Reading Sectional Charts

Private Pilot License (PPL) Notes

This section covers the basics of reading sectional charts, including understanding latitude and longitude, chart symbols, and how to locate positions and measure distances on the chart.

Understanding Latitude and Longitude:

1. The Equator divides the world into the Northern and Southern Hemispheres.
   1. From the Equator to the North Pole is 90 degrees.
   2. Parallels or lines of latitude run parallel to the Equator.
   3. The contiguous 48 United States lie between 25° and 49° North latitude.
2. Lines of Longitude (Meridians):
   1. Run from the North Pole to the South Pole at right angles to the Equator.
   2. The Prime Meridian (0° longitude) passes through Greenwich, England.
   3. The contiguous 48 United States lie between 67° and 125° West longitude.
3. Locating Positions:
   1. A specific position is given by its latitude and longitude (e.g., 39°N latitude and 77°W longitude locates Washington D.C.).
   2. Latitude is always given first, followed by longitude.

Using Sectional Charts:

1. Latitude and Longitude on Charts:
   1. Degree lines are shown and subdivided by tick marks (each tick mark equals 1 minute).
   2. There are 60 minutes in each degree.
2. Finding a Location (Example: Clermont County Airport):
   1. Coordinates are given as 39° 5' N latitude and 84° 13' W longitude.
   2. Count tick marks north from the latitude line and west from the longitude line to find the position.
3. Measuring Distances:
   1. Distance between lines of latitude can be measured using tick marks on lines of longitude.
   2. Each minute of latitude equals one nautical mile.
   3. Distances can be verified using the nautical scale on the chart.

Interpreting Airport Symbols:

1. Airport Symbol Basics:
   1. Hard-surfaced runways greater than 8,069 feet have specific symbols.
   2. Runways between 1,500 and 8,069 feet are indicated differently.
   3. Seaplane bases and airports with non-hard-surfaced runways have unique symbols.
2. Additional Airport Information:
   1. An "R" indicates a private airport with emergency or landmark value.
   2. Airports with control towers are shown in blue; others are in magenta.
3. Example: Clermont County Airport:
   1. Magenta circle indicates a hard-surfaced runway without a control tower.
   2. Tick marks around the circle indicate fuel availability and attendance during normal hours.
   3. Runway length, elevation, lighting, and communication frequencies are provided alongside the airport name.
4. Example: Cincinnati Lunken Airport:
   1. Blue symbols indicate a tower-controlled airport.
   2. Information includes runway length, elevation, tower frequencies, and beacon operation.

Terrain and Obstructions:

1. Contour Lines:
   1. Connect points of equal elevation above mean sea level.
   2. Basic contours are spaced at 500-foot intervals.
   3. Spacing indicates slope steepness; widely spaced for gentle slopes, closely spaced for steep slopes.
2. Color Tints:
3. Show elevation bands, from light green (lower elevations) to brown (higher elevations).
4. Obstruction Symbols:
   1. Man-made features over 200 feet above ground level are shown (e.g., antennas, smokestacks).
   2. Different symbols indicate obstructions below and above 1,000 feet AGL.
   3. Details include elevation above sea level and height above ground level.
   4. Symbols also indicate groups of obstacles, under-construction obstacles, obstacles with lighting, and wind turbines.
5. Maximum Elevation Figures (MEF):
   1. Shown in quadrangles bounded by ticked lines of longitude and latitude.
   2. Represented in thousands and hundreds of feet above mean sea level.
   3. Calculated slightly higher than the highest known feature in the quadrangle.

Navigating Using Sectional Charts:

1. Sample Route: Clermont County Airport to Fayette County Airport to Richmond Airport and back:
   1. Identify landmarks such as highways, towns, racetracks, power lines, railroads, and airports along the route.
   2. Note obstruction symbols and use them to ensure safe altitudes during flight.
   3. Use visual checkpoints (e.g., magenta flags) to report positions to ATC if necessary.
   4. Pay attention to MEFs to maintain terrain clearance.
2. Understanding Special Symbols:
   1. Magenta flags denote visual checkpoints for ATC communication.
   2. Parachute activity symbols indicate areas where parachuting occurs.
   3. Private or restricted airports are marked for emergency or landmark purposes.
3. Measuring Distances Along the Route:
   1. Use tick marks on lines of longitude to measure distances between points.
   2. Confirm distances using the nautical scale provided on the chart.

By understanding how to read sectional charts, including the symbols and scales used, a new pilot can effectively navigate and ensure safe flying practices.