2-2-1.
Aeronautical Light Beacons
a. An
aeronautical light beacon is a visual NAVAID displaying
flashes of white and/or colored light to indicate the
location of an airport, a heliport, a landmark, a certain
point of a Federal airway in mountainous terrain, or an
obstruction. The light used may be a rotating beacon or one
or more flashing lights. The flashing lights may be
supplemented by steady burning lights of lesser intensity.
b. The color
or color combination displayed by a particular beacon and/or
its auxiliary lights tell whether the beacon is indicating a
landing place, landmark, point of the Federal airways, or an
obstruction. Coded flashes of the auxiliary lights, if
employed, further identify the beacon site.
2-2-2.
Code Beacons and Course Lights
a. Code Beacons.
The code beacon, which can be seen from all directions,
is used to identify airports and landmarks. The code beacon
flashes the three or four character airport identifier in
International Morse Code six to eight times per minute.
Green flashes are displayed for land airports while yellow
flashes indicate water airports.
b. Course Lights.
The course light, which can be seen clearly from only
one direction, is used only with rotating beacons of the
Federal Airway System: two course lights, back to
back, direct coded flashing beams of light in either
direction along the course of airway.
NOTE-
Airway beacons are remnants of the "lighted" airways which
antedated the present electronically equipped federal
airways system. Only a few of these beacons exist today to
mark airway segments in remote mountain areas. Flashes in
Morse code identify the beacon site.
2-2-3.
Obstruction Lights
a.
Obstructions are marked/lighted to warn airmen of their
presence during daytime and nighttime conditions. They may
be marked/lighted in any of the following combinations:
1. Aviation Red
Obstruction Lights. Flashing aviation red beacons
(20 to 40 flashes per minute) and steady burning aviation
red lights during nighttime operation. Aviation orange and
white paint is used for daytime marking.
2. Medium
Intensity Flashing White Obstruction Lights.
Medium intensity flashing white obstruction lights
may be used during daytime and twilight with automatically
selected reduced intensity for nighttime operation. When
this system is used on structures 500 feet (153m) AGL or
less in height, other methods of marking and lighting the
structure may be omitted. Aviation orange and white paint is
always required for daytime marking on structures exceeding
500 feet (153m) AGL. This system is not normally installed
on structures less than 200 feet (61m) AGL.
3. High Intensity
White Obstruction Lights. Flashing high intensity
white lights during daytime with reduced intensity for
twilight and nighttime operation. When this type system is
used, the marking of structures with red obstruction lights
and aviation orange and white paint may be omitted.
4. Dual
Lighting. A combination of flashing aviation red
beacons and steady burning aviation red lights for nighttime
operation and flashing high intensity white lights for
daytime operation. Aviation orange and white paint may be
omitted.
5. Catenary
Lighting. Lighted markers are available for
increased night conspicuity of high-voltage (69KV or higher)
transmission line catenary wires. Lighted markers provide
conspicuity both day and night.
b. Medium
intensity omnidirectional flashing white lighting system
provides conspicuity both day and night on catenary support
structures. The unique sequential/simultaneous flashing
light system alerts pilots of the associated catenary wires.
c. High
intensity flashing white lights are being used to identify
some supporting structures of overhead transmission lines
located across rivers, chasms, gorges, etc. These lights
flash in a middle, top, lower light sequence at
approximately 60 flashes per minute. The top light is
normally installed near the top of the supporting structure,
while the lower light indicates the approximate lower
portion of the wire span. The lights are beamed towards the
companion structure and identify the area of the wire span.
d.
High intensity flashing white lights are also employed
to identify tall structures, such as chimneys and towers, as
obstructions to air navigation. The lights provide a 360
degree coverage about the structure at 40 flashes per minute
and consist of from one to seven levels of lights depending
upon the height of the structure. Where more than one level
is used the vertical banks flash simultaneously.
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