2.1 National Airspace System Overview
Key Takeaways
- The NAS is divided into six airspace classes: A through E (controlled) and G (uncontrolled).
- Part 107 drones need authorization for Class B, C, D, and surface area of Class E — NOT for Class G.
- Prohibited Areas never permit flight; Restricted Areas require permission from the controlling agency.
- Always check NOTAMs for Temporary Flight Restrictions (TFRs) before every flight.
- Special Use Airspace includes Prohibited, Restricted, Warning, MOA, Alert, and Controlled Firing Areas.
2.1 National Airspace System Overview
The National Airspace System (NAS) is the complex network of airspace, navigation facilities, airports, and air traffic management that enables safe and efficient air travel in the United States. As a remote pilot, understanding how airspace is classified and regulated is essential — airspace questions typically make up 15-25% of the Part 107 exam.
Airspace Classification System
The U.S. uses the International Civil Aviation Organization (ICAO) airspace classification system, dividing airspace into six classes designated by letters A through E (controlled) and G (uncontrolled):
| Class | Type | Location | ATC Service | UAS Relevance |
|---|---|---|---|---|
| A | Controlled | 18,000 ft MSL to FL600 | Required | Not applicable (above Part 107 limits) |
| B | Controlled | Major airports | Required | Authorization required |
| C | Controlled | Busy airports | Required | Authorization required |
| D | Controlled | Airports with control towers | Required | Authorization required |
| E | Controlled | Various (transition, en route) | As needed | Authorization required for surface area |
| G | Uncontrolled | Surface to various altitudes | Not provided | No authorization needed |
The Inverted Wedding Cake Model
The NAS airspace around airports is commonly visualized as an inverted wedding cake — layers of controlled airspace that get wider as altitude increases, centered on the airport.
Controlled vs. Uncontrolled Airspace
Controlled Airspace (Classes A, B, C, D, E):
- Air Traffic Control (ATC) provides some level of service
- Aircraft must meet specific equipment, pilot qualification, and communication requirements
- Part 107 drones need authorization to operate in Class B, C, D, and the surface area of Class E airspace designated for an airport
Uncontrolled Airspace (Class G):
- ATC does not provide separation services
- Pilots are responsible for their own separation from other aircraft
- Part 107 drones can operate freely in Class G airspace (subject to all other rules)
For the Exam: The critical rule is simple — if it is controlled airspace with a surface area designation, you need authorization. Class G = no authorization needed.
Special Use Airspace
In addition to the standard classes, there are Special Use Airspace (SUA) designations that restrict or prohibit flight:
| Type | Symbol on Chart | Description | UAS Operations |
|---|---|---|---|
| Prohibited Area | P-XX (blue hatching) | Flight prohibited for security/national welfare | Never permitted |
| Restricted Area | R-XX (blue hatching) | Hazardous activities (military, weapons testing) | Need permission from controlling agency |
| Warning Area | W-XX (blue hatching) | Hazardous activities over international waters | Exercise caution |
| Military Operations Area (MOA) | Magenta hatching | Military flight training | No authorization required, but exercise extreme caution |
| Alert Area | Magenta hatching | High volume of pilot training or unusual activity | No authorization required, but exercise caution |
| Controlled Firing Area (CFA) | Not charted | Active when firing; ceases when aircraft detected | Not charted — operations cease when IFR/VFR traffic approaches |
Other Airspace Designations
Temporary Flight Restrictions (TFRs):
- Temporary airspace restrictions for events like presidential movement, natural disasters, sporting events, or emergency operations
- Always check NOTAMs for active TFRs before every flight
- Violating a TFR can result in certificate action, fines, and potentially criminal charges
National Security Areas (NSAs):
- Areas where increased security and safety of ground facilities is required
- Voluntary compliance requested (though the FAA can make them mandatory with a NOTAM)
Wildlife Refuges:
- Many national wildlife refuges prohibit drone operations
- Always check with local authorities before flying in or near wildlife areas
In which class of airspace can a Part 107 drone operate WITHOUT prior authorization?
What type of special use airspace is NEVER available for drone operations?