature of an advisory circular. Examples include changing the use of the word “must” to “should” and “requirements” to “recommendations” or “standards” as appropriate.

i. Editorial/format changes throughout the document were made where necessary, including Appendix A.

Application The FAA recommends the guidelines and standards in this AC for determining the proper way to light and mark obstructions affecting navigable airspace. This AC does not constitute a regulation and, in general, is not mandatory. However, a sponsor proposing any type of construction or alteration of a structure that may affect the National Airspace System (NAS) is required under the provisions of Title 14 Code of Federal Regulations to notify the FAA by completing the Notice of Proposed Construction or Alteration form (FAA Form 7460-1).

If you have suggestions for improving this AC, you may use the Advisory Circular Feedback Form on the last page of this document.

Federal Aviation Administration 600 Independence Avenue, S.W., Attention: AJV-P13 Washington, DC 20597-5580

Michael Beckles Director, Policy, AJV-P Mission Support Services | Air Traffic Organization Federal Aviation Administration v

Table of Contents

Paragraph Page

Chapter 1. ADMINISTRATIVE AND GENERAL PROCEDURES

1.1 Reporting Requirements

1.2 Preconstruction Notice

1.3 FAA Acknowledgement

1.4 Supplemental Notice Requirement

1.5 Modifications and Deviations

1.6 Additional Notification

Chapter 2. GENERAL

2.1 Structures to be Marked and Lighted

2.2 Guyed Structures

2.3 Marking and Lighting Equipment

2.4 Light Failure Notification

2.5 Notification of Restoration

2.6 Federal Communications Commission (FCC) Requirement

2.7 Voluntary Marking of Meteorological Towers Less Than 200 Feet

(60.96 m) AGL

Chapter 3. MARKING GUIDELINES

3.1 Purpose

3.2 Marking Colors

3.3 Marking Standards

3.4 Marking Patterns

Table 3-1: Structure Height to Bandwidth Ratio

3.5 Unlighted Markers

3.6 Flag Markers

3.7 Omission or Alternatives to Marking

3.8 Unusual Complexities

Chapter 4. LIGHTING GUIDELINES

4.1 Purpose

4.2 Standards

4.3 Lighting Systems

Paragraph Page

4.4 Inspection, Repair, and Maintenance

4.5 Nonstandard Lights

4.6 Placement Factors

4.7 Monitoring Obstruction Lights

4.8 Ice Shields

4.9 Light Shields

4.10 Distractions

Chapter 5. RED OBSTRUCTION LIGHT SYSTEM

5.1 Purpose

5.2 Standards

5.3 Control Device

5.4 Alternate Method of Displaying Obstruction Lights

5.5 Poles, Towers, and Similar Skeletal Structures

5.6 Chimneys, Flare Stacks, and Similar Solid Structures (except Hyperbolic

Cooling Towers)

5.7 Prominent Buildings, Bridges, and Similar Extensive Obstructions

5.8 Group of Obstructions

Chapter 6. MEDIUM INTENSITY FLASHING WHITE OBSTRUCTION LIGHT

SYSTEMS

6.1 Purpose

6.2 Standards

6.3 Control Device

6.4 Radio and Television Towers and Similar Skeletal Structures

6.5 Chimneys, Flare Stacks, and Similar Solid Structures

6.6 Prominent Buildings and Similar Extensive Obstructions

6.7 Group of Obstructions

6.8 Special Cases

Chapter 7. HIGH INTENSITY FLASHING WHITE OBSTRUCTION LIGHT

SYSTEMS

7.1 Purpose

7.2 Standards

Paragraph Page

7.3 Control Device

7.4 Units per Level

7.5 Installation Guidance

Table 7-1 Light Unit Elevation Above the Horizontal

7.6 Radio and Television Towers and Similar Skeletal Structures

7.7 Antenna or Similar Appurtenance Light

7.8 Chimneys, Flare Stacks, and Similar Solid Structures

7.9 Prominent Buildings and Similar Extensive Obstructions

7.10 Hyperbolic Cooling Towers

7.11 Special Cases

Chapter 8. DUAL LIGHTING WITH RED/MEDIUM INTENSITY FLASHING WHITE

LIGHT SYSTEMS

8.1 Purpose

8.2 Installation

8.3 Operation

8.4 Control Device

8.5 Antenna or Similar Appurtenance Light

8.6 Mounting Lights

8.7 Omission of Marking

Chapter 9. DUAL LIGHTING WITH RED/HIGH-INTENSITY FLASHING WHITE

LIGHT SYSTEMS

9.1 Purpose

9.2 Installation

9.3 Operation

9.4 Control Device

9.5 Antenna or Similar Appurtenance Light

9.6 Omission of Marking

Chapter 10. AIRCRAFT DETECTION LIGHTING SYSTEMS

10.1 Purpose

10.2 General Standards

Chapter 11. MARKING AND LIGHTING OF CATENARY AND CATENARY

SUPPORT STRUCTURES

11.1 Purpose

11.2 Lighted Spherical Markers

11.3 Catenary Marking Standards

11.4 Catenary Lighting Standards

11.5 Control Device

11.6 Area Surrounding Catenary Wire Support Structures

11.7 Three or More Catenary Wire Support Structures

Chapter 12. MARKING AND LIGHTING MOORED BALLOONS AND KITES

12.1 Purpose

12.2 Standards

12.3 Marking

12.4 Purpose

12.5 Operational Characteristics

Chapter 13. MARKING AND LIGHTING WIND TURBINES

13.1 Purpose

13.2 General Standards

13.3 Wind Turbine Configurations

13.4 Marking Standards

Table 13-1. Wind Turbine Marking Standard Colors

13.5 Lighting Standards

13.6 Wind Turbines Above 499 Feet (152.10 m)

13.7 Wind Turbines at or Above 699 Feet (213.36 m)

13.8 Lighting of Wind Turbines During Construction Phase

13.9 Lighting and Marking of Airborne Wind Turbines

13.10 Lighting and Marking of Offshore Wind Turbines

Chapter 14. MARKING AND LIGHTING TEMPORARY STRUCTURES

14.1 Purpose

14.2 General Standards

14.3 Marking Standards

14.4 Lighting Standards

14.5 Operational Characteristics

Chapter 15. MARKING AND LIGHTING EQUIPMENT AND INFORMATION

15.1 Purpose

15.2 Marking Standard

Table 15-1: Aerospace Material Specification Standard, SAE AMSSTD595A

15.3 Availability of Specifications and Advisory Circulars

15.4 Lights and Associated Equipment Standards

15.5 Availability of Military Specifications

APPENDIX A. SPECIFICATIONS FOR OBSTRUCTION LIGHTING EQUIPMENT

CLASSIFICATION .............................................................................................................. A-1

Figure A-3. Marking and Lighting of Water Towers, Storage Tanks, and Similar

Figure A-7. Dual Lighting of Poles, Towers, and Similar Structures/Lighting and

Figure A-13. High-Intensity White Obstruction Light Standards (FAA Style B)—

Figure A-14. High-Intensity White Obstruction Light Standards (FAA Style C)—

Table A-1: FAA-Approved Obstruction Lighting Fixtures .................................................. A-1 Figure A-1. Meteorological Tower Marking Standards (Monopole Structure).................... A-2 Figure A-2. Meteorological Tower Marking Standards (Guyed Structure) ......................... A-3

Structures ..................................................................................................................... A-4 Figure A-4. Marking and Lighting of Water Towers and Similar Structures....................... A-5 Figure A-5. Marking a Single Pedestal Water Tower Using the Teardrop Pattern .............. A-6 Figure A-6. Red Obstruction Light Standards (FAA Style A) ............................................. A-8

Painting of Chimneys................................................................................................... A-8 Figure A-8. Bridge Lighting ................................................................................................. A-9 Figure A-9. Medium-Intensity White Obstruction Light Standards (FAA Style D) .......... A-10 Figure A-10. Lighting of Chimneys, Flare Stacks, or Similar Solid Structures ................. A-11 Figure A-11. Lighting Adjacent Structures—Light Level Adjustment .............................. A-12 Figure A-12. Lighting Adjacent Structures ........................................................................ A-13

With Appurtenance 40 Feet or Less........................................................................... A-14

With Appurtenance Over 40 Feet High ..................................................................... A-15 Figure A-15. Lighting Hyperbolic Cooling Tower............................................................. A-16 Figure A-16. Medium-Intensity Dual Obstruction Light Standards (FAA Style E)........... A-17

Figure A-17. Medium-Intensity Lighting—Establishing the Location of Top Beacons ...................................................................................................................... A-18

Figure A-18. High-Intensity Dual Obstruction Light Standards (FAA Style F)—

Figure A-19. High-Intensity Dual Obstruction Light Standards (FAA Style G)—

Figure A-22. Catenary Markers – Line Spacing (Adjacent Lines Within 200 Feet

With Appurtenance Over 40 Feet High ..................................................................... A-19

With Appurtenance 40 Feet or Less........................................................................... A-20 Figure A-20. Aircraft Detection Lighting System (sample coverage map)........................ A-21 Figure A-21. Catenary Unlighted Markers (less than 69 kV)............................................. A-22

(60.96 m) or Less)...................................................................................................... A-23 Figure A-23. Catenary Markers - Line Spacing (Adjacent Lines Greater Than 200

Feet (60.96 m) Away) ................................................................................................ A-24 Figure A-24. Catenary Lighted Markers – Used in Conjunction with Unlighted

Markers (69 kV or greater) ........................................................................................ A-25 Figure A-25. Catenary Obstruction Lighting...................................................................... A-26 Figure A-26. Wind Turbine Lighting Configurations......................................................... A-27 Figure A-27. Lighting and Marking of Wind Turbines – Paint Schemes........................... A-28 Figure A-28. Wind Turbine Lighting and Marking in Snow Prone Areas (Optional) ....... A-29 Figure A-29. Wind Turbine Lighting.................................................................................. A-30 Figure A-30. Marking and Lighting of Turbines During Construction.............................. A-31 Figure A-31. Crawler Crane Marking and Lighting ........................................................... A-32 Figure A-32. Tower Crane Marking and Lighting.............................................................. A-33 Figure A-33. Container Crane Marking and Lighting ........................................................ A-34

APPENDIX B. MISCELLANEOUS...........................................................................................B-1 B.1 Rationale for Obstruction Light Intensities. ..................................................................B-1 B.2 Distance Versus Intensities. .............................................................................................B-1 Table B-1. Distance and Intensity..........................................................................................B-1 Figure B-1. Acquisition Distance Calculation .......................................................................B-2 B.3 Application....................................................................................................................B-2 B.4 Definitions.....................................................................................................................B-3

APPENDIX C. ACRONYMS .....................................................................................................C-1

APPENDIX D. ADVISORY CIRCULAR FEEDBACK FORM .............................................. D-1

10/29/2024 AC 70/7640-1M, CHG 1

CHAPTER 1. ADMINISTRATIVE AND GENERAL PROCEDURES

1.1 Reporting Requirements.

A Sponsor proposing any type of construction or alteration of a structure that may affect the National Airspace System (NAS) as required under the provisions of Code of Federal Regulations (CFR), Title 14, Aeronautics and Space, Part 77, Safe, Efficient Use, and Preservation of the Navigable Airspace (14 CFR, Part 77), must notify the Federal Aviation Administration (FAA) by completing the FAA Form 7460-1, Notice of Proposed Construction or Alteration.

This form should be filed electronically at https://oeaaa.faa.gov. The website includes the FAA Notice Criteria Tool for Sponsors use to determine if the structure exceeds criteria threshold and requires a notice to be filed.

1.2 Preconstruction Notice.

The notice must be submitted:

1. At least 45 days prior to the date of proposed construction or alteration is to begin.

2. On or before the date an application for a construction permit is filed with the

Federal Communications Commission (FCC). The FCC advises its applicants to file with the FAA well in advance of the 45-day period to expedite FCC processing.

1.3 FAA Acknowledgement.

The FAA will acknowledge, electronically, each FAA Form 7460-1 notice received.

1.4 Supplemental Notice Requirement.

1.4.1 If required, the FAA will include a statement requiring the filing of FAA Form 7460-2, Notice of Actual Construction or Alteration, on the determination. All FAA Forms 7460-2 should be filed electronically at https://oeaaa.faa.gov.

1.4.2 FAA Form 7460-2, Part 1, must be submitted to the FAA at least ten days prior to starting the actual construction or alteration of a structure. The FAA Form 7460-2, Part 2, completed within five days after the structure has reached its greatest height.

1.4.3 In addition, notification of dismantlement or abandonment of construction must be submitted to the FAA using the supplemental notice FAA Form 7460-2.

Note: Notification as required in the determination is critical to aviation safety.

1.5 Modifications and Deviations.

Requests for modification or deviation from the standards outlined in this Advisory Circular (AC) should be submitted to the FAA Obstruction Evaluation Group (OEG) by submitting FAA Form 7460-1, Notice of Proposed Construction or Alteration, to https://oeaaa.faa.gov./ https://oeaaa.faa.gov/ determine the potential effect on aviation safety. The Sponsor is responsible for adhering to approved marking and/or lighting limitations, and recommendations given, and should notify the FAA and FCC (for those structures regulated by the FCC) prior to making any changes, such as removal of marking and/or lighting.

1.5.1 Modifications.

A Sponsor may request a modification from the marking and lighting recommendations contained in a determination to the OEG to use alternative methods or configurations from the AC standards. Requests received for any changes after a determination has been issued will require a new aeronautical study and may result in a modified determination, including updated marking and/or lighting recommendations. If the FAA issues a modification from the marking or lighting requirements prior to the implementation of the changes, the Sponsor may also be required to notify the FCC.

Some examples of modifications are as follows:

1. Marking and/or lighting only a portion of an object. The object may be located with respect to other objects or terrain that only a portion of it needs to be marked and/or lighted.

2. No marking and/or lighting. The object may be located with respect to other objects or terrain, removed from the general flow of air traffic, or may be so conspicuous by its shape, size, or color that marking or lighting would serve no useful purpose.

3. Voluntary marking and/or lighting. The object may be located with respect to other objects or terrain that the Sponsor feels increased conspicuity would better serve aviation safety. Sponsors who desire to voluntarily mark and/or light their structure should do so in accordance with this AC.

4. Marking or lighting an object in accordance with the standards for an object of greater height or size. The object may present such an extraordinary hazard potential that higher standards may be recommended for increased conspicuity to ensure aviation safety.

The FAA strongly recommends that Sponsors become familiar with the different types of lighting systems and specifically request the type of lighting system desired when submitting FAA Form 7460-1. Information regarding types of lighting systems is provided in Chapters 5 - 10, and specifications regarding lighting equipment classifications in Appendix A, Table A-1, in this AC. While the FAA will make an effort to accommodate the structure Sponsor’s request, Sponsors should also request information from system manufacturers to determine which system best meets their needs based on purpose, installation, and maintenance costs.

1.5.2 `Deviations.

The assigned Obstruction Evaluation Specialist will forward the request to the FAA Airport Safety Research and Development Section to conduct analysis and testing of the proposed deviation(s) for approval of use or to initiate testing in cooperation with the FAA. Proposed requests to deviate from current marking and lighting standards for research and development to introduce new technology or improve current standards.

The FAA will perform a safety assessment for use in the NAS and may request status reports and/or additional information as needed. If at any time the FAA determines the study has created an unsafe condition, the deviation request may be terminated.

Research and development testing is independent of the aeronautical study process and generally requires a more lengthy analysis period for evaluation by the FAA for aviation safety. When testing is complete and the FAA concludes its review, the Sponsor will be notified of the determination. Examples of deviations that may be considered include, but are not limited to alternative painting schemes, colors/types of lights, basic signals and intensity of lights, night/day lighting combinations, and flash rate.

1.6 Additional Notification.

Proper authorization and annotations of obstruction marking and lighting may require the Sponsor to provide notice to the FCC prior to making any change to the submitted information which the FAA based its determination. This includes modification, deviation, or optional upgrade to white lighting on structure, which may be subject to inspection and enforcement of marking and lighting requirements by the FCC. FCC forms and bulletins can be obtained from the FCC’s National Call Center at 1-888- CALL-FCC (1-888-225-5322) or online at: Forms | Federal Communications Commission (fcc.gov) and Antenna Structure Registration (ASR) - Forms | Federal Communications Commission (fcc.gov). Additionally, upon completion of the actual change complete the Supplemental Notice (FAA Form 7460-2) at the https://oeaaa.faa.gov website.

https://www.fcc.gov/licensing-databases/forms https://www.fcc.gov/licensing-databases/forms https://www.fcc.gov/wireless/support/antenna-structure-registration-asr-resources/antenna-structure-registration-asr-1 https://www.fcc.gov/wireless/support/antenna-structure-registration-asr-resources/antenna-structure-registration-asr-1 https://oeaaa.faa.gov/

CHAPTER 2. GENERAL

2.1 Structures to be Marked and Lighted

Any temporary or permanent structure, including all appurtenances, that exceeds any obstruction standard contained in 14 CFR Part 77 or an overall height of 200 feet (60.96

m) above ground level (AGL) should be marked and/or lighted. However, an FAA aeronautical study may reveal that the absence of marking and/or lighting will not impair aviation safety. Conversely, the object may present such an extraordinary hazard potential that higher standards may be recommended for increased conspicuity to ensure aviation safety. Recommendations for marking and/or lighting structures can vary, depending on terrain features, weather patterns, geographic location, number of structures, and overall design layout. The FAA may also recommend marking and/or lighting a structure that does not exceed 200 feet (60.96 m) AGL or 14 CFR Part 77 standards because of its particular location. The marking and lighting configurations are illustrated in Appendix A.

2.2 Guyed Structures

Properly maintained marking and lighting are important for increased conspicuity because the guys of a structure are difficult to see until the aircraft is dangerously close.

Section 91.119 of 14 CFR requires pilots, when operating over other than congested areas, to remain at least 500 feet (152.40 m) from man-made structures. Therefore, the tower must be cleared by 2,000 feet (609.60 m) horizontally to avoid all guy wires. The guys of a 2,000-foot (609.60 m) skeletal tower are anchored between 1,600 feet (487.68

m) and 2,000 feet (609.60 m) from the base of the structure. This places a portion of the guys 1,500 feet (457.20 m) from the tower at a height of between 125 feet (38.10 m) and 500 feet (152.40 m) AGL.

2.3 Marking and Lighting Equipment

Considerable effort and research were expended to determine the minimum marking and lighting systems and quality of materials that will produce an acceptable level of aviation safety. The FAA will recommend only those marking and lighting systems that meet established technical standards and commercial outside lighting should not be used in lieu of FAA recommended marking and/or lighting. While additional lights may be desirable to identify an obstruction to air navigation, and may on occasion be recommended, the FAA will recommend minimum standards in the interest of safety, economy, and related concerns. Therefore, to provide an adequate level of safety, obstruction lighting systems should be installed, operated, and maintained in accordance with the recommended standards herein. Chapter 15 contains descriptions of FAA-approved obstruction marking and lighting equipment and information referred to in this AC.

2.4 Light Failure Notification

Sponsors should consider that conspicuity is achieved only when all recommended lights are working. Partial equipment outages decrease the margin of safety. Any flashing light outage should be REPORTED IMMEDIATELY AND corrected as soon as possible. Failure of steady-burning side or intermediate lights should be corrected as soon as possible, but notification is not required.

Manufacturers are required to meet FAA specifications for certified red LED-based obstruction lights to make them visible to pilots using certain night vision goggle systems. FAA AC 150/5345-43, Specification for Obstruction Lighting Equipment, specification ensures the light is visible to pilots operating with night vision goggles, to avoid the risk of a pilot misinterpreting the tower height if a legacy intermediate-level light is replaced with one that meets the specification unless the top light meets the new specification as well. Therefore, if a legacy specification intermediate-level LED-based light is replaced with a light that meets the specifications, then the top-level light(s) on the obstruction should also be updated to ensure the entire obstruction is visible during the use of night vision goggles.

2.4.1 Any failure or malfunction that lasts more than thirty (30) minutes and affects a top light, flashing obstruction light regardless of its position, wind turbine lighting fixture, or wind turbine synchronization should be reported immediately by calling Outage Reporting and Notice to Air Missions (NOTAM) at 877-487-6867, or in Alaska 800- 478-3576, so a NOTAM can be issued. For structures that are regulated by the FCC, the FCC advises that noncompliance with notification procedures could subject the Sponsor to penalties or monetary forfeitures. Voluntarily installed lights (not recommended in an FAA determination) do not require a NOTAM.

2.4.2 The following information should be specified for outage reporting:

1. Name of persons or organizations reporting the light failures, including any title, address, and telephone number.

2. The type of structure.

3. Location of structure (including latitude and longitude, prominent structures, landmarks, etc.).

4. Height of structure AGL/above mean sea level (AMSL) if known.

5. Return to service date.

6. FCC Antenna Structure Registration Number (for structures that are regulated by the FCC).

Note: When the primary lamp in a double obstruction light fails and the secondary lamp comes on, no report is required.

2.5 Notification of Restoration

As soon as normal operation is restored, notify Outage Reporting and NOTAM Offices (see Paragraph 2.4.1).

Note: For structures regulated by the FCC, the FCC advises that noncompliance with notification procedures could subject the Sponsor to penalties or monetary forfeitures.

2.6 Federal Communications Commission (FCC) Requirement

The use of a high intensity flashing white lighting system on structures located in residential neighborhoods (as defined by applicable zoning laws) trigger requirements for FCC licenses and an environmental assessment.

2.7 Voluntary Marking of Meteorological Towers Less Than 200 Feet (60.96 m) AGL The FAA recommends marking of meteorological towers less than 200 feet (60.96 m) AGL in accordance with marking guidance contained in this AC. Historically, this guidance has not been applied; however the FAA recognizes the need to address safety impacts to low-level agricultural flight operations and believes that marking meteorological towers less than 200 feet (60.96 m) AGL in remote and rural areas enhances the conspicuity of these structures.

2.7.1 Marking.

The meteorological tower should be marked in accordance with the standards and criteria contained in Chapters 3 and 15, with alternating bands of aviation orange and white. In addition, all markings should be replaced when faded or otherwise deteriorated below approved SAE AMSSTD595A standards (see Chapter 15).

2.7.2 High-visibility sleeves.

It is recommended that several high-visibility sleeves be installed on the meteorological tower outer guy wires (see Figure A-2). One high-visibility sleeve should be installed on each guy wire, as close to the anchor point as possible, but at a height well above the crop or vegetation canopy. A second sleeve should be installed on the same outer guy wires midway between the location of the lower sleeve and the upper attachment point of the guy wire to the meteorological tower.

2.7.3 Spherical markers.

It is also recommended that high-visibility aviation orange spherical marker (or cable) balls are attached to the guy wires. Spherical markers should be installed and displayed in accordance with Chapters 3 and 11. The FAA, however, recognizes various weather conditions and manufacturing placement standards may affect the placement and use of high-visibility sleeves and/or spherical markers. Thus, some flexibility is allowed when determining sleeve length and marker placement on the meteorological tower.

CHAPTER 3. MARKING GUIDELINES

3.1 Purpose

This chapter provides recommended guidelines to make certain structures conspicuous to pilots during daylight hours. One way to achieve this conspicuity is to paint and/or mark these structures. Recommendations on marking structures can vary, depending on terrain features, weather patterns, geographic location, and the number of structures.

3.2 Marking Colors

Alternate sections of aviation orange and white marking should be used as the contrast in colors provides maximum visibility of an obstruction. Specific marking standards are contained in Chapter 15.

3.3 Marking Standards

To be effective, the marking used should meet specific color requirements when freshly applied to a structure. Because all outdoor markings deteriorate with time, and it is not practical to give a maintenance schedule for all climates, surfaces should have markings reapplied when the color changes noticeably or its effectiveness is reduced by scaling, oxidation, chipping, or layers of contamination. The subsequent standards should be followed.

3.3.1 Materials and Application

The FAA recommends that quality markings (paint, powder coat, vinyl wrap, etc.) and materials be selected to maximize years of service. The marking should be appropriate for the surfaces to be marked, including any previous applications, and suitable for the environmental conditions. Surface preparation and marking application should follow the manufacturer’s recommendations.

Note: In-Service Aviation Orange Color Tolerance Charts are available from private suppliers for determining when repainting is appropriate. The color should be sampled on the upper half of the structure where paint weathering is greater.

3.3.2 Surfaces not Requiring Marking

Ladders, decks, and walkways of steel towers and similar structures do not need to be marked if a smooth surface presents a potential hazard to maintenance personnel.

Marking may also be omitted from precision or critical surfaces if the marking would have an adverse effect on the transmission or radiation characteristics of a signal.

However, the structure’s overall marking effect should not be reduced.

3.3.3 Skeletal Structures

Complete all marking/painting prior to or immediately upon completion of construction.

This applies to catenary support structures, radio and television towers, and similar skeletal structures. To be effective, marking should be applied to all inner and outer surfaces of the framework.

3.4 Marking Patterns

Various types of marking patterns are used to distinguish structures. The pattern is determined by the size and shape of the structure. The following patterns are recommended:

3.4.1 Solid Pattern

Obstacles should be marked aviation orange if the structure’s horizontal and vertical dimensions do not exceed 10.5 feet (3.20 m).

3.4.2 Checkerboard Pattern

Alternating rectangles of aviation orange and white are normally displayed on the following structures:

1. Water, gas, and grain storage tanks (see Figures A-3, A-4, and A-5).

2. Buildings, as required.

3. Large structures exceeding 10.5 feet (3.20 m) across, having a horizontal dimension that is equal to or greater than the vertical dimension.

3.4.3 Size of Patterns

The sides of the checkerboard pattern should measure not less than five feet (1.52 m) or more than 20 feet (6.10 m) and should be as nearly square as possible. However, if it is impractical because of the size or shape of a structure, the sides of the patterns may be less than five feet (1.52 m). The pattern should be arranged so that each outer corner of the structure will be painted aviation orange.

3.4.4 Alternate Bands

Alternate bands of aviation orange and white are normally displayed on the following structures:

1. Communication towers and catenary support structures.

2. Poles.

3. Smokestacks.

4. Skeletal framework of storage tanks and similar structures.

5. Structures that appear narrow from a side view that are 10.5 feet (3.20 m) or less across, and the horizontal dimension is less than the vertical dimension.

6. Coaxial cable, conduits, and other cables attached to the face of a tower.

7. Wind turbines in snow prone areas may also use off-white (see Chapter 13) for greater conspicuity.

3.4.5 Color Band Characteristics

Bands for structures of any height (see Figure A-6) should be:

1. Equal in width, provided each band is not less than 1 1/2 feet (0.46 m) or more than

100 feet (30.48 m) wide.

2. Perpendicular to the vertical axis with the bands at the top and bottom marked orange.

3. An odd number of bands on the structure.

4. Equal and in proportion to the structure’s AGL height.

5. Approximately one-seventh the height, if the structure is equal to or less than 700 feet (213.36 m) AGL. For each additional 200 feet (60.96 m) or fraction thereof, add one additional orange and one additional white band. Table 3-1 shows the required band widths based on the height of the structure.

Table 3-1: Structure Height to Bandwidth Ratio

If a structure is: Then Band Width:

Greater Than Equal to or Less Than Band Width

10.5 feet (3.20 m) 700 feet (213.36 m) 1/7 of

700 feet (213.36 m) 900 feet (274.32 m) 1/9 of

900 feet (274.32 m) 1,100 feet (335.28 m) 1/11 of

1,100 feet (335.28 m) 1,300 feet (396.24 m) 1/13 of

3.4.6 Structures With a Cover or Roof

If the structure has a cover or roof, the highest orange band should be continued to cover the entire top of the structure (see Figures A-3 and A-4).

3.4.7 Skeletal Structures Atop Buildings

If a flagpole, skeletal structure, or similar object is erected on top of a building, the combined height of the object and building will determine whether marking is recommended. However, only the height of the object filed with the FAA determines the width of the color bands.

3.4.8 Partial Marking

If marking is recommended for only a portion of a structure because the lower portion of the structure is shielded by other objects or terrain, the width of the bands on the exposed portion should still be determined by the overall height of the structure.

Paragraph 3.4.5.5 provides details on calculating the width of the paint bands. A minimum of three bands should be displayed on the exposed portion of the structure. If the exposed portion of the structure is not large enough to have at least three bands, the width of the bands may be reduced equally so that three equally sized bands can be fit.

This will ensure that the marking pattern provides sufficient contrast for a pilot to locate the structure.

3.4.9 Teardrop Pattern

Spherical water storage tanks with a single, circular standpipe support may be marked in a teardrop-striped pattern. The tank should show alternate stripes of aviation 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 stripe at the greatest girth of the tank should not be less than five feet (1.52 m) nor more than 15 feet (4.57 m) (see Figure A-5).

3.4.10 Community Names

If it is desirable to display the name of the community on the side of a tank or other structure, the stripe pattern may be broken to serve this purpose. This open area should have a maximum height of three feet (0.91 m) (see Figure A-5).

3.4.11 Exceptions

Structural designs not conducive to standard markings may be marked as follows:

1. If it is not practical to mark the roof of a structure in a checkerboard pattern, it may be marked solid orange.

2. If a spherical structure is not suitable for an exact checkerboard pattern, the shape of the rectangles may be modified to fit the shape of the surface.

3. Storage tanks not suitable for a checkerboard pattern may have alternating bands of aviation orange and white or a limited checkerboard pattern applied to the upper one-third of the structure.

4. The skeletal framework of certain water, gas, and grain storage tanks may be excluded from the checkerboard pattern.

5. Solid spherical water tank stands do not require marking.

3.5 Unlighted Markers

Unlighted markers are used to identify structures and to make them more conspicuous when it is impractical to mark them. Unlighted markers may also be used with aviation orange and white markings when additional conspicuity is necessary for aviation safety.

Unlighted markers should be displayed in conspicuous positions on or adjacent to the structures to retain the general definition of the structure. They should be recognizable in clear, daytime visibility from a distance of at least 4,000 feet (1,219.20 m) and in all directions from which aircraft are likely to approach. Unlighted markers should be distinctively shaped, i.e., spherical or cylindrical, so that they are not mistaken for items that are used to convey other information. They should be replaced when faded or otherwise deteriorated.

https://1,219.20

3.5.1 Spherical Markers

Spherical markers are primarily used to identify overhead wires and catenary transmission lines that are less than 69 kilovolts (kV). Markers may be of another shape, i.e., cylindrical, provided the projected area of such markers is not less than that presented by a spherical marker.

3.5.2 Size and Color

The diameter of the markers used on extensive catenary wires (catenary wires that cross canyons, lakes, rivers, etc.) should not be less than 36 inches (91.44 centimeters (cm)).

Smaller 20-inch (50.80-cm) spheres are permitted on less extensive catenary wires or on power lines below 50 feet (15.24 m) AGL and within 1,500 feet (457.20 m) of an airport runway end. Each marker should be a solid color, specifically aviation orange, white, or yellow.

3.5.3 Installation

3.5.3.1 Spacing. Unlighted markers should be spaced equally along the wire at approximately 200-foot (60.96 m) intervals, or fraction thereof. There should be less space between markers in critical areas near runway ends (i.e., 30 feet to 50 feet (9.14 m to 15.24 m)). They should be displayed on the highest wire or by another means at the same height as the highest wire. Where there is more than one wire at the highest point, the markers may be installed alternately along each wire if the distance between adjacent markers meets the spacing standard of 200 feet (60.96 m) or less.

This method distributes the weight and wind-loading factors (see Figures A-21 and A-24).

3.5.3.2 Pattern. An alternating color scheme provides the most conspicuity against all backgrounds. Unlighted markers should be installed by alternating solid-colored markers of aviation orange, white, and yellow. Normally, an orange marker is placed at each end of a line and the spacing is adjusted (not to exceed 200 feet (60.96 m)) to accommodate the rest of the markers.

When less than four markers are used, they should all be aviation orange.

3.5.3.3 Wire Sag. Wire Sag, or droop, will occur due to temperature, wire weight, wind, etc. Twenty-five feet (7.62 m) is the maximum allowable distance between the highest wire installed with marker balls and the highest wire without marker balls and should not violate the sag standards of the transmission line design.

3.5.3.4 Adjacent Lines. Catenary crossings with multiple transmission lines require appropriate markers when the adjacent catenary structure’s outside lines are greater than 200 feet (60.96 m) away from the center of the primary structure. If the outside lines of the adjacent catenary structure are within 200 feet (60.96 m) or less from the center of the primary structure, markers are not required on the adjacent lines.

3.6 Flag Markers

Flags are used to mark certain structures or objects when it is technically impractical to use spherical markers or quality markings (paint, powder coat, vinyl wrap, etc.). Flag markers should be mounted at the highest point of the structure to ensure visibility.

Some common examples of structures that may utilize this type of markers include, temporary construction equipment and vehicles, oil and drilling rigs, cranes, and derricks.

3.6.1 Minimum Size

Each side of the flag marker should be at least two feet (0.61 m) in length.

3.6.2 Color Patterns

Flags should be colored as follows:

1. Solid. Aviation orange.

2. Orange and White. Arrange two triangular sections, one aviation orange, and the other white to form a rectangle.

3. Checkerboard. Flags three feet (0.91 m) or larger should be a checkerboard pattern of aviation orange and white squares, each one foot (0.30 m) plus or minus 10 percent.

4. Shape. Flags should be rectangular in shape and have stiffeners to keep them from drooping in calm wind.

3.6.3 Display. Flag markers should be displayed around, on top, or along the highest edge of the obstruction. When flags are used to mark extensive or closely grouped obstructions, they should be displayed approximately 50 feet (15.24 m) apart. The flag stakes should be strong enough to support the flags and be higher than the surrounding ground, structures, and/or objects of natural growth.

3.7 Omission or Alternatives to Marking

The alternatives listed below require FAA review and concurrence prior to making changes. See subsequent chapters for specific guidance.

3.7.1 High Intensity Flashing White Lighting Systems are more effective than aviation orange and white marking and therefore can be recommended instead of paint marking. This is particularly true under certain ambient light conditions involving the position of the sun relative to the direction of flight. High-intensity lighting systems should not be used on structures 700 feet (213.36 m) AGL or less, however, when operated during daytime, twilight, or 24 hours a day, other methods of marking and lighting may be omitted.

3.7.2 Medium Intensity Flashing White Lighting Systems are operated during daytime and twilight on structures 700 feet (213.36 m) AGL or less, but generally not on structures less than 200 feet (60.96 m) AGL. When used, other methods of marking may be omitted.

Note: Note: Sponsors may need to coordinate alternative markings with the FCC for certain structures prior to making any changes.

3.8 Unusual Complexities

The FAA may also recommend appropriate marking in an area in which grouped obstructions present a common obstruction to air navigation.

CHAPTER 4. LIGHTING GUIDELINES

4.1 Purpose

This chapter describes the various obstruction lighting systems used to identify structures that have been determined to require added conspicuity. The lighting standards in this Advisory Circular (AC) are the minimum necessary for aviation safety.

Recommendations for lighting structures can vary, depending on terrain features, weather patterns, geographic location, and number of structures.

4.2 Standards

The standards outlined in this A/C are based on using light units that meet specified intensities, beam patterns, color, and flash rates as stated in AC 150/5345-43, Specification for Obstruction Lighting Equipment. The AC may be obtained from:

https://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.inf ormation/documentID/1035508.

4.3 Lighting Systems

All flashing lights on a structure should flash simultaneously except for catenary support structures, which have a distinct flashing sequence between the levels of lights (see paragraph 11.4.2). Obstruction lighting may be displayed on structures as follows (refer to subsequent chapters for details):

1. Aviation Red Obstruction Lights.

Use flashing lights and/or steady-burning lights during nighttime. Tower structures are typically marked with flashing red lights. Buildings and smaller obstructions located near airports should be marked with steady-burning red lights.

2. Medium Intensity Flashing White Obstruction Lights.

Medium intensity flashing white obstruction lights may be used during daytime and twilight with automatic reduced intensity selected for nighttime operation. When this system is used on structures 700 feet (213.36 m) AGL or less, other methods of marking and lighting the structure may be omitted. Aviation orange and white marking is always required for daytime marking on structures exceeding 700 feet (213.36 m) AGL. This system is not normally recommended on structures 200 feet (60.96 m) AGL or less.

3. High Intensity Flashing White Obstruction Lights.

High intensity flashing white obstruction lights may be used during daytime, with automatically selected reduced intensities for twilight and nighttime operations.

When this system is used, other methods of marking and lighting the structure may be omitted. This system should not be used on structures 700 feet (213.36 m) AGL or less unless an FAA aeronautical study shows otherwise.

https://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/1035508 https://www.faa.gov/regulations_policies/advisory_circulars/index.cfm/go/document.information/documentID/1035508

4. Dual Lighting.

This system consists of red lights for nighttime and high- or medium-intensity flashing white obstruction lights for daytime and twilight. When a dual lighting system incorporates medium-intensity flashing white lights on structures 700 feet (213.36 m) AGL or less or high-intensity flashing white lights on structures greater than 700 feet (213.36 m) AGL, other methods of marking the structure may be omitted.

5. Lighted Spherical Markers.

Lighted markers are available for increased night conspicuity of high-voltage (69 kV or greater) transmission line catenary wires and should be manufacturer-certified as, visible and recognizable from a minimum distance of 4,000 feet (1,219.20 m) under nighttime conditions and under minimum VFR…