AIM
8/15/19
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61
Arrival Procedures
lighting. Additionally, there are plans to replace
incandescent lamps with LEDs in approach lighting
systems. Pilots should be aware that LED lights
cannot be sensed by infrared
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based EFVSs. Further,
the FAA does not currently collect or disseminate
information about where LED lighting is installed.
l. Other Vision Systems.
An Enhanced Vision
System (EVS) does not meet the requirements of an
EFVS. An EVS may present the sensor image on a
head
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down display and may not be able to present the
image and flight symbology in the same scale and
alignment as the outside view. An EVS can also use
a HUD as its display element, yet still not meet the
regulatory requirements for an EFVS. While an EVS
that uses a head
−
down display or HUD may provide
situation awareness to the pilot, it does not meet the
operating requirements for an EFVS. Consequently,
a pilot cannot use an EVS in lieu of natural vision to
descend below DA/DH or MDA. Unlike an EFVS, a
Synthetic Vision System (SVS) or Synthetic Vision
Guidance System (SVGS) does not provide a
real
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time sensor image of the outside scene and also
does not meet the equipment requirements for EFVS
operations. A pilot cannot use a synthetic vision
image on a head
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up or a head
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down display in lieu
of natural vision to descend below DA/DH or MDA.
An EFVS can, however, be integrated with an SVS,
also known as a Combined Vision System (CVS). A
CVS can be used to conduct EFVS operations if all of
the requirements for an EFVS are satisfied and the
SVS image does not interfere with the pilot’s ability
to see the external scene, to identify the required
visual references, or to see the sensor image.
m. Additional Information.
Operational criteria
for EFVS can be found in Advisory Circular (AC)
90
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106, Enhanced Flight Vision Systems, and
airworthiness criteria for EFVS can be found in
AC 20
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167, Airworthiness Approval of Enhanced
Vision System, Synthetic Vision System, Combined
Vision System, and Enhanced Flight Vision System
Equipment.
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23. Visual Approach
a.
A visual approach is conducted on an IFR flight
plan and authorizes a pilot to proceed visually and
clear of clouds to the airport. The pilot must have
either the airport or the preceding identified aircraft
in sight. This approach must be authorized and
controlled by the appropriate air traffic control
facility. Reported weather at the airport must have a
ceiling at or above 1,000 feet and visibility 3 miles or
greater. ATC may authorize this type approach when
it will be operationally beneficial. Visual approaches
are an IFR procedure conducted under IFR in visual
meteorological conditions. Cloud clearance require-
ments of 14 CFR Section 91.155 are not applicable,
unless required by operation specifications.
b. Operating to an Airport Without Weather
Reporting Service.
ATC will advise the pilot when
weather is not available at the destination airport.
ATC may initiate a visual approach provided there is
a reasonable assurance that weather at the airport is a
ceiling at or above 1,000 feet and visibility 3 miles or
greater (e.g., area weather reports, PIREPs, etc.).
c. Operating to an Airport With an Operating
Control Tower.
Aircraft may be authorized to
conduct a visual approach to one runway while other
aircraft are conducting IFR or VFR approaches to
another parallel, intersecting, or converging runway.
When operating to airports with parallel runways
separated by less than 2,500 feet, the succeeding
aircraft must report sighting the preceding aircraft
unless standard separation is being provided by ATC.
When operating to parallel runways separated by at
least 2,500 feet but less than 4,300 feet, controllers
will clear/vector aircraft to the final at an angle not
greater than 30 degrees unless radar, vertical, or
visual separation is provided during the turn
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on. The
purpose of the 30 degree intercept angle is to reduce
the potential for overshoots of the final and to
preclude side
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by
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side operations with one or both
aircraft in a belly
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up configuration during the
turn
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on. Once the aircraft are established within
30 degrees of final, or on the final, these operations
may be conducted simultaneously. When the parallel
runways are separated by 4,300 feet or more, or
intersecting/converging runways are in use, ATC
may authorize a visual approach after advising all
aircraft involved that other aircraft are conducting
operations to the other runway. This may be
accomplished through use of the ATIS.
d. Separation Responsibilities.
If the pilot has
the airport in sight but cannot see the aircraft to be
followed, ATC may clear the aircraft for a visual
approach; however, ATC retains both separation and
wake vortex separation responsibility. When visually
following a preceding aircraft, acceptance of the
visual approach clearance constitutes acceptance of