How to Read a Sectional Chart: A Drone Pilot's Guide

Updated August 2026 · Part 107 Quiz editorial team

On exam day you will be handed a booklet of chart excerpts — the FAA's Airman Knowledge Testing Supplement — and asked questions that can only be answered by reading them. This is the single most reliable place to lose points, because chart questions do not reward familiarity with the regulations. They reward knowing what a fuzzy magenta band means and being able to subtract one number from another under time pressure.

The good news is that the sectional is a closed system. There are maybe fifteen symbols a remote pilot ever needs, and once you can name them the questions become arithmetic. This guide covers those fifteen.

What a Sectional Chart Is

A VFR Sectional Aeronautical Chart is the FAA's 1:500,000-scale visual navigation chart — roughly one inch to seven nautical miles. Each chart covers a named region (Seattle, Dallas–Ft Worth, New York), and the FAA publishes them on a 56-day cycle. Every chart carries an effective date on its cover panel, and an expired chart is a genuine hazard: airspace boundaries, tower heights, and frequencies all change between editions.

You are not expected to buy paper charts. SkyVector, VFRMap, and the FAA's own digital products display the same charts free, and B4UFLY and the LAANC supplier apps overlay the airspace data on top of a map. But the exam tests the chart itself, in black-and-white-and-magenta, so learn it in that form.

Airspace: The Color Code

This is the highest-value table on the page. Learn it cold, because it decides whether a flight needs FAA authorization at all.

Two rules cover almost every case. Solid or dashed lines mean the airspace reaches the ground, so a drone flight inside them needs authorization no matter how low it stays. Fuzzy vignettes mean the airspace starts overhead — 700 ft AGL for magenta, 1,200 ft for blue — so a flight capped at 400 ft AGL underneath is in Class G and needs nothing.

The dashed magenta line versus the fuzzy magenta band is the distinction the exam returns to again and again, and the two look similar at a glance on a small excerpt. Dashed line, sharp edge, authorization required. Fuzzy band, soft edge, you are underneath it. Our airspace classes guide goes deeper on what each class is for, and the LAANC guide covers how the authorization itself gets granted.

Reading the numbers inside Class B and C

Class B and Class C segments carry a pair of numbers stacked like a fraction — for example 100 over 40. Those are hundreds of feet MSL: the shelf runs from 4,000 ft MSL up to 10,000 ft MSL. A floor written as SFC means the segment reaches the surface. Class D airspace instead shows a single bracketed number such as [25], which is the ceiling in hundreds of feet MSL — 2,500 ft MSL, with the floor at the surface.

Airport Symbols and Data Blocks

Airport color tells you one thing immediately: blue means the field has a control tower, magenta means it does not. Airports with a hard-surfaced runway of 8,069 ft or longer are drawn as a scaled runway outline; smaller fields appear as circles with runway lines. Tick marks around the circle indicate fuel is available during normal business hours, and a star above the symbol means a rotating beacon operates from sunset to sunrise.

Underneath the symbol sits the data block. A typical non-towered entry reads something like:

HARTSVILLE (HTV) ⊕ 412 L 42 122.7

• 412 — field elevation in feet MSL. This is the number you use to convert chart MSL altitudes into your AGL limits.
• L — runway lighting is available, at least part of the night.
• 42 — length of the longest runway in hundreds of feet: 4,200 ft.
• 122.7 — the frequency. A circled Ⓒ beside it marks the CTAF, the common traffic advisory frequency pilots self-announce on at a non-towered field. At a towered field you will instead see CT followed by the tower frequency, and often an ATIS frequency below it.

For a remote pilot the CTAF matters more than it looks. Monitoring it near an uncontrolled field is how you hear the Cessna announcing a left downwind before you see it — and yielding right of way to manned aircraft is not optional under 107.37.

Terrain, Obstructions, and the MSL Trap

Each half-degree quadrangle on the chart carries a large bold blue number called the Maximum Elevation Figure (MEF). It is written in thousands and hundreds of feet MSL, so an MEF shown as a large 2 and a smaller 1 means 2,100 ft MSL. The MEF is the highest known terrain or obstacle anywhere in that quadrangle, rounded up — a quick clearance check, not a precise obstacle height.

Individual obstructions get their own symbols, and they come with two numbers:

• Bold number, no parentheses — the top of the obstruction in feet MSL.
• Number in parentheses — the height of the obstruction above the ground, in feet AGL.
• Lightning-bolt rays around the symbol mean the obstruction is lighted.
• A taller, doubled symbol marks obstructions 1,000 ft AGL or higher.

So a tower printed as 1179 (285) stands 285 ft above the ground, and its top is 1,179 ft above sea level — which also tells you the ground beneath it sits at roughly 894 ft MSL.

Remember the one structure exception in 107.51(b): within a 400-ft radius of a structure, you may climb to 400 ft above that structure's uppermost limit. A 285-ft tower therefore supports a legal 685 ft AGL inspection flight — but only while you stay inside that radius.

Special Use Airspace

Hatched bands mark airspace with restrictions attached. The name inside tells you which kind, and the chart margin carries a panel listing each area's altitudes, operating times, and controlling agency.

National security UAS flight restrictions and TFRs are a separate matter. They are not printed on the sectional at all, because they change daily — check NOTAMs or B4UFLY before every flight, even after LAANC has approved you.

A Worked Example

Say a chart excerpt shows your job site inside a dashed magenta circle around a magenta airport symbol whose data block reads 318 L 35 123.0 Ⓒ, with a tower half a mile east printed as 703 (385).

1. Airspace. Dashed magenta means Class E to the surface, so this flight needs FAA authorization before takeoff. The magenta airport symbol means there is no control tower — the authorization still comes from the FAA, not from anyone at the field.
2. Ceiling. Field elevation 318 ft MSL, so a 400 ft AGL flight tops out near 718 ft MSL.
3. The tower. It rises 385 ft AGL, above your 400-ft working ceiling in practical terms, and its top at 703 ft MSL sits just below your ceiling in MSL. Stay well clear laterally, or use the 107.51(b) structure exception deliberately and stay inside the 400-ft radius.
4. Radio. 123.0 is the CTAF. Monitoring it costs nothing and tells you when someone is entering the pattern.

Four steps, no memorized regulation beyond the airspace table. That is what chart questions actually are.

What the Exam Expects

You will not be asked to plot a course or to use a plotter. Remote pilot chart questions cluster tightly around: identifying the airspace class at a marked point, deciding whether authorization is required there, reading a field elevation or a runway length out of a data block, converting between MSL and AGL, identifying the CTAF, and interpreting an obstruction's two heights. The legend is printed in the supplement you are given, so the skill being tested is speed and confidence, not recall.

Test Yourself

Airspace and chart reading together account for the largest share of failed sections. Drill them with our Airspace practice questions, which include chart-symbology and facility-map items, then run a full Part 107 mock exam to see how they mix with weather and operations. Other knowledge areas are in the Study Guide.

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