SUBPART I
Visual Aids for Denoting Obstacles
139.329 Visual Aids for denoting
obstacles
(a) Objects
to be marked and/or lighted:
Note:
The marking and/or lighting of obstacles is intended to reduce hazards to
aircraft by indicating the presence of the obstacles. It does not necessarily
reduce operating limitations which may be imposed by an obstacle.
(1) A fixed obstacle that extends
above a take-off climb surface within 3000 m of the inner edge of the take-off
climb surface should be marked and, if the runway is used at night, lighted,
except that:
(i) Such marking and lighting
may be omitted when the obstacle is shielded by another fixed obstacle;
(ii) The marking may be omitted
when the obstacle is lighted by medium-intensity obstacle lights, Type A, by
day and its height above the level of the surrounding ground does not exceed
150 m;
(iii) The marking may be omitted
when the obstacle is lighted by high-intensity obstacle lights by day; and
(iv) The lighting may be omitted
where the obstacle is a lighthouse and an aeronautical study indicates the
lighthouse light to be sufficient.
(2) A fixed object, other than an
obstacle, adjacent to a take-off climb surface should be marked and, if the
runway is used at night, lighted if such marking and lighting is considered
necessary to ensure its avoidance, except that the marking may be omitted when:
(i) The object is lighted by
medium-intensity obstacle lights, Type A, by day and its height above the level
of the surrounding ground does not exceed 150m; or
(ii) The object is lighted by
high-intensity obstacle lights by day.
(3) A fixed obstacle that extends
above an approach or transitional surface within 3000m of the inner edge of the
approach surface shall be marked and, if the runway is used at night, lighted, except
that:
(i) Such marking and lighting
may be omitted when the obstacle is shielded by another fixed obstacle;
(ii) The marking may be omitted
when the obstacle is lighted by medium-intensity obstacle lights, Type A, by
day and its height above the level of the surrounding ground does not exceed
150 m;
(iii) The marking may be omitted
when the obstacle is lighted by high-intensity obstacle lights by day; and
(iv) The lighting may be omitted
where the obstacle is a lighthouse and an aeronautical study indicates the
lighthouse light to be sufficient.
(4) A fixed obstacle above a
horizontal surface should be marked and, if the aerodrome is used at night,
lighted except that:
(i) Such marking and lighting may
be omitted when:
(A) The obstacle is shielded by
another fixed obstacle; or
(B) For a circuit extensively
obstructed by immovable objects or terrain, procedures have been established to
ensure safe vertical clearance below prescribed flight paths; or
(C) An aeronautical study shows
the obstacle not to be of operational significance;
(ii) The marking may be omitted
when the obstacle is lighted by medium-intensity obstacle lights, Type A, by
day and its height above the level of the surrounding ground does not exceed
150 m;
(iii) The marking may be omitted
when the obstacle is lighted by high-intensity obstacle lights by day; and
(iv) The lighting may be omitted
where the obstacle is a lighthouse and an aeronautical study indicates the
lighthouse light to be sufficient.
(5) A fixed object that extends above an obstacle protection surface
shall be marked and, if the runway is used at night, lighted.
Note: See .323(e) for information on the obstacle protection surface
(6) Vehicles and other mobile
objects, excluding aircraft, on the movement area of an aerodrome are obstacles
and shall be marked and, if the vehicles and aerodrome are used at night or in
conditions of low visibility, lighted, except that aircraft servicing equipment
and vehicles used only on aprons may be exempt.
(7) Elevated aeronautical ground
lights within the movement area shall be marked so as to be conspicuous by day.
Obstacle lights shall not be installed on elevated ground lights or signs in
the movement area.
(8) All obstacles within the
distance specified in Table 3-1, column 11 or 12, from the centre line of a
taxiway, an apron taxiway or aircraft stand taxilane shall be marked and, if
the taxiway, apron taxiway or aircraft stand taxilane is used at night,
lighted.
(9) Obstacles in accordance with
.317(c)(2) should be marked and lighted, except that the marking may be omitted
when the obstacle is lighted by high- intensity obstacle lights by day.
(10) Overhead wires, cables, etc.,
crossing a river, valley or highway
should be marked and their supporting towers marked and lighted if an aeronautical
study indicates that the wires or cables could constitute a hazard to aircraft,
except that the marking of the supporting towers may be omitted when they are
lighted by high-intensity obstacle lights by day.
(11) When it has been determined
that an overhead wire, cable, etc., needs to be marked but it is not
practicable to install markers on the wire, cable, etc., then high-intensity
obstacle lights, Type B, should be provided on their supporting towers.
(b) Marking
of objects:
(1) General: All fixed objects to
be marked shall, whenever practicable, be coloured, but if this is not
practicable, markers or flags shall be displayed on or above them, except that
objects that are sufficiently conspicuous by their shape, size or colour need
not be otherwise marked.
(2) All mobile objects to be
marked shall be coloured or display flags.
(3) Use of colours: An object
should be coloured to show a chequered pattern if it has essentially unbroken
surfaces and its projection on any vertical plane equals or exceeds 4.5 m in
both dimensions. The pattern should consist of rectangles of not less than 1.5
m and not more than 3 m on a side, the corners being of the darker colour. The
colours of the pattern should contrast each with the other and with the
background against which they will be seen. Orange and white or alternatively
red and white should be used, except where such colours merge with the
background. (See Figure 6-1.)
Figure 6-1: Basic marking patterns
(4) An object should be coloured
to show alternating contrasting bands if:
(i) It has essentially unbroken
surfaces and has one dimension, horizontal or vertical, greater than 1.5m, and
the other dimension, horizontal or vertical, less than 4.5m; or
(ii) It is of skeletal type with
either a vertical or a horizontal dimension greater than 1.5m.
The
bands should be perpendicular to the longest dimension and have a width
approximately 1/7 of the longest dimension or 30 m, whichever is less. The
colours of the bands should contrast with the background against which they
will be seen. Orange and white should be used, except where such colours are
not conspicuous when viewed against the background. The bands on the
extremities of the object should be of the darker colour. (See Figures 6-1 and 6-2.)
Note:
Table 6-1 shows a formula for determining band widths and for having an odd
number of bands, thus permitting both the top and bottom bands to be of the
darker colour.
(5) An object should be coloured
in a single conspicuous colour if its projection on any vertical plane has both
dimensions less than 1.5m.
Note:
Against some backgrounds it may be found necessary to use a different colour
from orange or red to obtain sufficient contrast.
(6) When mobile objects are
marked by colour, a single conspicuous colour, preferably red or yellowish
green for emergency vehicles and yellow for service vehicles should be used.
Table 6-1. Marking band widths
|
Longest dimension |
||
|
Greater than |
Not exceeding |
Band width |
|
1.5 m |
210 m |
1/7
of longest dimension |
|
210 m |
270 m |
1/9
of longest dimension |
|
270 m |
330 m |
1/11 of longest dimension |
|
330 m |
390 m |
1/13 of longest dimension |
|
390 m |
450 m |
1/15 of longest dimension |
|
450 m |
510 m |
1/17 of longest dimension |
|
510 m |
570 m |
1/19 of longest dimension |
|
570 m |
630 m |
1/21 of longest dimension |
(7) Use of markers: Markers
displayed on or adjacent to objects shall be located in conspicuous positions
so as to retain the general definition of the object and shall be recognizable
in clear weather from a distance of at least 1 000 m for an object to be viewed
from the air and 300 m for an object to be viewed from the ground in all
directions in which an aircraft is likely to approach the object. The shape of
markers shall be distinctive to the extent necessary to ensure that they are
not mistaken for markers employed to convey other information, and they shall
be such that the hazard presented by the object they mark is not increased.
(8) A marker displayed on an
overhead wire, cable, etc., should be spherical and have a diameter of not less
than 60 cm.
(9) The spacing between two
consecutive markers or between a marker and a supporting tower should be
appropriate to the diameter of the marker, but in no case should the spacing
exceed:
(i) 30 m where the marker
diameter is 60 cm progressively increasing with the diameter of the marker to
(ii) 35 m where the marker
diameter is 80 cm and further progressively increasing to a maximum of
(iii) 40 m where the marker
diameter is of at least 130 cm.
Where
multiple wires, cables, etc. are involved, a marker should be located not lower
than the level of the highest wire at the point marked.
(10) A marker should be of one
colour. When installed, white and red, or white and orange markers should be
displayed alternately. The colour selected should contrast with the background
against which it will be seen.
(11) Use of flags: Flags used to
mark objects shall be displayed around, on top of, or around the highest edge
of, the object. When flags are used to mark extensive objects or groups of
closely spaced objects, they shall be displayed at least every 15m. Flags shall
not increase the hazard presented by the object they mark.
(12) Flags used to mark fixed
objects shall not be less than 0.6m square and flags used to mark mobile
objects, not less than 0.9m square.
(13) Flags used to mark fixed
objects should be orange in colour or a combination of two triangular sections,
one orange and the other white, or one red and the other white, except that
where such colours merge with the background, other conspicuous colours should
be used.
(14) Flags used to mark mobile
objects shall consist of a chequered pattern, each square having sides of not
less than 0.3 m. The colours of the pattern shall contrast each with the other
and with the background against which they will be seen. Orange and white or
alternatively red and white shall be used, except where such colours merge with
the background.
(c) Lighting of objects:
(1) Use
of obstacle lights: The presence of objects which must be lighted, as specified
in .329(a), shall be indicated by low-, medium- or high-intensity obstacle
lights, or a combination of such lights.
Note. High-intensity obstacle lights are intended for day use as well as night use. Care is needed to ensure that these lights do not create disconcerting dazzle. Guidance on the design, location and operation of high-intensity obstacle lights is given in EAC 139-12.
(2) Low-intensity
obstacle lights, Type A or B, should be used where the object is a less
extensive one and its height above the surrounding ground is less than 45m.
(3) Where
the use of low-intensity obstacle lights, Type A or B, would be inadequate or
an early special warning is required, then medium- or high-intensity obstacle
lights should be used.
(4) Low-intensity
obstacle lights, Type C, shall be displayed on vehicles and other mobile
objects excluding aircraft.
(5) Low-intensity
obstacle lights, Type D, shall be displayed on follow-me vehicles.
(6) Low-intensity
obstacle lights, Type B, should be used either alone or in combination with
medium-intensity obstacle lights, Type B, in accordance with .329(c)(7).
(7) Medium-intensity obstacle lights,
Type A, B or C, should be used where the object is an extensive one or its
height above the level of the surrounding ground is greater than 45 m.
Medium-intensity obstacle lights, Types A and C, should be used alone, whereas
medium-intensity obstacle lights, Type B, should be used either alone or in
combination with low-intensity obstacle lights, Type B.
Note: A group of trees or buildings is regarded as an extensive object.
Figure 6-2: Examples of marking and lighting of tall structures
(8) High-intensity obstacle lights, Type A, should be used to indicate
the presence of an object if its height above the level of the surrounding
ground exceeds 150 m and an aeronautical study indicates such lights to be
essential for the recognition of the object by day.
(9) High-intensity obstacle
lights, Type B, should be used to indicate the presence of a tower supporting
overhead wires, cables, etc., where:
(i) An aeronautical study
indicates such lights to be essential for the recognition of the presence of
wires, cables, etc.; or
(ii) It has not been found
practicable to install markers on the wires, cables, etc.
(10) Where, in the opinion of the
ECAA, the use of high-intensity obstacle lights, Type A or B, or
medium-intensity obstacle lights, Type A, at night may dazzle pilots in the
vicinity of an aerodrome (within approximately 10 000 m radius) or cause
significant environmental concerns, a dual obstacle lighting system should be
provided. This system should be composed of high-intensity obstacle lights,
Type A or B, or medium-intensity obstacle lights, Type A, as appropriate, for daytime
and twilight use and medium-intensity obstacle lights, Type B or C, for
night-time use.
(11) Location of obstacle lights:
One or more low-, medium- or high-intensity obstacle lights shall be located as
close as practicable to the top of the object. The top lights shall be so
arranged as to at least indicate the points or edges of the object highest in
relation to the obstacle limitation surface.
Note. Recommendations on how a combination of low-, medium-, and/or high-intensity lights on obstacles should be displayed are given in Appendix 6.
(12) In the case of chimney or
other structure of like function, the top lights should be placed sufficiently
below the top so as to minimize contamination by smoke etc. (see Figures 6-2
and 6-3).
(13) In the case of a tower or
antenna structure indicated by high-intensity obstacle lights by day with an
appurtenance, such as a rod or an antenna, greater than 12m where it is not
practicable to locate a high-intensity obstacle light on the top of the
appurtenance, such a light shall be located at the highest practicable point
and, if practicable, a medium-intensity obstacle light, Type A, mounted on the
top.
(14) In the case of an extensive
object or of a group of closely spaced objects, top lights shall be displayed
at least on the points or edges of the objects highest in relation to the
obstacle limitation surface, so as to indicate the general definition and the
extent of the objects. If two or more edges are of the same height, the edge
nearest the landing area shall be marked. Where low-intensity lights are used,
they shall be spaced at longitudinal intervals not exceeding 45 m. Where
medium-intensity lights are used, they shall be spaced at longitudinal
intervals not exceeding 900 m.
(15) When the obstacle limitation
surface concerned is sloping and the highest point above the obstacle
limitation surface is not the highest point of the object, additional obstacle
lights should be placed on the highest point of the object.
(16) Where an object is indicated
by medium-intensity obstacle lights, Type A, and the top of the object is more
than 105m above the level of the surrounding ground or the elevation of tops of
nearby buildings (when the object to be marked is surrounded by buildings),
additional lights shall be provided at intermediate levels. These additional
intermediate lights shall be spaced as equally as practicable, between the top
lights and ground level or the level of tops of nearby buildings, as
appropriate, with the spacing not exceeding 105m (see .329(c)(7)).
(17) Where an object is indicated
by medium-intensity obstacle lights, Type B, and the top of the object is more
than 45 m above the level of the surrounding ground or the elevation of tops of
nearby buildings (when the object to be marked is surrounded by buildings),
additional lights shall be provided at intermediate levels. These additional
intermediate lights shall be alternately low-intensity obstacle lights, Type B,
and medium-intensity obstacle lights, Type B, and shall be spaced as equally as
practicable between the top lights and ground level or the level of tops of
nearby buildings, as appropriate, with the spacing not exceeding 52m.
(18) Where an object is indicated
by medium-intensity obstacle lights, Type C, and the top of the object is more
than 45m above the level of the surrounding ground or the elevation of tops of
nearby buildings (when the object to be marked is surrounded by buildings),
additional lights shall be provided at intermediate levels. These additional
intermediate lights shall be spaced as equally as practicable, between the top
lights and ground level or the level of tops of nearby buildings, as
appropriate, with the spacing not exceeding 52m.
(19) Where high-intensity obstacle
lights, Type A, are used, they shall be spaced at uniform intervals not
exceeding 105 m between the ground level and the top light(s) specified in
.329(c)(11) except that where an object to be marked is surrounded by
buildings, the elevation of the tops of the buildings may be used as the
equivalent of the ground level when determining the number of light levels.
(20) Where high-intensity obstacle
lights, Type B, are used, they shall be located at three levels:
(i) At the top of the tower;
(ii) At the lowest level of the
catenary of the wires or cables; and
(iii) At approximately midway
between these two levels.
Note: In some cases, this may require locating the lights off the tower.
(21) The installation setting
angles for high-intensity obstacle lights, Types A and B, should be in
accordance with Table 6-2.
(22) The number and arrangement of
low-, medium- or high-intensity obstacle lights at each level to be marked
shall be such that the object is indicated from every angle in azimuth. Where a
light is shielded in any direction by another part of the object, or by an
adjacent object, additional lights shall be provided on that object in such a
way as to retain the general definition of the object to be lighted. If the
shielded light does not contribute to the definition of the object to be
lighted, it may be omitted.
(23) Characteristics of
Low-intensity obstacle light: Low-intensity obstacle lights on fixed objects,
Types A and B, shall be fixed-red lights.
(24) Low-intensity obstacle lights,
Types A and B, shall be in accordance with the specifications in Table 6-3.
(25) Low-intensity obstacle lights,
Type C, displayed on vehicles associated with emergency or security shall be
flashing-blue and those displayed on other vehicles shall be flashing-yellow.
(26) Low-intensity obstacle lights,
Type D, displayed on follow-me vehicles shall be flashing-yellow.
(27) Low-intensity
obstacle lights, Types C and D, shall be in accordance with the specifications
in Table 6-3.
Figure 6-3: Lighting of buildings
Table 6-2: Installation setting angles
for high-intensity obstacle lights
|
Height of light unit above terrain |
Angle of the peak of the beam above
the horizontal |
|
greater than 151 m AGL |
0° |
|
122 m to 151 m AGL |
1° |
|
92 m to 122 m AGL |
2° |
|
less than 92 m AGL |
3° |
(28) Low-intensity obstacle lights
on objects with limited mobility such as aerobridges shall be fixed-red. The
intensity of the lights shall be sufficient to ensure conspicuity considering
the intensity of the adjacent lights and the general levels of illumination
against which they would normally be viewed.
Note: See ECAR Part 91 for lights
to be displayed by aircraft.
(29) Low-intensity obstacle lights
on objects with limited mobility shall as a minimum be in accordance with the
specifications for low-intensity obstacle lights, Type A, in Table 6-3.
(30) Characteristics of
Medium-intensity obstacle light: Medium-intensity obstacle lights, Type A,
shall be flashing-white lights, Type B shall be flashing-red lights and Type C
shall be fixed-red lights.
(31) Medium-intensity obstacle
lights, Types A, B and C, shall be in accordance with the specifications in
Table 6-3.
(32) Medium-intensity obstacle
lights, Types A and B, located on an object shall flash simultaneously.
(33) Characteristics of
High-intensity obstacle light: High-intensity obstacle lights, Types A and B,
shall be flashing-white lights.
(34) High-intensity obstacle
lights, Types A and B, shall be in accordance with the specifications in Table
6-3.
(35) High-intensity obstacle
lights, Type A, located on an object shall flash simultaneously.
(36) High-intensity obstacle
lights, Type B, indicating the presence of a tower supporting overhead wires,
cables, etc., should flash sequentially; first the middle light, second the top
light and last, the bottom light. The intervals between flashes of the lights
should approximate the following ratios:
|
Flash interval between |
Ratio of cycle time |
|
middle and top light |
1/13 |
|
top and bottom light |
2/13 |
|
bottom and middle light |
10/13. |
Note: The table below does not include recommended
horizontal beam spreads. .329(c)(22) requires 360° coverage
around an obstacle. Therefore, the number of lights needed to meet this
requirement will depend on the horizontal beam spreads of each light as well as
the shape of the obstacle. Thus, with narrower beam spreads, more lights will
be required.
(a) See .329(c)(25)
(b) Effective intensity, as determined in
accordance EAC 139-12.
(c)
Beam spread is defined as the angle between two directions in a plane for which
the intensity is equal to 50% of the lower tolerance value of the intensity
shown in columns 4, 5 and 6. The beam pattern is not necessarily symmetrical
about the elevation angle at which the peak intensity occurs.
(d)
Elevation (vertical) angles are referenced to the horizontal.
(e)
Intensity at any specified horizontal radial as a percentage of the actual peak
intensity at the same radial when operated at each of the intensities shown in
columns 4, 5 and 6.
(f)
Intensity at any specified horizontal radial as a percentage of the lower
tolerance value of the intensity shown in columns 4, 5 and 6.
(g)
In addition to specified values, lights shall have sufficient intensity to
ensure conspicuity at elevation angles between ± 0° and 50°.
(h)
Peak intensity should be located at approximately 2. 5° vertical.
(i)
Peak intensity should be located at approximately 17° vertical.
Fpm: flashes
per minute; N/A: not
applicable.
Table 6- 3:
Characteristics of obstacle lights
(d) Wind turbines
(1) A wind turbine shall be marked and/or lighted if
it is determined to be an obstacle.
Note.— see 139.317.(c).(1) and 139.317.(c).(2).
(2) Markings:
The rotor blades, nacelle and upper 2/3 of the supporting mast of wind turbines
should be painted white, unless otherwise indicated by an aeronautical study.
(3) Lighting:
When lighting is deemed necessary, medium intensity obstacle lights should be
used. In the case of a wind farm, i.e. a group of two or more wind turbines, it
should be regarded as an extensive object and the lights should be installed:
(i) to identify the perimeter of the wind farm;
(ii) respecting the maximum spacing, in accordance
with 139.329.(c).(14), between the lights along the perimeter, unless a
dedicated assessment shows that a greater spacing can be used;
(iii) so that, where flashing lights are used, they
flash simultaneously; and
(iv) so that, within a wind farm, any wind turbines of
significantly higher elevation are also identified wherever they are located.
(4) The
obstacle lights should be installed on the nacelle in such a manner as to
provide an unobstructed view for aircraft approaching from any direction