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Remote Pilot – Small Unmanned Aircraft Systems Study Guide 67
decision to make the flight. Although NOTAMs contain information such as taxiway and runway
closures, construction, communications, changes in status of navigational aids, and other
information essential to planned en route, terminal, or landing operations, a remote pilot can use
this information to help them make an informed decision about where and when to operate their
small UA. Exercise good judgment and common sense by carefully regarding the information readily
available in NOTAMs.
Prior to any flight, pilots should check for any NOTAMs that could affect their intended flight. For
more information on NOTAMs, refer back to Chapter 2, “Airspace Classification, Operating
Requirements, and Flight Restrictions,” of this study guide.
Automated Terminal Information Service (ATIS)
The Automated Terminal Information Service (ATIS) is a recording of the local weather conditions
and other pertinent non-control information broadcast on a local frequency in a looped format. It is
normally updated once per hour but is updated more often when changing local conditions warrant.
Important information is broadcast on ATIS including weather, runways in use, specific ATC
procedures, and any airport construction activity that could affect taxi planning.
When the ATIS is recorded, it is given a code. This code is changed with every ATIS update. For
example, ATIS Alpha is replaced by ATIS Bravo. The next hour, ATIS Charlie is recorded, followed by
ATIS Delta and progresses down the alphabet.
Aeronautical Charts
An aeronautical chart is the road map for a pilot. The chart provides information that allows remote
pilots to obtain information about the areas where they intend to operate. The two aeronautical
charts used by VFR pilots are:
• Sectional
• VFR Terminal Area
A free catalog listing aeronautical charts and related publications including prices and instructions
for ordering is available at the Aeronautical Navigation Products website: www.aeronav.faa.gov.
Sectional Charts
Sectional charts are the most common charts used by pilots today. The charts have a scale of
1:500,000 (1 inch = 6.86 nautical miles (NM) or approximately 8 statute miles (SM)), which allows
for more detailed information to be included on the chart.
The charts provide an abundance of information, including airport data, navigational aids, airspace,
and topography. Figure 11-2 is an excerpt from the legend of a sectional chart. By referring to the
chart legend, a pilot can interpret most of the information on the chart. A pilot should also check
the chart for other legend information, which includes air traffic control (ATC) frequencies and
information on airspace. These charts are revised semiannually except for some areas outside the
conterminous United States where they are revised annually.
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Figure 11-2. Sectional chart and legend.
Latitude and Longitude (Meridians and Parallels)
The equator is an imaginary circle equidistant from the
poles of the Earth. Circles parallel to the equator (lines
running east and west) are parallels of latitude. They are
used to measure degrees of latitude north (N) or south
(S) of the equator. The ang ular distance from the
equator to the pole is one -fourth of a circle or 90°. The
48 conterminous states of the United States are located
between 25° and 49° N latitude. The arrows in
Figure 11-3 labeled “Latitude” point to lines of latitude.
Meridians of longitude are drawn from the North Pole to
the South Pole and are at right angles to the Equator.
The “Prime Meridian,” which passes through Greenwich,
England, is used as the zero line from which
measurements are made in degrees east (E) and west
(W) to 18 0°. The 48 conterminous states of the United
Figure 11-3. Meridians and parallels—the basis of
measuring time, distance, and direction.
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States are between 67° and 125° W longitude. The arrows in Figure 11-3 labeled “Longitude” point to
lines of longitude.
Any specific geographical point can be located by reference to its longitude and latitude. Washington,
D.C., for example, is approximately 39° N latitude, 77° W longitude. Chicago is approximately 42° N
latitude, 88° W longitude.
Variation
Variation is the angle between true north ( TN) and
magnetic north (MN). It is expressed as east
variation or west variation depending upon
whether MN is to the east or west of TN.
The north magnetic pole is located close to 71° N
latitude, 96° W longitude and is about 1,300 miles
from the geographic or true north pole, as
indicated in Figure 11-4. If the Ear th were
uniformly magnetized, the compass needle would
point toward the magnetic pole, in which case the
variation between TN (as shown by the
geographical meridians) and MN (as shown by the
magnetic meridians) could be measured at any
intersection of the meridians.
Actually, the Earth is not uniformly magnetized. In
the United States, the needle usually points in the
general direction of the magnetic pole, but it may
vary in certain geographical localities by many
degrees. Consequently, the exact amount of
variation at thousands of selected locations in the
United States has been carefully determined. The
amount and the direction of variation, which
change slightly from time to time, are shown on
most aeronautical charts as broken magenta lines
called isogonic lines t hat connect points of equal
magnetic variation. (The line connecting points at
which there is no variation between TN and MN is
the agonic line.) An isogonic chart is shown in
Figure 11-5. Minor bends and turns in the isogonic
and agonic lines are caused b y unusual geological
conditions affecting magnetic forces in these areas.
Antenna Towers
Extreme caution should be exercised when flying less
than 2,000 feet AGL because of numerous ske letal
structures, such as radio and television antenna
towers, that exceed 1,000 feet AGL with some
Figure 11-4. Magnetic meridians are in red while the lines of
longitude and latitude are in blue. From these lines of variation
(magnetic meridians), on can determine the effect of local
magnetic variations on a magnetic compass.
Figure 11-5. Note the agonic line where magnetic variation is
zero.
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extending higher than 2,000 feet AGL. Most skeletal structures are supported by guy wires which are
very difficult to see in good weather and can be invisible at dusk or during periods of reduced visibility.
These wires can extend about 1,500 feet horizontally from a structure; therefore, all skeletal structures
should be avoided horizontally by at least 2,000 feet.
Additionally, new towers may not be on your current chart because the information was not received
prior to the printing of the chart.
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Chapter 12:
Maintenance and Preflight Inspection Procedures
Maintenance and Preflight Inspection Procedures can be found in chapter 7 of Advisory Circular 107-2.
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