What do the different colored lines and shading on a sectional aeronautical chart mean for UAS pilots?

On a sectional aeronautical chart, magenta and blue colors are used to depict different classes of controlled airspace — for example, magenta vignette shading indicates Class E airspace that begins at the surface, while blue and magenta dashed lines denote Class D and Class C airspace boundaries respectively. Class B airspace is shown with solid blue lines forming concentric rings, often described as an 'upside-down wedding cake' shape. UAS pilots operating under 14 CFR Part 107 must identify these boundaries because flight in Class B, C, D, and surface-level Class E airspace requires prior authorization through the FAA's LAANC system or DroneZone before operations begin.

How do you find restricted or prohibited areas on a sectional chart before a UAS flight?

Restricted and prohibited areas are depicted on sectional aeronautical charts with blue hatched boundary lines and labeled with identifiers such as 'R-' for restricted areas and 'P-' for prohibited areas, followed by a number (for example, P-40 over Camp David). Pilots can reference the chart's accompanying legend and the FAA's Chart Supplement to find the altitude limits and controlling agency for each special use airspace area. Under 14 CFR Part 107, UAS pilots must avoid prohibited areas entirely and may only operate in restricted areas when authorized by the controlling agency.

What is the difference between Class D and Class E airspace as shown on a sectional chart, and why does it matter for drone pilots?

Class D airspace is depicted by a blue dashed line and typically surrounds airports with an operational control tower, extending generally from the surface up to 2,500 feet AGL. Class E airspace, shown with either a magenta dashed line (surface area) or a magenta vignette (beginning at 700 feet AGL), is controlled airspace that serves as a transition area between controlled and uncontrolled airspace. The distinction matters for Part 107 remote pilots because both require airspace authorization before flight, but the authorization ceilings, controlling facilities, and LAANC grid availability can differ significantly between the two classes.

Sectional Chart Reading for UAS Pilots

Before a drone leaves the ground, a Remote Pilot in Command (RPIC) must know exactly what airspace sits above the launch point. The sectional aeronautical chart — the same large-format chart that student pilots use to plan cross-country flights — is the foundational document for making that determination. For Part 107 operators, chart reading is not an optional skill reserved for aviation enthusiasts; it is a regulatory necessity. Flying in certain airspace without authorization is a direct violation of 14 CFR Part 107, and the FAA knowledge test will probe your ability to decode sectional symbols with precision.

This article walks through the most important sectional chart elements for UAS pilots: airspace classes and their boundaries, special-use airspace depictions, surface features, and the practical workflow for applying chart information to a pre-flight planning session. While drone pilots do not fly cross-country routes like manned aircraft, they must interpret the same two-dimensional airspace architecture depicted on every sectional chart published by the FAA's Aeronautical Information Services.

Understanding the Sectional Chart

A sectional aeronautical chart is a 1:500,000-scale topographic and aeronautical map. One inch on the chart equals approximately 6.86 statute miles on the ground, which is about 5.96 nautical miles. Charts are updated on a 56-day (eight-week) revision cycle to reflect changes in airspace, obstacles, and navigation aids. UAS pilots should always use a current chart — or, more commonly in modern practice, a current digital equivalent such as the FAA's SkyVector website or the B4UFLY app, both of which draw from the same official aeronautical data. However, the FAA knowledge test requires you to read a printed sectional, so mastering the paper chart symbols is essential.

The chart legend, printed on the folded chart itself, defines every symbol used. Treat the legend as a required reference during both study and actual pre-flight planning. The most critical elements for Part 107 purposes fall into three categories: airspace classification boundaries, special-use airspace (SUA), and airport depictions.

Airspace Classes and Their Chart Depictions

Class B Airspace

Class B airspace surrounds the nation's busiest airports. On a sectional chart, it appears as solid blue lines forming concentric rings or irregular shapes, resembling an upside-down wedding cake when viewed in three dimensions. Each ring is labeled with its altitude limits: the upper altitude is shown above a horizontal line, and the lower altitude (or the floor) is shown below it, both expressed in hundreds of feet MSL. For example, a label reading 100/30 means the floor of that segment is 3,000 feet MSL and the ceiling is 10,000 feet MSL. UAS pilots need authorization via the Low Altitude Authorization and Notification Capability (LAANC) or an FAA Drone Zone waiver to operate within Class B airspace.

Class C Airspace

Class C airspace surrounds airports with an operational control tower and radar approach control. It is depicted with solid magenta lines, also in concentric rings, typically with an inner circle of 5 nautical miles radius and an outer shelf extending to 10 nautical miles. Altitude limits are labeled the same way as Class B — upper altitude over lower altitude. The surface area of Class C (the inner ring) typically extends from the surface to 4,000 feet AGL. LAANC authorization or a waiver is required for UAS operations within Class C.

Class D Airspace

Class D airspace surrounds airports with an operational control tower but without radar approach control. It is shown as a dashed blue circle on the sectional chart. The lateral boundary is typically a 4–5 nautical mile radius from the airport center. The altitude ceiling is depicted in a dashed blue box adjacent to the airspace symbol, expressed in hundreds of feet MSL — for example, [26] means the Class D ceiling is 2,600 feet MSL. The floor is the surface. LAANC authorization is required for Part 107 operations in Class D.

Class E Airspace

Class E is the most complex and widespread controlled airspace class, and it has multiple forms on a sectional chart. The key variants are:

Class E surface areas — depicted as a dashed magenta circle around an airport. This is controlled airspace that begins at the surface and is typically designated to support instrument approaches at airports without a control tower. Part 107 pilots require LAANC authorization to fly within a Class E surface area.
Class E with a 700-foot AGL floor — shown as a faded (soft) magenta shading around airports. The shaded side of the boundary represents where the floor drops to 700 feet AGL; outside the shading, Class E begins at 1,200 feet AGL.
Class E with a 1,200-foot AGL floor — depicted as a faded (soft) blue tint over certain areas, typically federal airways. This is essentially the background airspace across most of the country.

Because most UAS operations occur below 400 feet AGL, the key regulatory question is whether the flight is within a Class E surface area (dashed magenta ring) or within the 700-foot floor zone (faded magenta shading). Neither of these automatically requires LAANC authorization under all circumstances — the FAA's LAANC grid tiles will indicate where authorization is needed and at what altitude.

Class G Airspace

Class G is uncontrolled airspace and is not explicitly depicted on a sectional chart — it exists wherever no other airspace class is defined, typically from the surface up to 700 feet or 1,200 feet AGL (depending on proximity to airports). No authorization is required for Part 107 operations in Class G, provided all other Part 107 rules are followed. On a sectional chart, you infer Class G by the absence of controlled airspace markings.

Special-Use Airspace

Special-use airspace (SUA) restricts or regulates flight activity for military, national security, or safety reasons. Sectional charts depict several types:

Prohibited Areas — shown with a blue hash-marked boundary and labeled with a P followed by a number (e.g., P-40). Flight of any aircraft, including UAS, is not permitted without specific authorization. P-40 covers Camp David; P-56 covers the airspace over Washington, D.C.
Restricted Areas — depicted with a blue hash-marked boundary and labeled with an R followed by a number (e.g., R-2508). Flight requires permission from the controlling agency. Restricted areas often contain hazardous activities such as artillery fire or missile testing.
Warning Areas — labeled with a W and extending over international waters. They contain the same hazardous activities as restricted areas, but the FAA cannot legally restrict flight there; pilots are warned instead.
Military Operations Areas (MOAs) — depicted with magenta hatching and named boundaries. MOAs segregate military training activity. Nonparticipating civilian aircraft, including UAS, may legally fly through an active MOA but assume responsibility for seeing and avoiding military traffic.
Alert Areas — labeled with an A designation and depicted with magenta hatching. They contain a high volume of pilot training or unusual aerial activity. No clearance is required, but extreme caution is advised.

Airport Depictions

Airports are shown with symbols that immediately convey whether a control tower is present. A blue airport symbol indicates a towered airport (with associated Class B, C, or D airspace). A magenta airport symbol indicates a non-towered airport. The airport name, elevation in feet MSL, and traffic pattern altitude or other notes typically appear adjacent to the symbol. The presence of a blue airport symbol is a strong visual cue that controlled airspace exists at the surface — a fact with direct Part 107 implications.

Key Numbers and Rules

Sectional charts are updated every 56 days (eight weeks) — always confirm currency before flight planning.
Class B airspace is depicted with solid blue lines; Class C with solid magenta lines; Class D with dashed blue lines.
Class E surface areas use a dashed magenta circle — the most commonly missed symbol among Part 107 test-takers.
Class E with a 700-foot floor is the faded magenta shading; Class E with a 1,200-foot floor is the faded blue tint.
Prohibited areas begin with the letter P; Restricted areas begin with R; Warning areas with W; MOAs are named (not lettered); Alert areas begin with A.
UAS operations in Class B, C, D, and Class E surface areas require FAA authorization before flight (LAANC or DroneZone waiver).
Class G is uncontrolled and unshaded — inferred by the absence of other airspace markings.

Common Test Traps

Confusing dashed magenta with dashed blue. Dashed magenta = Class E surface area (controlled, requires authorization). Dashed blue = Class D (also controlled, requires authorization). Both look like circles, but color is everything.
Assuming non-towered airports have no controlled airspace. Many non-towered airports (magenta symbol) still have Class E surface areas (dashed magenta ring) — you still need authorization to fly there under Part 107.
Misreading altitude labels on Class B and C segments. The number above the line is the ceiling; the number below (or the word SFC) is the floor. Transposing these leads to dangerous assumptions about where airspace begins.
Treating MOAs as prohibited. MOAs are not prohibited or restricted areas — you may fly through them without prior permission, though caution and awareness of military activity are essential.
Using an outdated chart. The FAA knowledge test uses current sectional excerpts. Train and practice with charts dated within the last 56 days, and verify that the specific chart edition matches any practice problems you are using.