Sky107
Chapter UAG.III

Airspace Classification and Operating Requirements

FAA Part 107 study guide with diagrams — part of the Sky107 UAG knowledge test preparation course.

Airspace Classification and Operating Requirements

Chapter Overview

This chapter covers the airspace environment in which remote pilots operate and the regulatory limitations that govern small unmanned aircraft systems (sUAS) under 14 CFR Part 107. Successful mastery of this material requires understanding the structure and classification of the National Airspace System (NAS), the requirement to obtain air traffic control authorization when operating in controlled airspace, the operating limitations imposed by Part 107, including altitude, speed, weather, and right-of-way rules, and the special procedures required for operations near structures, at night, and around temporary flight restrictions. Remote pilots must be able to interpret aeronautical charts to identify the classification of airspace at a planned operating location, determine whether authorization is required, and recognize the boundaries and active times of that airspace. This chapter integrates the visual chart-reading skills of a pilot with the procedural knowledge of Part 107 operating rules, emphasizing both safety and regulatory compliance.

Airspace Classification and Chart Depiction

Airspace Profile: Classes A, B, C, D, E and G — FAA Part 107 Airspace Profile — The Layer Cake FAA Part 107 Small UAS · UAG ACS FAA-S-ACS-10 · FAA-G-8082-17B Class A Class B Class C Class D Class E Class G FL 600 (60,000 ft MSL) 18,000 ft MSL 10,000 ft MSL 4,000 ft AGL 1,200 ft AGL Surface (0 ft) CLASS A 18,000 ft MSL to FL 600 IFR only — all flights ATC controlled CLASS B Surface to 10,000 ft MSL "Upside-down wedding cake" ATC clearance required CLASS C Surface to 4,000 ft AGL Shelf + outer ring Two-way radio comm required CLASS D Surface to 2,500 ft AGL Around control towers Two-way radio comm required CLASS E — Controlled airspace not otherwise classified Starts 1,200 ft AGL (or 700 ft AGL near airports) CLASS G — Uncontrolled Surface to 1,200 ft AGL (typical) No ATC clearance or radio comm required 400 ft AGL — Part 107 limit FL 600 ceiling 10,000 ft MSL 4,000 ft AGL 1,200 ft AGL Part 107 Key Point: Small UAS operations are generally limited to Class G airspace at or below 400 ft AGL without ATC authorization. Operations in Class B, C, D, or E require prior ATC authorization.

The National Airspace System is divided into classes of airspace, each with distinct operating requirements and chart depictions. A remote pilot must be able to identify the type of airspace at the intended flight location before beginning operations.

Class B Airspace

Class B airspace surrounds the nation's busiest airports and is designed to contain all published instrument procedures. It is depicted on sectional charts with solid blue lines. The airspace typically resembles an upside-down wedding cake, with multiple shelves extending outward and upward from the surface area around the primary airport. Operations within Class B airspace are strictly regulated for all aircraft, and small UAS operations require prior ATC authorization.

Class C Airspace

Class C airspace surrounds airports with a moderate level of commercial air carrier and instrument traffic. It is depicted on sectional charts with dashed blue lines. Class C airspace generally consists of a surface area of a 5-nautical-mile radius and a shelf area extending to a 10-nautical-mile radius at altitudes from 1,200 to 4,000 feet above the airport elevation. A remote pilot must obtain ATC authorization before operating a small UAS within the lateral boundaries of Class C airspace, regardless of planned altitude.

Class D Airspace

Class D airspace surrounds airports with an operational control tower but is generally smaller and less complex than Class B or C airspace. It is depicted on sectional charts with dashed magenta lines. Class D airspace typically extends from the surface to a designated altitude, often 2,500 feet above the airport surface. On some charts, a segmented dashed magenta or blue circle indicates Class D airspace when the airspace does not extend to the surface, but the underlying concept remains the same: authorization is required for Part 107 operations within the lateral boundaries of Class D airspace during the tower's operational hours.

Class E Airspace

Class E airspace is controlled airspace that is not Class A, B, C, or D. It can begin at the surface, at 700 feet AGL, or at 1,200 feet AGL, depending on the location and chart depiction. Solid magenta lines depict Class E surface areas designated for an airport, while dashed magenta lines typically indicate Class E airspace beginning at 700 feet AGL. A remote pilot must obtain ATC authorization only when operating within the lateral boundaries of surface-level Class E airspace designated for an airport. Class E airspace that begins at 700 or 1,200 feet AGL does not require authorization for operations below those altitudes, but operations above those altitudes require prior authorization.

Class G Airspace

Class G airspace is uncontrolled airspace, meaning there is no air traffic control separation service provided. It is the only airspace class designated as uncontrolled. Class G airspace typically extends from the surface to the base of the overlying controlled airspace, commonly Class E beginning at 700 or 1,200 feet AGL. Part 107 operations in Class G airspace do not require ATC authorization. Most rural areas without a nearby controlled airport are located within Class G airspace.

Special Use Airspace and Temporary Restrictions

Military Operations Areas (MOAs) are special use airspace established to separate military training activities from IFR traffic. MOAs are not controlled airspace as defined in 14 CFR 107.41, so no ATC authorization is required to operate a small UAS within an MOA. Remote pilots must, however, exercise extreme caution and remain clear of active military operations, yielding the right of way to military aircraft at all times.

Temporary Flight Restrictions (TFRs) are issued by the FAA through NOTAMs to protect persons, property, or activities in the air or on the ground. Common reasons for TFRs include VIP movements, natural disasters, large public events, and emergency response operations. TFRs apply to all aircraft, including small unmanned aircraft. Under 14 CFR 107.45, a remote pilot may not operate a small UAS within a restricted area, prohibited area, or TFR unless authorized by the FAA or the specific NOTAM. When a TFR is discovered during preflight planning or becomes active during flight, the remote pilot must avoid the area or land as soon as practicable. There is no exception for operating below 400 feet AGL within an active TFR.

TFR Alert: NOTAM-Issued No-Fly Zone - FAA Part 107 Airspace TFR Alert: NOTAM-Issued No-Fly Zone FAA Part 107 / ACS N TFR NO-FLY ZONE SFC–UNLTD TFR CENTER DETOUR (5 mi around) below 400 ft is fine LAND ASAP NOTAM: FDC 9/1234 - TFR SFC-UNLTD. NO UAS OPS W/I 5NM. TFR = Temporary Flight Restriction • NOTAM-issued no-fly zone • Applies to ALL aircraft • Includes drones (Part 107) Altitude Rule TFRs apply from Surface to Unlimited (SFC–UNLTD) No altitude exemption If TFR Activates Mid-Flight 1. Land as soon as practicable 2. Do not fly through TFR 3. Check NOTAMs before flight Key Exam Tip Always check NOTAMs during preflight planning. TFRs can pop up with little notice. NOTAM = Notice to Air Missions TFR Boundary Drone Path Detour ■ Land ASAP

Controlled Airspace Authorization Requirements

14 CFR 107.41 forms the backbone of airspace authorization requirements for remote pilots. It states that no person may operate a small unmanned aircraft in Class B, Class C, or Class D airspace, or within the lateral boundaries of the surface area of Class E airspace designated for an airport, unless that person has prior authorization from the FAA.

Key Authorization Principles

MSL to AGL Authorization Altitude Conversion - FAA Part 107 MSL to AGL Authorization Altitude Conversion Ground Level (MSL reference) AUTHORIZATION CEILING 500 ft MSL 400 ft MSL 100 ft AGL EXCEEDS Altitude Conversion 500 ft − 400 ft = 100 ft AGL Usable altitude above ground AGL = MSL − ground elevation Authorization ceiling − ground MSL = AGL limit ⚠ Exceeding the authorization ceiling violates 14 CFR Part 107.41
Prior authorization is mandatory before entering controlled airspace. A remote pilot cannot simply coordinate verbally with a control tower or rely on a telephone call.
The requirement applies regardless of the planned operating altitude. Flying at 200 feet AGL within Class D airspace with a ceiling of 2,500 feet MSL still requires authorization.
The two accepted methods for obtaining authorization are the Low Altitude Authorization and Notification Capability (LAANC) system and the FAA DroneZone portal.
A VFR flight plan, logbook endorsement, private pilot certificate, or phone call to the tower does not satisfy the authorization requirement.
Authorizations may specify altitude ceilings in MSL (mean sea level), which must be converted to AGL to understand the actual operating limit. If an authorization specifies a maximum altitude of 500 feet MSL and the ground elevation is 400 feet MSL, the maximum altitude above ground is only 100 feet AGL, regardless of the general 400-foot AGL Part 107 limit.
The remote pilot must adhere strictly to the terms of the authorization. Exceeding the specified MSL altitude violates 14 CFR 107.41 even if the aircraft remains below 400 feet AGL.

Class D Airspace When the Tower Is Closed

Class D Airspace When the Tower Closes Class D Airspace When the Tower Closes RUNWAY TOWER Class D (dashed magenta) Tower Open: Class D Class G Uncontrolled No authorization needed ✓ LAANC not required Class E Surface (solid magenta) Authorization still required ⚠ LAANC required Published tower hours Tower Open: Class D Tower Closed: ? Key: Tower hours determine airspace class at the surface Legend: Class D boundary Class E surface

Class D airspace is typically effective only when the control tower is operational. Remote pilots must consult the Chart Supplement U.S. to determine the published hours of operation. When the tower is closed, the airspace may revert to Class G or Class E. If the airspace reverts to uncontrolled Class G, no ATC authorization is required. If it reverts to Class E surface area, authorization remains necessary. The determining factor is the airspace classification at the actual time of operation, not the classification that exists during tower hours.

Right-of-Way Requirements

14 CFR 107.37 establishes a fundamental safety principle for all remote pilots: the small UAS must yield the right of way to all other aircraft, airborne vehicles, and launch and reentry vehicles. This requirement applies in all airspace classes, including uncontrolled Class G airspace.

Key Right-of-Way Principles

Right-of-Way Priority for Small UAS — 14 CFR 107.37 Right-of-Way Priority for Small UAS 14 CFR §107.37 — Yield to All Other Aircraft RIGHT-OF-WAY FLOW STEP 1 DETECT Scan for traffic all directions STEP 2 YIELD Give way to all aircraft STEP 3 MANEUVER Change course or altitude STEP 4 AVOID Maintain safe separation RULE — 14 CFR §107.37(a) Small UAS yields to ALL other aircraft — no privileged direction. Applies to all operations, both visual line of sight and beyond visual line of sight. UA descends to avoid Manned aircraft continues No privileged direction All aircraft treated equally Pilot responsibility Avoid collision at all costs Immediate action Maneuver promptly & safely FAA Part 107 • UAG ACS FAA-S-ACS-10 • FAA-G-8082-17B Study Guide • 14 CFR §107.37
The remote Pilot in Command (PIC) and the person manipulating the flight controls must see and avoid other aircraft and yield the right of way.
When a manned aircraft is observed approaching at the same altitude from any direction, the remote pilot must maneuver the sUAS to avoid a collision. There is no privileged direction; yielding is required regardless of whether the manned aircraft is approaching from the left, right, head-on, or on final approach.
The remote pilot must be aware of other air traffic and continuously scan for potential conflicts.
Right-of-way obligations exist even when the remote pilot is operating within controlled airspace under an active ATC authorization. ATC clearance does not relieve the remote pilot of the responsibility to see and avoid other aircraft.
When ATC issues an instruction to change course due to a potential conflict, the remote pilot must comply promptly with that instruction under 14 CFR 107.43.
In situations where compliance with an ATC instruction might endanger the aircraft or the safety of persons or property, the remote pilot may deviate but must immediately notify ATC of the deviation.

Operating Limitations Under 14 CFR Part 107

Subpart B of Part 107 establishes the operating rules that remote pilots must follow during all small UAS operations, unless a waiver is obtained.

Maximum Groundspeed

14 CFR 107.51(a) limits the groundspeed of a small UAS to no more than 87 knots (100 miles per hour). This is a hard limit. Operations conducted at 95 mph are within the regulatory limit and may continue, provided all other requirements are satisfied. The remote pilot must be aware of wind conditions, as groundspeed—not airspeed—is the controlling factor.

Minimum Visibility and Cloud Clearance

Part 107 Cloud Clearance and Visibility Minima Cloud Clearance & Visibility Minima — 14 CFR §107.51 FAA Part 107 / ACS Airspace Below Clouds Above Horizontal Visibility Class G Daytime (no ATC req.) 500 ft below clouds — (no req.) 2,000 ft horizontal 3 SM statute miles Class G Nighttime (anti-collision light) 500 ft below clouds — (no req.) 2,000 ft horizontal 3 SM statute miles Class B, C, D, E Controlled airspace 500 ft below clouds — (no req.) 2,000 ft horizontal 3 SM statute miles CLOUD 500 ft 2,000 ft Key Exam Points No "above cloud" requirement in Part 107 Night ops require anti-collision lighting visible 3 SM Visibility is always 3 SM — same day or night Memory Aid "5-2-3 Rule" 500 ft below • 2,000 ft horizontal • 3 SM visibility Applies to ALL airspace classes under Part 107 14 CFR §107.51 • FAA-G-8082-17B • UAG ACS FAA-S-ACS-10

14 CFR 107.51(c) and (d) establish minimum weather requirements:

Flight visibility must be no less than 3 statute miles. When visibility drops below this threshold during a flight—even if the aircraft remains visible—the remote pilot must terminate the operation and land as soon as practicable.
Distance from clouds must be no less than 500 feet below and 2,000 feet horizontally from any cloud. When a cloud layer is present, the remote pilot must calculate both vertical and horizontal separation. If the cloud base is at 900 feet AGL, the maximum altitude permitted is 400 feet AGL, because 900 - 500 = 400. This coincides with the standard maximum altitude but the cloud clearance is the controlling factor in that scenario.

Maximum Altitude and the Structure Exception

FAA Part 107 Maximum Altitude: 400 ft AGL and Structure Exception Maximum Altitude: 400 ft AGL & Structure Exception Open Ground Ground Level 400 ft AGL 400 ft MAX CEILING Structure Exception Ground Level 200 ft 400 ft AGL 600 ft AGL 600 ft max 400 ft ABOVE ALLOWED 14 CFR §107.51(b) — Maximum altitude: 400 ft AGL, or 400 ft above structure if within 400 ft radius

14 CFR 107.51(b) establishes a default maximum altitude of 400 feet above ground level (AGL) for all small UAS operations. However, this limit is subject to an important exception:

A small UAS may operate above 400 feet AGL if it is flown within 400 feet laterally of a structure and does not exceed 400 feet above the structure's uppermost limit.

This structure exception allows inspections of towers, buildings, antennas, and other vertical structures that exceed 400 feet in height. The formula for calculating the maximum permissible altitude is:

Maximum Altitude AGL = Structure Height AGL + 400 feet

Examples:

A 250-foot tower: 250 + 400 = 650 feet AGL maximum, provided the sUAS remains within 400 feet horizontally of the tower. Note that the lateral distance requirement is 400 feet, so operating at 200 feet, 150 feet, or 80 feet horizontally from the structure all satisfy the requirement.
A 400-foot tower: 400 + 400 = 800 feet AGL maximum, provided the sUAS remains within 400 feet horizontally.
A 650-foot tower: 650 + 400 = 1,050 feet AGL maximum, provided the sUAS remains within 400 feet horizontally.

The exception applies in all airspace classes where flight is otherwise permitted. No waiver is required when operating under the structure exception in Class G airspace, provided the flight remains within the lateral and vertical limits described.

Night Operations

14 CFR 107.29 permits small UAS operations at night under specific conditions. The regulatory requirements for night flight are:

The small UAS must be equipped with anti-collision lighting that is visible for at least 3 statute miles.
The remote pilot must have completed the required night operations training and knowledge requirements found in 14 CFR 107.73.
The anti-collision light must be operational and functioning at the required visibility distance during the entire night operation.

An anti-collision light visible for 2.5 statute miles is not sufficient; the minimum is 3 statute miles. A visual observer, low aircraft weight, or the absence of airspace authorization requirements does not substitute for the anti-collision light requirement. Night is defined as the time between sunset and sunrise.

Operations Over People

14 CFR 107.39 prohibits operating a small UAS directly over a person unless that person is directly participating in the operation or is located under a covered structure or within a stationary vehicle that provides protection. For operations over crowds, such as a crowded parking lot during an airshow, a remote pilot must not fly unless:

The sUAS meets an applicable Category 1 through 4 requirement under the FAA's Operations Over People rules, including compliance with means of compliance accepted by the FAA, or
The flight is conducted under an approved FAA waiver.

A valid airspace authorization under 14 CFR 107.41 does not authorize operations over people. Even if the aircraft weighs only 1.5 pounds—which would qualify as Category 1—the remote pilot must verify all applicable category requirements are met before operating over persons. The safest and most compliant action is to refuse the operation until compliance is established.

Operations from a Moving Vehicle

14 CFR 107.25 permits the remote pilot to operate a small UAS from a moving vehicle or aircraft only under specific conditions:

The operation must be conducted over a sparsely populated area.
The remote pilot must be directly responsible for the UAS and not serving as a driver or operator of the moving conveyance.
Visual line of sight requirements continue to apply.

Operating from a moving vehicle for a pipeline inspection in a rural, sparsely populated area is permissible, provided the other conditions are met.

ATC Instructions and Controlled Airspace Operations

When operating within controlled airspace under an authorization, the remote pilot is required under 14 CFR 107.43 to comply with all ATC instructions. This includes instructions to change course, exit the airspace, hold position, or alter altitude.

The remote pilot must comply promptly with ATC instructions.
The only exception is when compliance would endanger the aircraft or the safety of people or property. In that case, the remote pilot must immediately notify ATC and explain the deviation.
If ATC instructs the pilot to exit the airspace and the battery is low but still sufficient to comply, the pilot must comply with the instruction while communicating the battery concern so ATC can clear traffic and facilitate a safe exit. Refusal to comply because of a potential future emergency is not permitted when the instruction can still be executed.
The remote pilot is not required to carry a Mode C transponder or ADS-B Out when operating in Class B airspace. The transponder and ADS-B Out equipage requirements of 14 CFR 91.215 and 91.225 apply to manned aircraft operations, not to small UAS under Part 107. However, the airspace authorization requirement under 14 CFR 107.41 still applies.

Preflight Planning and NOTAM Awareness

Remote pilots are responsible for conducting a thorough preflight review that includes checking all applicable Notices to Air Missions (NOTAMs) and temporary flight restrictions in the area of operation. This obligation is explicit in 14 CFR 107.49 and reinforced by 14 CFR 107.45.

A remote pilot must review NOTAMs before every flight.
If a TFR is discovered during preflight planning, the pilot must determine whether it is active at the planned time of operation.
If a TFR is active in the operating area—including within a 5-nautical-mile radius or any other specified dimension—the flight may not occur unless specifically authorized by the FAA or the TFR NOTAM.
If a TFR becomes active during flight, the remote pilot must land as soon as practicable and not resume operations until the TFR has expired.
Local law enforcement, verbal approvals from a control tower, or operations below 400 feet AGL do not authorize operations within an active TFR.
The remote pilot is responsible for checking TFRs as part of the preflight briefing. Flight Service station briefings include TFR information, but the pilot must independently verify the current status of all applicable restrictions.

Airspace Chart Symbols Quick Reference

Airspace Chart Symbols Quick Reference Scanner Airspace Chart Symbols Quick Reference Scanner FAA Part 107 Airspace Class Chart Symbol Authorization Mini Chart Icon Class A 18,000–FL600 MSL Solid Blue NO FL180 Class B Surface–10,000 MSL Solid Blue YES SFC Class C Surface–4,000 AGL Solid Blue YES CTA Class D Surface–2,500 AGL Dashed Blue YES CTR Class E Surface or aloft Dashed Magenta YES Echo Class G Uncontrolled No depicted line YES No symbol 14 CFR Part 107 · FAA-G-8082-17B

Understanding the chart symbols for airspace is a core competency for the Part 107 knowledge test and for practical flight planning.

Airspace ClassChart DepictionAuthorization Required?
Class BSolid blue linesYes, under 107.41
Class CDashed blue linesYes, under 107.41
Class DDashed magenta linesYes, under 107.41 during tower hours
Class E (surface area)Solid magenta lines around an airportYes, under 107.41
Class E (700/1,200 ft AGL)Dashed magenta lines or blue shadingOnly above 700/1,200 ft AGL; not below
Class GNo boundary lines; uncontrolledNo authorization required
MOAMagenta hatched boundary with labelNo authorization required (special use airspace)
TFRAnnounced via NOTAM, not chartedProhibited without specific FAA authorization

Sectional Charts and Controlled Airspace Identification

When planning a flight near an airport, the remote pilot must examine the sectional chart to identify the airspace classification:

Solid blue lines around an airport indicate Class B airspace. The airport is one of the busiest in the country, and authorization must be obtained before operating inside the lateral boundaries.
Dashed blue lines indicate Class C airspace. The airport has an operational control tower and radar approach control, and authorization is required.
Dashed magenta lines indicate Class D airspace. The airport has a control tower, and authorization is required during the tower's published hours of operation.
A segmented blue or magenta circle around the airport symbol without full airspace boundaries indicates a Class D airspace area that may not extend to the surface in all directions, but the authorization requirement still applies within the lateral boundaries during tower hours.
Solid magenta lines indicate a Class E surface area designated for an airport. Authorization is required within these boundaries.
The absence of any controlled airspace boundaries around an airport indicates the surrounding airspace is uncontrolled Class G or controlled Class E beginning at 700 or 1,200 feet AGL, which requires no authorization for operations below those altitudes.

Common Misconceptions and Pitfalls

"I'm only flying at 200 feet, so I don't need authorization." This is incorrect. The authorization requirement in 107.41 applies regardless of planned altitude when operating within the lateral boundaries of Class B, C, D, or surface-level E airspace.
"The tower said it was okay over the phone." Verbal approvals are not valid airspace authorizations. Authorization must be obtained through LAANC or DroneZone.
"A TFR doesn't apply to small drones below 400 feet." TFRs apply to all aircraft, including small UAS, at all altitudes. There is no exemption for low-altitude operations.
"The structure exception means I can fly 400 feet above any tower, anywhere." The exception requires the sUAS to be within 400 feet laterally of the structure. The vertical allowance is only available while the aircraft remains within the horizontal boundary.
"Class G airspace means I don't have any rules." Class G only means no ATC authorization is required. All other Part 107 operating limitations—right-of-way, visibility, cloud clearance, altitude, speed, and TFR compliance—still apply.
"I need ADS-B Out to fly in Class B." Part 107 does not require transponder or ADS-B Out equipage on small UAS. However, authorization is still mandatory.
"An MOA is controlled airspace, so I need authorization." MOAs are special use airspace, not controlled airspace. No airspace authorization is required, but the remote pilot must remain clear of military activities and yield to military aircraft.

Review of Key Regulatory Citations

RegulationSubject Matter
14 CFR 107.25Operation from a moving vehicle only over sparsely populated areas
14 CFR 107.29Night operation anti-collision light (3 SM) and training requirements
14 CFR 107.37Right of way; yield to all other aircraft
14 CFR 107.39Operations over people prohibition
14 CFR 107.41No operation in controlled airspace without prior ATC authorization
14 CFR 107.43Compliance with ATC instructions
14 CFR 107.45No operation in restricted areas, prohibited areas, or TFRs
14 CFR 107.51Operating limitations: speed (87 kts), altitude (400 ft AGL + structure exception), visibility (3 SM), cloud clearance (500 ft below, 2,000 ft horizontal)
14 CFR 107.73Knowledge and training requirements, including night operations
Chapter 2Remote ID and Operations Over PeopleChapter 4Sectional Charts and Aeronautical Symbols

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