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CHAPTER 8. DUAL LIGHTING WITH RED/MEDIUM INTENSITY FLASHING WHITE SYSTEMS
80. PURPOSE This dual lighting system includes red lights (L-864) for nighttime and medium intensity flashing white lights (L-865) for daytime and twilight use. This lighting system may be used in lieu of operating a medium intensity flashing white lighting system at night. There may be some populated areas where the use of medium intensity at night may cause significant environmental concerns. The use of the dual lighting system should reduce/mitigate those concerns.
Recommendations on lighting structures can vary depending on terrain features, weather patterns, geographic location, and in the case of wind turbines, number of structutes and overall layout of design.
81. INSTALLATION The light units should be installed as specified in the appropriate portions of Chap ters 4, 5, and 6. The number of light levels needed may be obtained from Appendix 1.
82. OPERATION Lighting systems should be operated as specified in Chapter 3. Both systems should not be operated at the same time; however, there should be no more than a 2- second delay when changing from one system to the other. Outage of one of two lamps in the uppermost red beacon (L-864 incandescent unit) or outage of any uppermost red light shall cause the white obstruction light system to operate in its specified ”night” step intensity.
83. CONTROL DEVICE The light system is controlled by a device that changes the system when the ambient light changes. The system should automatically change steps when the northern sky illumination in the Northern Hemisphere on a vertical surface is as follows:
a. Twilight-to-Night. This should not occur before the illumination drops below 5 foot-candles (53.8 lux) but should occur before it drops below 2 foot-candles
(21.5 lux).
b. Night-to-Day. The intensity changes listed in subparagraph 83 a above should be reversed when changing from the night to day mode.
84. ANTENNA OR SIMILAR APPURTENANCE LIGHT When a structure utilizing this dual lighting system is topped with an antenna or similar appurtenance exceeding 40 feet (12m) in height, a medium intensity flashing white (L-865) and a red flashing beacon (L-
864) should be placed within 40 feet (12m) from the tip of the appurtenance. The white light should operate during daytime and twilight and the red light during nighttime. These lights should flash simultaneously with the rest of the lighting system.
85. OMISSION OF MARKING When medium intensity white lights are operated on structures 500 feet (153m) AGL or less during daytime and twilight, other methods of marking may be omitted.
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CHAPTER 9. DUAL LIGHTING WITH RED/HIGH INTENSITY FLASHING WHITE SYSTEMS
90. PURPOSE This dual lighting system includes red lights (L-864) for nighttime and high intensity flashing white lights (L-856) for daytime and twilight use. This lighting system may be used in lieu of operating a flashing white lighting system at night. There may be some populated areas where the use of high intensity lights at night may cause significant environmental concerns and complaints. The use of the dual lighting system should reduce/mitigate those concerns.
Recommendations on lighting structures can vary depending on terrain features, weather patterns, geographic location, and in the case of wind turbines, number of structutes and overall layout of design.
91. INSTALLATION The light units should be installed as specified in the appropriate portions of Chap ters 4, 5, and 7. The number of light levels needed may be obtained from Appendix 1.
92. OPERATION Lighting systems should be operated as specified in Chapters 4, 5, and 7. Both systems should not be operated at the same time; however, there should be no more than a 2-second delay when changing from one system to the other. Outage of one of two lamps in the uppermost red beacon (L-864 incandescent unit) or outage of any uppermost red light shall cause the white obstruction light system to operate in its specified “night” step intensity.
93. CONTROL DEVICE The light intensity is controlled by a device that changes the intensity when the ambient light changes.
The system should automatically change intensity steps when the northern sky illumination in the Northern Hemisphere on a vertical surface is as follows:
a. Day-to-Twilight. This should not occur before the illumination drops to 60 foot-candles (645.8 lux) but should occur before it drops below 35 foot-candles
(376.7 lux). The illuminance-sensing device should, if practical, face the northern sky in the Northern Hemisphere.
b. Twilight-to-Night. This should not occur before the illumination drops below 5 foot-candles (53.8 lux) but should occur before it drops below 2 foot-candles
(21.5 lux).
c. Night-to-Day. The intensity changes listed in subparagraph 93 a and b a bove should be reversed when changing from the night to day mode.
94. ANTENNA OR SIMILAR APPURTENANCE LIGHT When a structure utilizing this dual lighting system is topped with an antenna or similar appurtenance exceeding 40 feet (12m) in height, a medium intensity flashing white light (L-865) and a red flashing beacon (L-864) should be placed within 40 feet (12m) from the tip of the appurtenance. The white light should operate during daytime and twilight and the red light during nighttime.
95. OMISSION OF MARKING When high intensity white lights are operated during daytime and twilight, other methods of marking may be omitted.
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CHAPTER 10. MARKING AND LIGHTING OF CATENARY AND CATENARY SUPPORT STRUCTURES
100. PURPOSE This chapter provides guidelines for marking and lighting catenary and catenary support structures. The recommended marking and lighting of these structures is intended to provide day and night conspicuity and to assist pilots in identifying and avoiding catenary wires and associated support structures.
101. CATENARY MARKING STANDARDS Lighted markers are available for increased night conspicuity of high-voltage (69KV or greater) transmission line catenary wires. These markers should be used on transmission line catenary wires near airports, heliports, across rivers, canyons, lakes, etc. The lighted markers should be manufacturer certified as recognizable from a minimum distance of 4,000 feet (1219m) under nighttime conditions, minimum VFR conditions or having a minimum intensity of at least 32.5 candela. The lighting unit should emit a steady burning red light. They should be used on the highest energized line. If the lighted markers are installed on a line other than the highest catenary, then markers specified in paragraph 34 should be used in addition to the lighted markers. (The maximum distance between the line energizing the lighted markers and the highest catenary above the lighted marker should be no more than 20 feet (6m).)
Markers should be distinctively shaped, i.e., spherical, cylindrical, so they are not mistaken for items that are used to convey other information. They should be visible in all directions from which aircraft are likely to approach. The area in the immediate vicinity of the supporting structure’s base should be clear of all items and/or objects of natural growth that could interfere with the line-of-sight between a pilot and the structure’s lights. Where a catenary wire crossing requires three or more supporting structures, the inner structures should be equipped with enough light units per level to provide a full coverage.
a. Size and Color. The diameter of the markers used on extensive catenary wires across canyons, lakes, rivers, etc., should be not less than 36 inches (91cm).
Smaller 20-inch (51cm) markers are permitted on less extensive power lines or on power lines below 50 feet (15m) above the ground and within 1,500 feet (458m) of an airport runway end. Each marker should be a solid color such as aviation orange, white, or yellow.
b. Installation.
1. Spacing. Lighted markers should be spaced equally along the wire at intervals of approximately 200 feet (61m) or a fraction thereof. Intervals between markers should be less in critical areas near runway ends, i.e., 30 to 50 feet (10m to 15m). If the markers are installed on a line other than the highest catenary, then markers specified in paragraph 34 should be used in addition to the lighted markers. The maximum distance between the line energizing the lighted markers and the highest catenary above the markers can be no more than 20 feet (6m). The lighted markers may be installed alternately along each wire if the distance between adjacent markers meets the spacing standard. This method allows the weight and wind loading factors to be distributed.
2. Pattern. An alternating color scheme provides the most conspicuity against all backgrounds. Mark overhead wires 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 (61m)) to accommodate the rest of the markers. When less than four markers are used, they should all be aviation orange.
102. CATENARY LIGHTING STANDARDS When using medium intensity flashing white (L-866), high intensity flashing white (L-857), dual medium intensity (L-866/L-885) or dual high intensity (L- 857/885) lighting systems, operated 24 hours a day, other marking of the support structure is not necessary.
a. Levels. A system of three levels of sequentially flashing light units should be installed on each supporting structure or adjacent terrain. Install one level at the top of the structure, one at the height of the lowest point in the catenary and one level approximately midway between the other two light levels. The middle level should normally be at least 50 feet (15m) from the other two levels. The middle light unit may be deleted when the distance between the top and the bottom light levels is less than 100 feet (30m).
1. Top Levels . One or more lights should be installed at the top of the structure to provide 360- degree coverage ensuring an unobstructed view. If the installation presents a potential danger to maintenance personnel, or when necessary for lightning protection, the top level of lights may be mounted as low as 20 feet (6m) below the highest point of the structure.
2. Horizontal Coverage . The light units at the middle level and bottom level should be installed so as to provide a minimum of 180-degree coverage centered perpendicular to the flyway. Where a catenary crossing is situated near a bend in a river, canyon, etc., or is not perpendicular to the flyway, the Chap 10 27
2/1/07AC 70/7460-1K CHG 2 horizontal beam should be directed to provide the most effective light coverage to warn pilots approaching from either direction of the catenary wires.
3. Variation. The vertical and horizontal arrangements of the lights may be subject to the structural limits of the towers and/or adjacent terrain.
A tolerance of 20 percent from uniform spacing of the bottom and middle light is allowed. If the base of the supporting structure(s) is higher than the lowest point in the catenary, such as a canyon crossing, one or more lights should be installed on the adjacent terrain at the level of the lowest point in the span. These lights should be installed on the structure or terrain at the height of the lowest point in the catenary.
b. Flash Sequence . The flash sequence should be middle, top, and bottom with all lights on the same level flashing simultaneously. The time delay between flashes of levels is designed to present a unique system display. The time delay between the start of each level of flash duration is outlined in FAA AC 150/5345-43, Specification for Obstruction Lighting Equipment.
c. Synchronization. Although desirable, the corresponding light levels on associated supporting towers of a catenary crossing need not flash simultaneously.
d. Structures 500 feet (153m) AGL or Less. When medium intensity white lights (L-866) are operated 24 hours a day, or when a dual red/medium intensity system (L-866 daytime & twilight/L-885 nighttime) is used, marking can be omitted. When using a medium intensity while light (L-866) or a flashing red light (L-
885) during twilight or nighttime only, painting should be used for daytime marking.
e. Structures Exceeding 500 Feet (153m) AGL.
When high intensity white lights (L-857) are operated 24 hours a day, or when a dual red/high intensity system (L-857 daytime and twilight/L-885 nighttime) is used, marking can be omitted. This system should not be recommended on structures 500 feet (153m) or less unless an FAA aeronautical study shows otherwise. When a flashing red obstruction light (L-
885), a medium intensity (L-866) flashing white lighting system or a high intensity white lighting system (L-857) is used for nighttime and twilight only, painting should be used for daytime marking.
103. CONTROL DEVICE The light intensity is controlled by a device (photocell) that changes the intensity when the ambient light changes. The lighting system should automatically change intensity steps when the northern sky illumination in the Northern Hemisphere on a vertical surface is as follows:
a. Day-to-Twilight (L-857 System). This should not occur before the illumination drops to 60 foot-candles
(645.8 lux), but should occur before it drops below 35 foot-candles (376.7 lux). The illuminant-sensing device should, if practical, face the northern sky in the Northern Hemisphere.
b. Twilight-to-Night (L-857 System). This should not occur before the illumination drops below 5 footcandles (53.8 lux), but should occur before it drops below 2 foot-candles (21.5 lux).
c. Night-to-Day. The intensity changes listed in subparagraph 103 a. and b. above should be reversed when changing from the night to day mode.
d. Day-to-Night (L-866 or L-885/L-866). This should not occur before the illumination drops below 5 foot-candles (563.8 lux) but should occur before it drops below 2 foot-candles (21.5 lux).
e. Night-to-Day. The intensity changes listed in subparagraph d. above s hould be reversed when changing from the night to day mode.
f. Red Obstruction (L-885) . The red lights should not turn on until the illumination drops below 60 footcandles (645.8 lux) but should occur before reaching a level of 35 foot-candles (367.7 lux). Lights should not turn off before the illuminance rises above 35 footcandles (367.7 lux), but should occur before reaching 60 foot-candles (645.8 lux).
104. AREA SURROUNDING CATENARY SUPPORT
STRUCTURES The area in the immediate vicinity of the supporting structure’s base should be clear of all items and/or objects of natural growth that could interfere with the line-of-sight between a pilot and the structure’s lights.
105. THREE OR MORE CATENARY SUPPORT
STRUCTURES Where a catenary wire crossing requires three or more supporting structures, the inner structures should be equipped with enough light units per level to provide a full 360-degree coverage.
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CHAPTER 11. MARKING AND LIGHTING MOORED BALLOONS AND KITES
110. PURPOSE The purpose of marking and lighting moored balloons, kites, and their cables or mooring lines is to indicate the presence and general definition of these objects to pilots when converging from any normal angle of approach.
111. STANDARDS These marking and lighting st andards pertain to all moored balloons and kites that require marking and lighting under 14 CFR, part 101.
112. MARKING Flag markers should be used on mooring lines to warn pilots of their presence during daylight hours.
a. Display. Markers should be displayed at no more than 50-foot (15m) intervals and should be visible for at least 1 statute mile.
b. Shape. Markers should be rectangular in shape and not less than 2 feet (0.6m) on a side. Stiffeners should be used in the borders so as to expose a large area, prevent drooping in calm wind, or wrapping around the cable.
c. Color Patterns. One of the following color patterns should be used:
1. Solid Color. Aviation orange.
2. Orange and White. Two triangular sections, one of aviation orange and the other white, combined to form a rectangle.
113. PURPOSE Flashing obstruction lights should be used on moored balloons or kites and their mooring lines to warn pilots of their presence during the hours between sunset and sunrise and during periods of reduced visibility. These lights may be operated 24 hours a day.
a. Systems. Flashing red (L-864) or white beacons (L-865) may be used to light moored balloons or kites.
High intensity lights (L-856) are not recommended.
b. Display . Flashing lights should be displayed on the top, nose section, tail section, and on the tether cable approximately 15 feet (4.6m) below the craft so as to define the extremes of size and shape. Additional lights should be equally spaced along the cable’s overall length for each 350 feet (107m) or fraction thereof.
c. Exceptions. When the requirements of this paragraph cannot be met, floodlighting may be used.
114. OPERATIONAL CHARACTERISTICS The light intensity is controlled by a device that changes the intensity when the ambient light changes.
The system should automatically turn the lights on and change intensities as ambient light condition change.
The reverse order should apply in changing from nighttime to daytime operation. The lights should flash simultaneously.
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CHAPTER 12. MARKING AND LIGHTING EQUIPMENT AND INFORMATION
120. PURPOSE This chapter lists documents relating to obstruction marking and lighting systems and where they may be obtained.
121. PAINT STANDARD Paint and aviation colors/gloss, referred to in this publication should conform to Federal Standard FED-STD-595. Approved colo rs shall be formulated without the use of Lead, Zinc Chromate or other heavy metals to match International Orange, White and Yellow. All coatings shall be manufactured and labeled to meet Federal Environmental Protection Act Volatile Organic Compound(s) guidelines, including the National Volatile Organic Compound Emission Standards for architectural coatings.
a. Exterior Acrylic Waterborne Paint. Coating should be a ready mixed, 100% acrylic, exterior latex formulated for application directly to galvanized surfaces. Ferrous iron and steel or non-galvanized surfaces shall be primed with a manufacturer recommended primer compatible with the finish coat.
b. Exterior Solventborne Alkyd Based Paint .
Coating should be ready mi xed, alkyd-based, exterior enamel for application directly to non-galvanized surfaces such as ferrous iron and steel. Galvanized surfaces shall be primed with a manufacturer primer compatible with the finish coat.
Paint Standards Color Table
COLOR NUMBER Orange 12197 White 17875 Yellow 13538 TBL 3
Note-
1. Federal specification T1-P-59, aviation surface paint, ready mixed international orange.
2. Federal specification T1-102, aviation surface paint, oil titanium zinc.
3. Federal specification T1-102, aviation surface paint, oil, exterior, ready mixed, white and light tints.
122. AVAILABILITY OF SPECIFICATIONS Federal specifications describing the technical characteristics of various paints and their application techniques may be obtained from:
GSA- Specification Branch 470 L’Enfant Plaza Suite 8214 Washington, DC 20407 Telephone: (202) 619-8925
123. LIGHTS AND ASSOCIATED EQUIPMENT The lighting equipment referred to in this publication should conform to the latest edition of one of the following specifications, as applicable:
a. Obstruction Lighting Equipment.
1. AC 150/5345-43, FAA Specification for Obstruction Lighting Equipment.
2. Military Specifications MIL-L-6273, Light, Navigational, Beacon, Obstacle or Code, Type G-1.
3. Military Specifications MIL-L-7830, Light Assembly, Markers, Aircraft Obstruction.
b. Certified Equipment.
1. AC 150/5345-53, Airport Lighting Certification Program, lists the manufacturers that have demonstrated compliance with the specification requirements of AC 150/5345-43.
2. Other manufacturers’ equipment may be used provided that equipment meets the specification requirements of AC 150/5345-43.
c. Airport Lighting Installation and Maintenance.
1. AC 150/5340-21, Airport Miscellaneous Lighting Visual Aids, provides guidance for the installation, maintenance, testing, and inspection of obstruction lighting for airport visual aids such as airport beacons, wind cones, etc.
2. AC 150/5340-26, Maintenance of Airport Visual Aid Facilities, provides guidance on the maintenance of airport visual aid facilities.
d. Vehicles.
1. AC 150/5210-5, Painting, Marking, and Lighting of Vehicles Used on an Airport, contains provisions for marking vehicles principally used on airports.
2. FAA Facilities. Obstruction marking for FAA facilities shall conform to FAA Drawing Number D- 5480, referenced in FAA Standard FAA-STD-003, Paint Systems for Structures.
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AC 70/7460-1K CHG 2 2/1/07
124. AVAILABILITY The standards and specifications listed above may be obtained free of charge from the below-indicated office:
a. Military Specifications:
Standardization Document Order Desk 700 Robbins Avenue Building #4, Section D Philadelphia, PA 19111-5094
b. FAA Specifications:
Manager, ASD-110 Department of Transportation Document Control Center Martin Marietta/Air Traffic Systems 475 School St., SW.
Washington, DC 20024 Telephone: (202) 646-2047 FAA Contractors Only
c. FAA Advisory Circulars:
Department of Transportation TASC Subsequent Distribution Office, SVC-121.23 Ardmore East Business Center 3341 Q 75th Avenue Landover, MD 20785 Telephone: (301) 322-4961
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CHAPTER 13. MARKING AND LIGHTING WIND TURBINE FARMS
130. PURPOSE This chapter provides guidelines for the marking and lighting of wind turbine farms. For the purposes of this advisory circular, wind turbine farms are defined as a wind turbine development that contains more than three (3) turbines of heights over 200 feet above ground level. The recommended marking and lighting of these structures is intended to provide day and night conspicuity and to assist pilots in identifying and avoiding these obstacles.
131. GENERAL STANDARDS The development of wind turbine farms is a very dynamic process, which constantly changes based on the differing terrain they are built on. Each wind turbine farm is unique; therefore it is important to work closely with the spon sor to determine a lighting scheme that provides for the safety of air traffic. The following are guidelines that are recommended for wind turbine farms. Consider the proximity to airports and VFR routes, extreme terrain where heights may widely vary, and local flight activity when making the recommendation.
a. Not all wind turbine units within an installation or farm need to be lighted. Definition of the periphery of the installation is essential; however, lighting of interior wind turbines is of lesser importance unless they are taller than the peripheral units.
b. Obstruction lights within a group of wind turbines should have unlighted separations or gaps of no more than ½ statute mile if the integrity of the group appearance is to be maintained. This is especially critical if the arrangement of objects is essentially linear.
c. Any array of flashing or pulsed obstruction lighting should be synchronized or flash simultaneously.
d. Nighttime wind turbine obstruction lighting should consist of the preferred FAA L-864 aviation red-colored flashing lights.
e. White strobe fixtures (FAA L-865) may be used in lieu of the preferred L-864 red flashing lights, but must be used alone without any red lights, and must be positioned in the same manner as the red flashing lights.
f. The white paint most often found on wind turbine units is the most effective daytime early warning device. Other colors, such as light gray or blue, appear to be significantly less effective in providing daytime warning. Daytime lighting of wind turbine farms is not required, as long as the turbine structures are painted in a bright white color or light off-white color most often found on wind turbines.
132. WIND TURBINE CONFIGURATIONS – Prior to recommending marking and lighting, determine the configuration and the terrain of the wind turbine farm. The following is a description of the most common configurations.
a. Linear – wind turbine farms in a line-like arrangement, often located along a ridge line, the face of a mountain or along borders of a mesa or field.
The line may be ragged in shape or be periodically broke, and may vary in size from just a few turbines up to 20 miles long.
b. Cluster – turbine fa rms where the turbines are placed in circles like groups on top of a mesa, or within a large field. A cluster is typically characterized by having a pronounced perimeter, with various turbines placed inside the circle at various, erratic distances throughout the center of the circle.
c. Grid – turbine farms arranged in a geographical shape such as a square or a rectangle, where each turbine is set a consistent distance from each other in rows, giving the appearance that they are part of a square like pattern.
133. MARKING STANDARDS The bright white or light off-white paint most often found on wind turbines has been shown to be most effective, and if used, no lights are required during the daytime. However, if darker paint is used, wind turbine marking should be supplemented with daytime lighting, as required.
134. LIGHTING STANDARDS
a. Flashing red (L864), or white (L-865) lights may be used to light wind turbines. Studies have shown that red lights are most effective, and should be the first consideration for lighting recommendations of wind turbines.
b. Obstruction lights should have unlighted separations or gaps of no more than ½ mile. Lights should flash simultaneously. Should the synchronization of the lighting system fail, a lighting outage report should be made in accordance with paragraph 23 of this advisory circular. Light fixtures should be placed as high as possible on the turbine nacelle, so as to be visible from 360 degrees.
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