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Airspace and charts
How to read an airport entry in the Chart Supplement
The Chart Supplement is the FAA directory with the most detail on each public airport, revised every 56 days. For a drone pilot the key lines are elevation, communications (CTAF and tower hours), remarks, and the airspace line that says what class applies and what it becomes when the tower closes.
What is the Chart Supplement and who uses it?
The study guide describes the Chart Supplement U.S., formerly the Airport/Facility Directory, as the source with the most comprehensive information on a given airport. It covers airports, heliports and seaplane bases open to the public, is published in regional volumes, and is revised every 56 days. It is also available digitally from the FAA, which lists a current cycle and a next cycle for each region. For the South Central volume, the cover reads 29 Oct 2026 to 24 Dec 2026, the same cycle as the sectionals.
A sectional chart shows a summary data block for each airport. The Chart Supplement is where the chart sends you for anything the block cannot hold. The chart's own legend points to it for lighting limitations, part-time tower hours, and operating restrictions.
Sources (checked 2026-11-14): FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22); FAA Chart Supplement page; FAA Aeronautical Chart Users' Guide (effective 9 July 2026).
What does an airport entry look like?
Entries follow a fixed order, explained in the legend at the front of each volume. Here is a made-up entry in that style for an imaginary airport. The numbers are invented for the example.
SAMPLE FIELD (KSMP) 2 E UTC-6(-5DT) N35 00.00 W93 00.00
430 B NOTAM FILE SMP
RWY 03-21: H5000X100 (ASPH) MIRL
AIRPORT REMARKS: Attended Mon-Fri 1400-2300Z. Deer on and invof arpt.
Parachute Jumping.
WEATHER DATA SOURCES: ASOS 119.575
COMMUNICATIONS: CTAF 128.0 ATIS 119.575 UNICOM 122.95
TOWER 128.0 (1200-0400Z) GND CON 121.8
AIRSPACE: CLASS D svc 1200-0400Z; other times CLASS E.Reading it line by line, using the legend's definitions:
| Part of the entry | What it tells you |
|---|---|
| Name, identifier and location | The "2 E" is the airport location: distance and direction from the center of the associated city, in nautical miles. "UTC-6(-5DT)" tells you how many hours to subtract from UTC for local standard time and daylight time. |
| Elevation (the 430) | The highest point of the airport's usable runways, in feet MSL. It is the number you use for airspace and altitude conversions near the field. |
| Runway data | Runway number, surface, length by width in feet, and lighting. It also lists runway-end details, such as obstacles. |
| Airport remarks | Attendance schedule and hazards or activities the sectional cannot show. The legend says remarks are limited to information essential to safe operation and in effect for more than a few days. |
| Weather data sources | Which automated systems report (ASOS, AWOS and similar) and their frequency or phone number. |
| Communications | CTAF, UNICOM and ATIS frequencies, then the tower and ground frequencies with hours in UTC. |
| Airspace | The class of airspace, when it is in service, and what it becomes at other times. |
Sources (checked 2026-11-14): FAA Chart Supplement page; FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22).
How do I read the elevation, and why does it matter?
The legend defines elevation as the highest point of an airport's usable runways, measured in feet from mean sea level. When the elevation is below sea level, a minus sign precedes it. For a drone, the elevation turns MSL airspace numbers into AGL numbers, the way a spot elevation on a chart does.
Worked example
Class D ceiling from the entry
Say the entry above shows an elevation of 430 ft MSL and a Class D tower. Class D is generally the surface to 2,500 ft above the airport elevation, so the ceiling is near 2,930 ft MSL, which the chart would show as about 29. Your drone at 300 ft AGL near the field is at roughly 730 ft MSL, well inside that column, so authorization applies while the tower is open.
Compare the Class D guide for the part-time hours problem and see Class D airspace for drones.
What do the tower hours and the airspace line mean?
Hours in the Chart Supplement are in UTC and shown with a Z. The legend's time conversion item says to subtract the listed number of hours from UTC to get local standard time and local daylight time. It also uses a dagger-style mark after hours (shown as ‡ in entries) and explains that during daylight saving time the effective hours are one hour earlier in UTC than shown.
Worked example
Converting tower hours
In the sample, the tower runs 1200-0400Z and local time is UTC-6 in standard time. 1200Z minus 6 hours is 6:00 a.m., and 0400Z minus 6 hours is 10:00 p.m. That is the tower's open window in standard time. During daylight time the airport is UTC-5, and the real UTC hours shift one hour earlier, so the local window stays 6:00 a.m. to 10:00 p.m.
The airspace line is the one a drone pilot should read twice. The legend gives these forms:
- "CLASS B" with a pointer to the VFR Terminal Area Chart.
- "CLASS D svc" followed by the hours, then "other times CLASS E". The core surface area becomes Class E when the tower closes.
- "CLASS D svc" followed by the hours, then "other times CLASS G". The core surface area becomes Class G up to, but not including, the overlying controlled airspace, which is normally Class E starting at 700 or 1,200 ft AGL.
The legend adds that the listed times include all associated arrival extensions, and that when a surface area reverts to Class G, the extensions revert at the same time. If it reverts to Class E, the extensions remain Class E. For a Part 107 pilot, "other times CLASS E" still means authorization inside the lateral boundary of that surface area, while "other times CLASS G" means none, as the AIM and 14 CFR 107.41 set out. Read Class E airspace for drones and Class G airspace for drones for the difference.
Sources (checked 2026-11-14): FAA Chart Supplement page; AIM 3-2: Controlled Airspace; 14 CFR 107.41 (eCFR).
Which lines help me watch for manned traffic?
The Communications line gives the CTAF, the Common Traffic Advisory Frequency, which the legend defines as a program to get all vehicles and aircraft at airports without an operating control tower on one common frequency. When CTAF and UNICOM are the same, the entry prints them together as CTAF/UNICOM. Pilots at a non-towered field announce on that frequency. Knowing the CTAF tells you which frequency to monitor on a handheld radio, if you carry one, to learn when manned aircraft are in the pattern. 14 CFR 107.37 requires the drone to yield right of way to all manned aircraft.
The traffic pattern line, where one appears, gives pattern altitude. The legend says the first figure is the pattern altitude above mean sea level, and a second figure in parentheses is above airport elevation. It is only published if it differs from the recommended altitudes in the AIM, so a missing line does not mean no pattern. The sectional also prints "right traffic" notes (for example, runway 23 at Chesapeake Regional on the free Norfolk chart, Figure 20) where a runway uses right-hand patterns.
Sources (checked 2026-11-14): FAA Chart Supplement page; 14 CFR 107.37 (eCFR).
What do airport remarks and attendance mean?
The legend defines the attendance schedule as the months, days and hours the airport is actually attended, and says attendance does not mean watchman duties or telephone access. The remarks section holds items such as parachute jumping, deer and wildlife on the field, agricultural operations at low altitude, and special air traffic rules. For a drone pilot, remarks are your clue about low or unusual manned activity near the field, before you apply for an authorization or choose a site.
When a sectional shows a parachute jump symbol (Norfolk's Figure 20 has one near area 1) the Chart Supplement is where the details are published, according to the study guide, and the remarks entry may say whether activity is regular.
Sources (checked 2026-11-14): FAA Chart Supplement page; FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22).
What are the common test traps with the Chart Supplement?
- Forgetting where the hours live. The sectional's star only says a tower is part time. The Chart Supplement gives the hours and what the airspace reverts to. Practice questions on the Figure 69 note about NOTAMs and the directory test exactly this.
- Reading Z time as local time. All hours are UTC unless stated.
- Confusing elevation and traffic pattern altitude. Elevation is the airport. The pattern line is a separate item and carries MSL first.
- Assuming the entry applies to drones. It does not issue rules for UAS. It tells you what airspace and traffic exist. Authorization still comes through LAANC or FAADroneZone.
- Using an old edition. Check the 56 day dates on the cover.
Practice airport symbol reading and frequencies in the free chart lessons.
Free practice questions on this topic
2 original questions from the Sectional Cue bank. Try each one, then open the answer.
Part-time Class D hours
1. In Figure 69, the note See NOTAMs/Directory for Class D eff hrs appears near Cabaniss NOLF (NGW). Where should a remote pilot check when that Class D is in effect? (uses Figure 69, open the free chart lesson)
- In the sectional chart legend
- In NOTAMs and the Chart Supplement
- On the nearest airport's AWOS broadcast
Show answer and explanation
B. In NOTAMs and the Chart Supplement
The note means the Class D is part time, and its effective hours are published in the Chart Supplement (formerly the Airport/Facility Directory) and changes appear by NOTAM. The chart legend explains symbols but not hours. An AWOS broadcasts weather, not airspace hours.
Source: FAA-CT-8080-2H, Figure 69; Chart Users' Guide; 14 CFR 107.41
CTAF
2. In Figure 20, a remote pilot flying near area 2 wants to listen to local traffic calls at Chesapeake Rgnl (CPK), which has no tower. Which frequency should be monitored? (uses Figure 20, open the free chart lesson)
- 123.675
- 118.9
- 123.075
Show answer and explanation
C. 123.075
The C in a circle follows 123.075, marking it as the CTAF where pilots at a nontowered airport announce their positions. 123.675 is the AWOS-3 automated weather broadcast. 118.9 is the Norfolk Approach frequency printed in the nearby contact box, which is not where local pattern traffic calls are made.
Source: FAA-CT-8080-2H, Figure 20; Chart Users' Guide; AC 107-2A
Related guides
- Class D airspace for drone pilots
- Class E airspace for drone pilots
- Latitude, longitude, scale and MEF on a sectional chart
- Free sectional chart practice
- Airport markings and signs for drone pilots
- All Part 107 guides
Study the charts on your phone
Sectional Cue has 1150+ original questions with explanations, 27 FAA figures you can tap to read, and timed 60-question rehearsals. About 152 questions and three chart lessons are free.
Sources
- FAA Chart Supplement page, checked 2026-11-14
- FAA Remote Pilot sUAS Study Guide (FAA-G-8082-22), checked 2026-11-14
- AIM 3-2: Controlled Airspace, checked 2026-11-14
- FAA Aeronautical Chart Users' Guide (effective 9 July 2026), checked 2026-11-14
- 14 CFR 107.41 (eCFR), checked 2026-11-14
- 14 CFR 107.37 (eCFR), checked 2026-11-14
How this page was made: written by Certloom Learning from the sources above, with the rules checked against the current regulation text. Practice items are original questions from the app's reviewed bank. Spot an error? certloomlearning@gmail.com.