2. Air Navigation and Obstruction Lighting
Aeronautical Light Beacons
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.
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.
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
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.
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.
Obstructions are marked/lighted to warn
airmen of their presence during daytime and nighttime
conditions. They may be marked/lighted in any of the
1. Aviation Red
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
night-time 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
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.
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.
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.