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Guide
To SMGCS Features
In order to enhance taxiing
capabilities in low visibility conditions and reduce
the potential for runway incursions, improvements
have been made in signage, lighting, and markings.
In addition to these improvements, Advisory Circular
(AC) 120-57, Surface Movement Guidance and Control
System, more commonly known as SMGCS (acronym
pronounced 'SMIGS'), requires a low visibility taxi
plan for any airport which has takeoff or landing
operations with less than 1,200 feet runway visual
range (RVR) visibility conditions. This plan affects
both air crew and vehicle operators. Taxi routes to
and from the SMGCS runway must be designated and
displayed on a SMGCS Low Visibility Taxi Route
chart.
A brief detail of SMGCS features
is listed below but SMGCS airports may not have all
of these features. For additional SMGCS information
refer to the Aeronautical Information Manual or the
particular airport's SMGCS Low Visibility Taxi Route
chart. |
Stop bars are required at intersections of an
illuminated (centerline lighted) taxiway and an
active runway for operations less than 600 feet RVR.
These lights consist of a row of red unidirectional,
in-pavement lights installed along the holding
position marking. When extinguished by the
controller, they confirm clearance for the pilot or
vehicle operator to enter the runway. Controlled
stop bars operate in conjunction with green
centerline lead-on lights, which extend from the
stop bar location onto the runway.
Normal operation of stop bars
include:
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When ATC issues a clearance to
the pilot to enter the runway they activate a
timer. This action causes the red stop bar to be
extinguished and the green lead-on lights to
illuminate.
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After traveling approximately
150 feet beyond the stop bar, the aircraft or
vehicle activates a sensor. This sensor relights
the red stop bar and extinguishes the first
segment of the lead-on lights between the stop
bar and the sensor. This protects the runway
against inadvertent entry by a trailing aircraft
or vehicle.
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The aircraft then activates
another sensor at approximately 300 feet which
extinguishes the remaining lead-on lights.
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If either sensor is not
activated within a specified time limit, the
stop bar will automatically reset to
"on" and both sets of lead-on lights
will be turned "off."
Should the pilot or vehicle
operator have a discrepancy between the condition of
the stop bar or lead-on lights and the verbal
clearance from the controller, the aircraft or
vehicle shall stop immediately.
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!WARNING!
Pilots
Shall Never Cross An Illuminated Red Stop Bar |
Runway guard lights, either elevated or in-pavement,
will be installed at all taxiways which provide
access to an active runway. They consist of
alternately flashing yellow lights. These lights are
used to denote both the presence of an active runway
and identify the location of a runway holding
position marking. |
Taxiway Centerline lights guide ground traffic under
low visibility conditions and during darkness. These
lights consist of green in-pavement lights. |
ATC will verify the position of aircraft and
vehicles using geographic position markings. The
markings can be used either as hold points or for
position reporting. These checkpoints or "pink
spots" will be outlined with a black and white
circle and be designated with a number, a letter, or
both.
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Three yellow in-pavement clearance bar lights will
be used to denote holding positions for aircraft and
vehicles. When used for hold points, they are
co-located with geographic position markings. |
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Feature
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Description
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Stop
Bar
Lights |
Row of red, in-pavement
lights that when illuminated designate a runway hold
position. NEVER CROSS AN ILLUMINATED RED
STOP BAR. |
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Runway
Guard Lights |
Elevated or in-pavement
yellow flashing lights installed at runway holding
positions. |
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Taxiway
Centerline
Lights |
Green in-pavement lights
to assist taxiing aircraft in darkness and in low
visibility conditions. |
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Clearance
Bar Lights |
In-pavement yellow
lights. When installed with geographic position
markings they indicate designated aircraft or vehicle
hold points. |
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Geographic
Position
Marking
(pink spot) |
Indicates a specific
location on the airport surface. |
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Taxiway
Centerline Marking |
Provides a visual cue to
permit taxiing along a designated path. Marking may be
enhanced on light-colored pavement by outlining with a
black border. |
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