AIM

8/15/19

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Navigation Aids

(b)

GPS receivers used for VFR navigation

vary from fully integrated IFR/VFR installation used
to support VFR operations to hand

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held devices.

Pilots must understand the limitations of the receivers
prior to using in flight to avoid misusing navigation
information. (See TBL 1

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6.) Most receivers are

not intuitive. The pilot must learn the various
keystrokes, knob functions, and displays that are
used in the operation of the receiver. Some
manufacturers provide computer

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based tutorials or

simulations of their receivers that pilots can use to
become familiar with operating the equipment.

(c)

When using GPS for VFR operations,

RAIM capability, database currency, and antenna
location are critical areas of concern.

(1)

RAIM Capability. VFR GPS panel

mount receivers and hand

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held units have no RAIM

alerting capability. This prevents the pilot from being
alerted to the loss of the required number of satellites
in view, or the detection of a position error. Pilots
should use a systematic cross

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check with other

navigation techniques to verify position. Be
suspicious of the GPS position if a disagreement
exists between the two positions.

(2)

Database Currency. Check the curren-

cy of the database.  Databases must be updated for
IFR operations and should be updated for all other
operations. However, there is no requirement for
databases to be updated for VFR navigation. It is not
recommended to use a moving map with an outdated
database in and around critical airspace. Pilots using
an outdated database should verify waypoints using
current aeronautical products; for example, Chart
Supplement U.S., Sectional Chart, or En Route
Chart.

(3)

Antenna Location. The antenna loca-

tion for GPS receivers used for IFR and VFR
operations may differ. VFR antennae are typically
placed for convenience more than performance,
while IFR installations ensure a clear view is
provided with the satellites. Antennae not providing
a clear view have a greater opportunity to lose the
satellite navigational signal. This is especially true
in the case of hand

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held GPS receivers. Typically,

suction cups are used to place the GPS antennas on
the inside of cockpit windows. While this method has
great utility, the antenna location is limited to the
cockpit or cabin which rarely provides a clear view
of all available satellites.  Consequently, signal losses

may occur due to aircraft structure blocking satellite
signals, causing a loss of navigation capability. These
losses, coupled with a lack of RAIM capability, could
present erroneous position and navigation informa-
tion with no warning to the pilot. While the use of a
hand

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held GPS for VFR operations is not limited by

regulation, modification of the aircraft, such as
installing a panel

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 or  yoke

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mounted holder, is

governed by 14 CFR Part 43. Consult with your
mechanic to ensure compliance with the regulation
and safe installation.

(d)

Do not solely rely on GPS for VFR

navigation. No design standard of accuracy or
integrity is used for a VFR GPS receiver. VFR GPS
receivers should be used in conjunction with other
forms of navigation during VFR operations to ensure
a correct route of flight is maintained. Minimize
head

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down time in the aircraft by being familiar with

your GPS receiver’s operation and by keeping eyes
outside scanning for traffic, terrain, and obstacles.

(e) VFR Waypoints

(1)

VFR waypoints provide VFR pilots

with a supplementary tool to assist with position
awareness while navigating visually in aircraft
equipped with area navigation receivers. VFR
waypoints should be used as a tool to supplement
current navigation procedures. The uses of VFR
waypoints include providing navigational aids for
pilots unfamiliar with an area, waypoint definition of
existing reporting points, enhanced navigation in and
around Class B and Class C airspace, and enhanced
navigation around Special Use Airspace. VFR pilots
should rely on appropriate and current aeronautical
charts published specifically for visual navigation.  If
operating in a terminal area, pilots should take
advantage of the Terminal Area Chart available for
that area, if published. The use of VFR waypoints
does not relieve the pilot of any responsibility to
comply with the operational requirements of 14 CFR
Part 91.

(2)

VFR waypoint names (for computer

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entry and flight plans) consist of five letters
beginning with the letters “VP” and are retrievable
from navigation databases. The VFR waypoint
names are not intended to be pronounceable, and they
are not for use in ATC communications. On VFR
charts, stand

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alone VFR waypoints will be portrayed

using the same four

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point star symbol used for IFR

waypoints. VFR waypoints collocated with visual
check points on the chart will be identified by small