Sectional Chart: An Ultimate Guide To Read & Understand

There’s a lot of information on a Sectional Chart, which can be quite daunting for the uninitiated. But don’t worry; in this blog post, we will guide you through everything you need to know to read and understand Sectional Charts like a pro!

We’ll start by explaining latitude and longitude, then discuss some of the most important terms you’ll see on Sectional Charts. After that, we’ll take a look at different types of airspace and explain what each one means. Finally, we’ll give you a few tips on how to use Sectional Charts when flying!

What are Sectional Charts?

Sectional charts are large-scale maps produced by the National Aeronautical Charting Office (NACO) that show detailed information about a particular airspace area. Pilots use them to plan flights and air traffic controllers direct aircraft.

Sectional charts are divided into a number of different sections, each of which covers a specific area of airspace. The sections are numbered, and each one has a letter assigned to it.

The Sectional Chart is the most important tool for a pilot. It provides information on airspace, airports, navaids or navigational air systems, terrain, and more. In order to fly safely and legally, it is essential that all pilots know how to read and understand a Sectional Chart.

READ: Ground School: Is It Required For Pilots? All You Need To Know

Longitudes and Latitudes

Although many of you are familiar with these two terms, as they have been extensively covered during your school years, it is still essential to cover these basics before moving on. Sectional charts are drawn using a coordinate system based on longitude and latitude. Therefore, to read any map, we make use of these two imaginary lines.

Latitude is a measure of how far north or south of the equator a location is and is measured in degrees. There are 360 degrees of latitude, and each degree can be further divided into 60 minutes.

Imagine a series of parallel lines running east to west around the globe, with the equator being the starting point. These are lines of latitude. The most important latitude is the equator, which is at 0 degrees.

On the other hand, longitude is a measure of how far east or west of the prime meridian a location is. The prime meridian is an imaginary line that runs from the North Pole to the South Pole and passes through Greenwich, England.

Longitude is measured in degrees (just like latitude), but unlike latitude, there are 180 degrees of longitude (as opposed to 360). Lines of longitude run north to south. The prime meridian is the most important line of longitude at 0 degrees. The equator passes through the middle of the prime meridian.

Latitude is measured in degrees north and south of the equator, while longitude is measured in degrees east and west of the prime meridian. Sectional charts are divided into a number of sections, each covering a specific area of airspace. The sections are numbered, and each one has a letter assigned to it.

Latitude and longitude can be used to pinpoint any location on the globe. For example, the coordinates for New York City are 40.71 degrees north latitude and 74.01 degrees west longitude.

This means that if you were to draw a line from the North Pole to New York City, it would be 40.71 degrees long. Similarly, if you were to draw a line from Greenwich, England, to New York City, it would be 74.01 degrees long.

Most Sectional Charts have a scale of either one or two inches equals 50 nautical miles. This means that one inch on the chart represents 50 nautical miles or about 58 statute miles. Two inches on the chart represent 100 nautical miles or about 116 statute miles.

The numbers along the edge of the Sectional Chart tell you the distance, in nautical miles, from a specific point. For example, if the numbers along the edge of the chart say “40”, this means that the point is 40 nautical miles from the reference point.

A quadrant is another term to learn when it comes to reading Sectional Charts. A quadrant is one-fourth of a circle or 90 degrees. Sectional charts are divided into quadrants using the lines of longitude and latitude. Each quadrant is numbered, starting with “NE” for Northeast, “SE” for Southeast, “SW” for Southwest, and “NW” for Northwest.

Now that we’ve reviewed the basics of latitude and longitude let’s discuss some of the most important terms you’ll see on Sectional Charts!

The Sectional Chart is the most important tool for a pilot. It provides information on airspace, airports, navaids or navigational air systems, terrain, and more. To fly safely and legally, it is essential that all pilots know how to read and understand a Sectional Chart.

READ: What Is The Minimum Age To Get A Pilot License?

Airport and Airport Information

Airports in the sectional chart are an important part of pre-flight planning. The symbol identifies the type of airport on the chart and the accompanying information block. There are five types of airports:

• Class B, C, and D Airports have an operational control tower
• Class E Airports that do not have an operational control tower
• Class G Airports which have neither an operational control tower nor Class B, C, D, or E airspace
• Seaports
• Heliports

The information block for each airport on the Sectional Chart will include the following:

• Airport name
• Location identifier
• Field elevation
• Magnetic variation
• Transition altitude
• Type of landing facility

The symbols are also described for your convenience.

Class B, C, and D Airports

These airports have an operational control tower and are depicted on the Sectional Chart with a symbol that looks like a square with a circle in the middle. The information block for these types of airports will also include the airport control tower frequency.

Class E Airports

These airports do not have an operational control tower and are depicted on the Sectional Chart with a symbol that looks like a square. The information block for these types of airports will also include the Common Traffic Advisory Frequency (CTAF).

Class G Airports

These airports have neither an operational control tower nor Class B, C, D, or E airspace and are depicted on the Sectional Chart with a symbol that looks like a circle. The information block for these types of airports will also include the Automated Surface Observing System (ASOS) or UNICOM frequency.

Seaports

Seaports are not typically used by airplane traffic but are included on Sectional Charts for navigational purposes. They are depicted on the Sectional Chart with a symbol that looks like a square with a triangle in the middle.

Heliports

Heliports are airports that are used exclusively by helicopters. They are depicted on the Sectional Chart with a symbol that looks like a circle with an H in the middle. The information block for heliports will also include the helicopter landing pad elevation.

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Military Airports

Military airports are also included on Sectional Charts but are not open to the public. They are depicted with a symbol that looks like a star inside of a square. The information block for military airports will also include the airport restriction and NOTAM information. They are also depicted by abbreviations such as “MIL” or “AFB.”

• Airports with a hard-surfaced runway between 1500′ and 8069′ in length are identified by their runway length. The first number is the length in thousands of feet, and the second number is the length in hundreds of feet. For example, a runway that is 5000′ long would be identified as “50.” A runway that is 12,300′ long would be identified as “123.”

• The names of the airport will also be listed in the information block. The name may be followed by the type of airport, such as “Intl” for international, “Regional” for regional, or “Muni” for municipal. For example, the name of an airport that is 5000′ long and has a control tower would be written as “50CT.” The name of an airport 12,300′ long with no control tower would be “123E.”

• Another concept to keep in mind is the elevation of the airport. The field elevation is the highest point on the airport property and is typically given in feet above mean sea level (MSL). For example, an airport with a field elevation of 100′ MSL would be written as “100.”

• The next item in the information block is the magnetic variation. The magnetic variation is the difference between the true north and the magnetic north. It is given in degrees, with the east being positive and the west being negative. For example, an airport with a magnetic variation of 15°E would be written as “15E.”

• The transition altitude is the altitude at which an aircraft transitions from flying under visual flight rules (VFR) to flying under instrument flight rules (IFR). The transition altitude is typically 4000′ MSL but can be higher or lower depending on the airport. It is given in feet above MSL. For example, an airport with a transition altitude of 4000′ MSL would be written as “4000.”

• Another item in the information block is the runway visual range (RVR). The RVR is the distance that a pilot can see down the runway. It is given in feet and is typically 600′ or more. For example, an airport with an RVR of 600′ would be written as “600.”

• The information block also possesses the tower frequency. The tower frequency is the frequency that is used to communicate with the control tower. It is given in MHz and is typically 118.0 or 119.0. For example, an airport with a tower frequency of 118.0 would be written as “118.”

• Another factor to remember is that the NDB identifier is the code used to identify the NDB. It is given in five-letter groups. For example, an airport with an NDB identifier of “ABCDE” would be written as “ABCDE.”

• The Common Traffic Advisory Frequency, or the CTAF, is the frequency that is used to communicate with other aircraft in the area. It is given in MHz and is typically 121.0 or 122.0. For example, an airport with a CTAF of 121.0 would be written as “121.” For drone pilots, the CTAF is a very important frequency to remember as it is used to announce your location and intentions to other aircraft in the area.

• The Automatic Terminal Information Service or ATIS is the automated system that provides information about the airport. It is given in MHz and is typically 124.0 or 125.0. For example, an airport with an ATIS of 124.0 would be written as “124.”

• ASOS frequency is another component that is given in the information block. ASOS is an automated system that provides weather information. It is given in MHz and is typically 126.0 or 127.0. For example, an airport with an ASOS frequency of 126.0 would be written as “126.”

• The final item in the information block is the Unicom frequency. The Unicom frequency is the frequency that is used to communicate with the UNICOM operator. It is given in MHz and is typically 122.0 or 123.0. For example, an airport with a Unicom frequency of 122.0 would be written as “122.”

Now that we have covered the basics of reading an airport information block let’s move on to understanding the different airspace types depicted on a sectional chart.

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Obstacles and Terrain

• One component that the sectional chart also depicts is the height of the terrain and obstacles around the airport. This is important for all pilots to be aware of, but it is especially important for drone pilots as they are not permitted to fly above 400′ AGL without special permission from the FAA. The height of terrain and obstacles is depicted in feet above mean sea level (MSL) and is represented by brown contour lines.

• The Maximum Elevation Figure (MEF) is the highest elevation within a quadrangle. It is given feet above MSL and is represented by a brown number inside a brown triangle. For example, an airport with a MEF of 1000′ would be written as “1000.”

• There are several types of obstacles, out of which we will cover man-made obstacles less than 1000′ AGL (Above Ground Level) and those that exceed or are equal to 1000′ AGL. These are represented in the map as described below.

• A man-made obstacle is an object that has been constructed by humans, such as a building, antenna, or tower. Man-made obstacles less than 1000′ AGL are represented by a black dot with the elevation of the obstacle in feet above MSL written next to it. For example, an obstacle that is 500′ tall and has an elevation of 500′ MSL would be written as “500.”

• Man-made obstacles equal to or exceeding 1000′ AGL are represented by a black dot with the word “Tower” written next to it. The elevation of the obstacle is not given, as these are typically very tall structures.

• The sectional chart also depicts natural obstacles such as mountains, hills, and trees. These are represented by a brown dot with the elevation of the obstacle feet above MSL written next to it. For example, an obstacle that is 500′ tall and has an elevation of 500′ MSL would be written as “500.”

• Group obstacles are another category that is a combination of both man-made and natural obstacles. These are represented by a black dot with the word “Group” written next to it. The elevation of the obstacle is not given as these can vary greatly.

• Checkpoints are items on the map that can be used for navigation. They are represented by a black dot with the initial of the checkpoint and the magnetic bearing to the checkpoint from the airport written next to it. For example, a checkpoint that is located on a heading 180 degrees from the airport would be written as “C180.”

• Lines of Position (LOPs) are another type of checkpoint that can be used for navigation. They are represented by a black dot with the initial of the LOP and the magnetic bearing to the LOP from the airport written next to it. For example, a LOP that is located on a heading 180 degrees from the airport would be written as “L180.”

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The Sectional Chart Legend

The Sectional Chart Legend is located in the bottom right-hand corner of the chart and contains all of the information needed to interpret the symbols and colors used on the map. The legend is used to identify the different types of airspace, obstacles, and other items that are depicted on the chart.

Now that we have discussed the various items available on the map let us move to airspaces, what they are and what they are its types.

What is Airspace?

An airspace is a three-dimensional unit of airspace with defined dimensions within which certain rules apply. Airspaces are classified according to the type of activities that normally take place in them and the level of safety required.

The United States National Airspace System (NAS) is divided into six different types of airspace: controlled, uncontrolled, special use, restricted, prohibited, and military operation areas (MOAs).

Controlled Airspace

Controlled airspace is airspace in which air traffic control (ATC) services are provided to aircraft operating under Instrument Flight Rules (IFR). This type of airspace typically has the highest activity level and the strictest rules.

Uncontrolled Airspace

Uncontrolled airspace is where ATC services are not provided, and aircraft are not required to operate under IFR. This type of airspace typically has a lower level of activity and less strict rules.

Special Use Airspace

Special use airspace has been designated for a specific purpose, such as military training or air traffic control. This type of airspace typically has restricted access and special rules that apply.

Restricted Airspace

Restricted airspace is airspace in which entry is prohibited or severely limited due to a hazardous condition. This type of airspace is typically marked on a Sectional Chart with the letter “R” followed by a number.

Prohibited Airspace

Prohibited airspace is airspace in which entry is completely prohibited. This type of airspace is typically marked on a Sectional Chart with the letter “P” followed by a number.

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Military Operation Areas (MOAs)

MOAs are areas of airspace that have been designated for military training activities. This type of airspace typically has special rules that apply and is often active only during certain times of the day.

Other areas to take note of are warning areas, alert areas, and military training routes. A warning area is an airspace that may contain hazardous conditions such as airshows, parachute jumping, and rocket launches. An alert area is an airspace with a high aircraft activity level. Military training routes are areas of airspace that are used by the military for training purposes. These routes are often active only during certain times of the day and have special rules that apply.

In the sectional chart, the depiction of a warning area, alert area, or military training route is similar to that of restricted airspace. The difference is that warning areas, alert areas, and military training routes are not airspaces in which entry is prohibited.

Rather, they are areas where pilots should exercise caution due to the increased level of activity. Warning areas are marked as W-XXX, alert areas are marked as A-XXX, and military training routes are marked as T-XXX.

Now that we have discussed the different types of airspace, let us move on to how they are depicted on a Sectional Chart.

Airspace Depictions on Sectional Charts

Controlled Airspace

Controlled airspace is typically depicted on Sectional Charts as either Class A, B, C, D, or E airspace.

Class A Airspace

Class A airspace is depicted on Sectional Charts as a solid magenta line. This type of airspace typically surrounds major metropolitan areas and is located at altitudes above 18,000 feet MSL up to 60,000 MSL.

Class B Airspace

Class B airspace is depicted on Sectional Charts as a solid blue line. This is the most controlled airspace in the National Airspace System (NAS). You must have Air Traffic Control (ATC) clearance to enter Class B airspace.

This is generally not available to drone pilots. This applies to the altitudes that start from the surface and reach up to 9000 feet. This refers to controlled airspace around the busiest airports in the country.

Class C Airspace

Class C airspace is depicted on Sectional Charts as a dashed magenta line. This type of airspace is generally located around larger airports and extends from the surface up to 4000 feet AGL. You must have a clearance from ATC to enter Class C airspace.

Class D Airspace

Class D airspace is depicted on Sectional Charts as a dashed blue line. This type of airspace is generally located around smaller airports and extends from the surface up to 2000 feet AGL. You must have a clearance from ATC to enter Class D airspace.

Class E Airspace

Class E airspace is not shown on Sectional Charts. This type of airspace is generally located around smaller airports and extends from the surface up to 14,500 feet MSL. You do not need clearance from ATC to enter Class E airspace, but you must maintain radio communication with ATC while operating in this area.

Class G Airspace

Class G airspace is not shown on Sectional Charts. This is uncontrolled airspace and is generally located away from airports. Class G airspace extends from the surface up to 1400 feet AGL. You do not need clearance from ATC to enter Class G airspace, but you must maintain radio communication with ATC while operating in this area.

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Temporary Flight Restrictions

TFRs, as they are commonly pronounced, are used to refer to areas of airspace that have restrictions placed on them for a specific period of time. TFRs are generally put in place for events such as VIP movements, natural disasters, and large sporting events.

A TFR is depicted on Sectional Charts as a shaded magenta area with the start and end time of the restriction noted inside. It is important to note that TFRs can pop up at any time, and the pilot must be aware of them.

It is important for drone pilots to always check for TFRs before flying, as they can change at any time, and you could inadvertently violate airspace.

Why should you learn to read a sectional chart?

Now that we have discussed the different types of airspace and how they are depicted on Sectional Charts, let us move on to the benefits of reading a Sectional Chart.

• Sectional charts provide vital information for pilots
• Sectional charts are used to depict the airspace
• Sectional charts show different types of airspace
• Sectional charts can be used to find TFRs
• Sectional charts are a valuable tool for pilots.

Sectional charts provide vital information for pilots and are a valuable tool for planning flights. Sectional charts show different types of airspace, which can be helpful for avoiding controlled airspace.

Sectional charts also depict temporary flight restrictions, which can be important for avoiding violation of airspace. In summary, learning to read a sectional chart is an important skill for all pilots.

Conclusion

This blog began with a brief description of Sectional Charts and their utility to pilots. We then delved into the depths of Sectional Charts by discussing the different types of airspace that are shown on them.

Finally, we ended with a discussion on the benefits of reading Sectional Charts. Sectional charts are an important tool for all pilots, and we hope this blog has helped you understand them better. Thanks for reading!