1 Oct 72 AC 70/7460-1B * High Intensity White Obstruction Lighting. The operation of high intensity white obstruction lighting installed on obstructions should be controlled by a satisfactory control device.
The control device used should be adjusted so that the lights will be turned on at their highest daytime intensity when the north sky light illuminance rises to one-half footcandle, but before that illuminance level reacnes three footcandles.
high intensity white obstruction lighting is displayed on an obstruction during nighttime periods, the lighting should be controlled by a satisfactory control device. The control device used should be adjusted so that the lights will be turned on at the lower (night) intensity when the north sky illuminance falls half footcandle. to three footcandles, but before that illuminance reaches one-
(3) Dual Obstruction Lighting Systems. When high intensity white obstruction lighting is displayed on an obstruction during the daylight hours and only aviation red obstruction lighting is displayed on that obstruction during the nighttime hours, the two lighting systems should be controlled by one or more satisfactory control devices. The control devices used should be adjusted so that the high intensity white obstruction lights will be turned on and the red lights turned off when the north sky illuminance rises to one-half footcandle but before that illuminance reaches three footcandles, and will be turned off and the red lights turned on when the north sky illuminance falls to three footcandles but before that illuminance level reaches one-half footcandle.
Light Control Device. The operation of obstruction lighting displayed on obstructions should be controlled by one or more automatic time control, manual switching or light sensitive control devices. If a light-sensitive control device is used, it should be adjusted as in this subsection and installed so that the illuminance sensing device faces the north sky.
c. Inspection of Obstruction Lighting. Obstruction lighting should be visually observed at least once each 24 hours, or checked by observing an automatic and properly maintained indicator designed to register any failure of such lights to insure that all such lights are functioning properly as required.
Chap. 4 Par. 13 Page 15
AC 70/7460-1B I Oct 72 * Automatic Alarm System. is not readily accessible for visual observation at least once In the event the obstruction lighting may be installed and operated to replace the normally required visual inspection. Under such conditions the FAA will not failure of the lights and to provide indication of such failure, each 24 hours, an automatic alarm system, designed to detect any percent of their normal life expectancy. Xenon flash tubes are exempted from this replacement requirement. all top lights; and that all obstruction lighting mounted on the obstruction are visually inspected at least once every two weeks, intervals after being lighted the equivalent of not more than 75 with all the lamps and/or light units being replaced at regular lights, regardless of their position on the obstruction, and of all flashing and rotating beacons and/or high intensity white provided the signalling device will indicate malfunctioning of lights on an obstruction being excluded from the alarm circuit, object to the side or intermediate aviation red obstruction
(2) Lamp Replacement. Except as specified in paragraph 13c(1), a immediate replacement purposes at all times. sufficient supply of spare lamps should be maintained for
d. ment or improper functioning is not necessary. corrected as soon as possible, but notification of such extinguish- or lights, installed on a natural or man-made obstruction should be normal operation by the light, or lights. Any extinguishment or improper functioning of a steady burning side or intermediate light, by telephone or telegraph to the nearest flight service station or lights, the circumstance which caused the failure and the probable date that normal operation will be resumed. Further notification by telephone or telegraph should be given immediately upon resumption of minutes, should be immediately reported. Such reports should be made office of FAA and should set forth the condition of the light, or Notification of Light Failure. Any observed or otherwise known of any natural or man-made obstruction, which will last more than 30 beacon light, regardless of its position on a natural or man-nade steady burning obstruction light, installed at the top or near top obstruction, which will last more than 30 minutes, and any observed or otherwise known extinguishment or improper functioning of a extinguishment or improper functioning of a flashing and rotating rage 16 Спар. 4
I Oct 72 AC 70/7460-1B
e. Flashing Frequency of Aviation Red Obstruction Lights,
(1) Aviation Red Rotating Beacon. An aviation red rotating beacon more than 15 times per minute. should produce a flash not less than 12 times per minute nor Aviation Red Flashing Beacon, An aviation red flashing beacon should be equipped with a flashing mechanism producing not more than 40 flashes per minute nor less than 12 flashes per minute with a period of darkness equal to approximately one-half the luminous period, except that the frequency of flashes of an obstruction beacon mounted on an obstruction located within 15,000 feet of the reference point of a landing area should be not less than 20 per minute. A flashing beacon may flash an International Morse Code Signal for purposes of identification, provided the code characteristic does not consist of more than two letters, the proper aviation color characteristic is retained, and the luminous output of the beacon is not affected in such a manner as to reduce the beacon's effectiveness in performing the service for which it was originally installed.
The duration of the illumination and eclipse periods is important to insure a maximum light intensity. Therefore, an effort should be made to have code assignments adjusted, insofar as possible, to the following timing:
Duration of dot - 0,5 second Duration of dash - 1.5 seconds Duration of eclipse - 0.5 second between dots and dashes of a particular letter Duration of eclipse - 1,5 seconds between letter and repetition of single letter characteristics Duration of eclipse - 2.0 seconds between characteristics which contain two letters Each proposal to have a flashing beacon flash an identifying code should be coordinated with the FAA official designated by the regional director having jurisdiction over the functions of the FAA in the area in which the particular beacon is located.
(b) Approval must be obtained from the Federal Communications Commission for the modification of any obstruction lighting system which comes within the jurisdiction of that agency.
Chap.
Par.
AC 70/7460-1B I Oct 72 taneous flashing of all lights will be permissible. Aviation Red Intermediate Lights. necessary for the intermediate lights to flash, the simul- in obstruction lighting circuits is installed so as to make it If the flashing mechanism should be 40 flashes per minute with deviation from this flash rate not greater than plus or minus five percent. level must flash simultaneously. The flash rate of each light from any direction from the obstruction and all lights on the same high intensity white obstruction lights, except those used to mark obstruction that appear as a vertical line of lights when viewed Flashing Frequency of High Intensity White Obstruction Lights. All transmission lines and their support structures, displayed on an
14. SPECIAL CONDITIONS.
a. Lighting Variables. Obstruction lighting shall be displayed on following combinations: smokestacks, chimneys, and similar obstructions in any of the
(3) (2) Chapter 8, for daytime operation. and flashing high intensity white lights, as specified in steady burning aviation red lights for nighttime operation Lights. A combination of flashing aviation red beacons and Combination Aviation Red and High Intensity White Obstruction during both daytime and nighttime operation. High Intensity White Obstruction Lights. Flashing high intensity white obstruction lights, as specified in Chapter 7, in Chapter 6, during nighttime operation. beacons and steady burning aviation red lights, as specified Aviation Red Obstruction Lights. Flashing aviation red Interference. Where any obstruction lights displayed on an should be given to mitigating or eliminating the adverse effects person or persons in the vicinity of the lights, consideration trains or motor vehicles, or may be a source of irritation to any obstruction may present a problem to the safe operation of railway Page 18 Chap. 4 Par. 13
1 Oct 72 AC 70/7460-1B Where aviation red obstruction lighting is installed on obstructions which are located along or near railroad rightsof-way and thereby constitutes a potential hazard to the safe operation of railway trains, extreme care should be taken to prevent any possibility of these obstruction lights being mistaken by locomotive engineers for railway signal lights.
Shielding of the obstruction lights from the view of the locomotive engineers, if practicable, should be considered; the steady burning lights on the obstruction may be made to flash;
or the lights at the lower levels of the obstruction may be extinguished if their extinguishment does not materially the obstruction. increase the hazard to air navigation caused by the presence of
(2) Other Situations. Where high intensity white lighting is installed on obstructions which are located near highways, waterways or in populated areas, the angle above the horizontal if doing so will not materially increase the hazard to air be found necessary to manually shield or extinguish that light, of the light beam of the lowest light may be increased or it may navigation, to avoid a potential hazard to surface transportation or agitation to residents of private dwellings. If the waterway is navigable, the light installation must be coordinated with the ' marine navigation. Commandant, United States Coast Guard to avoid interference with
(3) Responsibility. The FAA official designated by the regional director is responsible for assuring that such obstruction lighting installations are fully coordinated with all parties concerned and that proper corrective measures are determined and placed in effect.
Day Lighting. The display of flashing or steady burning lights during daylight hours on an obstruction to provide protection in addition to that provided by the applicable marking standards described in Chapter 3, may be prescribed in some instances to more adequately warn airmen of the presence of such an obstruction.
Chap. 4 Par. 14 Page 19
AC 70/7460-1B 1 Oct 72
d. additional obstruction lights should be placed on the highest part airport imaginary surface may not be the highest above a horizontal to the airport imaginary surface. of the object as well as on the point or edge highest in relation (i.e., sloping), this point or edge highest in relation to the plane passing through the base of the object. imaginary surface concerned is an approach or transition surface tion, In certain cases, however, such as when the airport imaginary surface should be regarded as theitop of the obstruc- Building Lighting. When the upper portion of a building or surface, as described in Part 77 of the Federal Aviation Regula- similar extensive object projects above an airport imaginary tions, the point or edge highest in relation to the airport In such cases,
e. Temporary Warning Lights. When an obstruction to air navigation is presented during construction of a structure at least two lights, each light consisting of a lamp of at least 100 watts enclosed in lighting fixtures at each required level, in lieu of the above temporary warning lights, as each such level is exceeded in height practicable, to install and operate the permanent obstruction lights have been installed and placed in operation, and should be approach. It will be permissible, in the event it is more ed nightly from sunset to sunrise until the permanent obstruction of the lights at each level from aircraft at any normal angle of positioned so as to insure unobstructed visibility of at least one lights will be required, two similar lights should be installed at the structure exceeds each level at which permanent obstruction each such level. Thesę temporary warning lights should be display- uppermost point of the structure, In addition, as the height of an aviation red obstruction light globe, should be installed at the
f. Obstruction Lighting by Nonstandard Lights. Obstruction lighting greater light intensity in all angles of azimuth and elevation than characteristics prescribed in Chapter 5. cent lamps, provided such lighting installations offer equal or that specified for standard obstruction light assemblies, afford equal or greater dependability of operation, and possess the color specified under the recommended lamp equipment, gaseous tubes such installations may utilize incandescent lamps other than those as neon tubes, or any method other than the conventional incandes- Page 20 Chap. 4 Par. 14
I Oct 72 AC 70/7460-1B CHAPTER 5. OBSTRUCTION MARKING AND LIGHTING EQUIPMENT
15. PAINT. Paint and aviation colors referred to in the standards set tions: forth in this publication should conform with the following specifica-
(1) Orange No. 12197 (Aviation Surface Orange).
(2) White No. 17875 (Aviation White).
b. Aviation Surface Paint.
(1) Federal Specification TT-P-59 Paint, Ready-Mixed, Internation- al Orange.
(2) Federal Specification TT-P-102 Paint, 01l, Titanium-Lead-Zinc and Oil, Exterior, Ready-Mixed, white and light tints. *
16. LIGHTS AND ASSOCIATED EQUIPMENT. The lighting equipment referred to in the standards set forth in this publication should conform with the applicable provisions of the following specifications and their related drawings.
a. Aviation Red Obstruction Lighting Systens.
(1) Color. Military Specification MIL-C-25050 Colors; Aeronautical Lights and Lighting Equipment.
(2) Rotating Beacons.
(a) FAA Specification 291. Beacons, 36-inch, Rotating Double-Ended Type.
(b) Military Specification MIL-L-7158. Lamp Assembly, 24- inch, Rigid Drum-type Rotating Beacon.
(3) Flashing Code Beacons. FAA Specification 446. Code Beacons, 300 mm.
(4) Double and Single Obstruction Lights.
Military Specification MIL-L-7830. Light, Navigational Boundary and Obstruction Markers.
(b) FAA Specification L-810. Specification for Obstruction Light.
Chap. 5 Paz. 15 Page 21
AC 70/7460-1B 1 Oct 72
(5) Covers for Aeronautical Lights. Military Specification MIL-C-7989. Covers; Light-transmitting (for Aeronautical Lights).
High Intensity White Obstruction Lighting System.
Specification. The high intensity white lighting system referred to in the standards set forth in this publication should conform with the applicable provisions of FAA/DOD Specification L-856, High Intensity Obstruction Lighting
(2) Availability of Specifications. FAA/DOD Specification L-856 is contained in the Federal Aviation Administration Advisory Circular No. 150/5345-43A. Copies of this advisory circular . obtained free of charge from the Department of Transportation, Distribution Unit, IAD-484.3, Washington, D. C. 20591.
(3) Manufacturers. The names of qualified manufacturers and a description of their equipment will be included in the Federal Aviation Administration Advisory Circular No. 150/ Distribution Unit, IAD-484.3, Washington, D. C. 20590. 5345-1C, Approved Airport Lighting Equipment. Copies may be obtained free of charge from the Department of Transportation? * ZZ chap. - Par. 10
1'Oct 72 AC 70/7460-18
c. RECOMMENDED LAMP EQUIPMENT Multiple Circuits Volts Average Typical or Rated Lab. Approx. Specifications Service Watts Amps. Bulb Base Life (Hours) Lumens FAA MIL Double & 125 120V A-21 Md. Pf. 6,000 1,220 Single L-7830 Obstruction 116 120V A-21 Md, Scr 6,000 1,260 L-810 L-7830 Lights Airport 1,000 120V I-20 Mg. Bip. 500 20,500 291 Beacon 1,200 115V T-20 MB. Bip. 750 27,500 L-7158 Code 700 120V PS-40 Mg. Pf. 6,000 11,200 I-6273 Beacon 620 120V PS-40 Mg. Pf. 3,000 11,200 446 L-6273 Intensity High 480V 240V I-856 White 120V Obstruction Lights Series Circuit Obstruction 6,6A A-21 Md. Pf. 2,000 1,020 L-810 L-7830 Lights Copies of military specifications may be obtained by contacting Armed Service Electro-Standards Agency, Fort Monmouth, New Jersey 07703 oI the Naval Air Systems Command, Department of the Navy, 1411 Jefferson Davis Highway, Arlington, Virginia 20360. Copies of specifications and information concerning Military and Federal specifications may be obtained from Federal Aviation Administration, Washington, D. C. 20591.
Chap. 5 Par. 16 Page 23 (and 24)
1 Oct 72 AC 70/7460-1B CHAPTER 6. STANDARDS FOR LIGHTING OBSTRUCTIONS TO AIR NAVIGATION WITH
AVIATION RED OBSTRUCTION LIGHTS
17. PURPOSE. To provide the specifications for red obstruction lights to be placed on obstructions to air navigation.
*18. APPLICATION. The general specifications which follow apply to the obstruction lighting of buildings, towers, smokestacks and similar obstructions, except transmission lines and their support structures.
a. For Towers, Smokestacks and Similar Obstructions of all Heights.
There should be installed at the top for near the top it a smokestack) of the obstruction, in a manner to insure unobstructed visibility of at least one beacon from aircraft at any normal angle of approach, one, or more if required, flashing 300mm electric code.
beacon(s), each equipped with two lamps and aviation red color filters. The two lamps of the beacon should burn simultaneously and each lamp should be at least 500 watts. (See recommended lamp equipment chart.)
(1) If the obstruction is skeletal by nature, such as a tower, and a rod or other construction of not more than 20 feet in height and incapable of supporting this beacon is mounted on top of the obstruction and it is determined that this additional construction does not permit unobstructed visibility of a single code beacon from any normal angle of approach, there should be installed two such beacons properly positioned to permit unobstructed viewing.
If the obstruction is solid by nature, such as a smokestack, there should be installed two or more such beacons placed at regular intervals on the horizontal plane.
b. For Towers, Smokestacks and Similar Obstructions of all Heights.
At the top of certain obstructions and at selected levels on other obstructions, there should be installed two or more lights, each light consisting of a lamp of at least 100 watts, enclosed aviation red obstruction light globe. These lights should be placed at regular intervals on the horizontal plane in a manner to insure unobstructed visibility of one or more lights on each level from aircraft at any normal angle of approach, Chap. 6 Par. 17 Page 25
AC 70/7460-1B 1 Oct 72 *
(1) If the structure is skeletal by nature, such as a tower, two be placed on diagonally or diametrically opposite positions lights should be installed at each level. Each light should of the obstruction and mounted so as to insure unobstructed visibility of at least one light. In case of a triangular or the obstruction at each level. this level. a light should be installed on each corner of the tower at ground, lights should be installed on each outside corner of rectangular shaped tower, the lights should be mounted so as o insure unobstructed visibility of at least one light, or On towers more than 450 feet in height above
(2) If the obstruction is solid by nature, such as a smokestack, These lights should be placed at regular intervals on the there should be installed at each level at least three lights.
horizontal plane in a manner to insure unobstructed view of at least two lights on each level.
c_ Feet in Overall Height. For Towers, one or more similar flashing code beacons should be installed in Smokestacks and Similar Obstructions more than 450 At selected levels other than the cop, ity of them from aircraft at any normal angle of approach. such a position on the obstruction to insure unobstructed visibil-
(1) If the obstruction is skeletal by nature, such as a tower, the beacon should be installed within the structure proper so that the structural members will not impair its visibility. In the beacons. event this is not possible, there should be installed two such Each beacon should be mounted on the outside of at the prescribed height, diagonally opposite corners on opposite sides of the structure
(2) If the obstruction is solid by nature, such as a smokestack, two or more beacons should be installed at regular intervals on the horizontal plane in a manner to insure unobstructed visibility of at least one beacon at each level.
19. SPECIFICATIONS.
a. Towers, Poles, and Similar Obstructions. When the height of the particular obstruction above ground, or water if so situated, is:
(1) Not more than 150 feet: At the top apply 18b(1).
(2) More than 150 feet but not more than 300 feet:
(a) At the top apply 18a(1).
(b) At midpoint of the overall height apply 18b(1).
Page 26 Chap. 6 Par. 18
1 Oct 72 AC 70/7460-18
(3) More than 300 feet but not more than 450 feet:
(a) At the top apply 18a(1).
(b) At approximately two-thirds and one-third of the overall height apply 18b(1).
(4) More than 450 feet but not more than 600 feet:
(a) At the top apply 18a(1).
(b) At approximately one-half of the overall height apply 18c (1).
(c) At approximately three-fourths and one-fourth of the overall height apply 18b (1).
(5) More than 600 feet but not more than 750 feet:
(a) At the top apply 18a(1).
(b) At approximately two-fifths of the overall height apply 18c (1).
(c) At approximately four-fifths, three-fifths, and one-fifth of the overall height apply 18b(1).
More than 750 feet but not more than 900 feet:
(a) At the top apply 18a(1).
(b) At approximately two-thirds and one-third of the overall height apply 18c(1).
(c) At approximately five-sixths, one-half, and one-sixth of the overall height apply 18b(1).
(7) More than 900 feet but not more than 1050 feet:
At the top apply 18a(1).
(b) At approximately four-sevenths and two-sevenths of the overall height apply 18c(1).
At approximately six-sevenths, five-sevenths, threesevenths and one-seventh of the overall height apply 18b (1).
(8) More than 1050 feet but not more than 1200 feet:
At the top apply 18a(1).
At approximately three-fourths, one-half, and one-fourth of the overall height apply 18c(1).
At approximately seven-eighths, five-eighths, threeeighths, and one-eighth of the overall height apply 18b (1).
Chap. 6 Par. 19 Page 27