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(2) However, in many cases, the database
drives a moving map display which indicates Special
Use Airspace and the various classes of airspace, in
addition to other operational information. Without a
current database the moving map display may be
outdated and offer erroneous information to VFR
pilots wishing to fly around critical airspace areas,
such as a Restricted Area or a Class B airspace
segment. Numerous pilots have ventured into
airspace they were trying to avoid by using an
outdated database. If you don't have a current
database in the receiver, disregard the moving map
display for critical navigation decisions.
(3) In addition, waypoints are added,
removed, relocated, or re-named as required to meet
operational needs. When using GPS to navigate
relative to a named fix, a current database must be
used to properly locate a named waypoint. Without
the update, it is the pilot's responsibility to verify the
waypoint location referencing to an official current
source, such as the Airport/Facility Directory,
Sectional Chart, or En Route Chart.
(c) Antenna Location
(1) In many VFR installations of GPS
receivers, antenna location is more a matter of
convenience than performance. In IFR installations,
care is exercised to ensure that an adequate clear view
is provided for the antenna to see satellites. If an
alternate location is used, some portion of the aircraft
may block the view of the antenna, causing a greater
opportunity to lose navigation signal.
(2) This is especially true in the case of
hand-helds. The use of hand-held receivers for VFR
operations is a growing trend, especially among
rental pilots. 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 only and is
rarely optimized to provide a clear view of available
satellites. Consequently, signal losses may occur in
certain situations of aircraft-satellite geometry,
causing a loss of navigation signal. These losses,
coupled with a lack of RAIM capability, could
present erroneous position and navigation informa-
tion with no warning to the pilot.
(3) While the use of a hand-held GPS for
VFR operations is not limited by regulation,
modification of the aircraft, such as installing a
panel- or yoke-mounted holder, is governed by
14_CFR Part 43. Consult with your mechanic to
ensure compliance with the regulation, and a safe
installation. |
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