National Airspace Classifications

Operating Requirement and Flight Restrictions
National Airspace System (NAS)

Remote pilots must learn and understand the various airspace classes within the National Airspace System (NAS). This airspace is divided into two categories: regulatory and nonregulatory . Within these two categories there are four types of airspace: controlled, uncontrolled, special use, and other airspace. The NAS is comprised of class A, class B, class C, class D, class E, and class G airspace however part 107 only requires the knowledge of classes B through G airspace. Class B, C, D, E and G airspace fall under regulatory airspace governed by the FAA, and nonregulatory airspace includes prohibited, restricted, warning, military operation alert areas, and controlled firing areas where the FAA does not enforce.

Controlled Airspace: Controlled airspace is a generic term that covers the different classifications of airspace and defined dimensions within which air traffic control (ATC) service is provided in accordance with the airspace classification. Controlled airspace that is of concern to the remote pilot is: Class B, Class C, Class D, and Class E. Because this lesson is complex and complicated, we encourage students to watch the video tutorial.

A remote pilot must receive FAA authorization before operating in any controlled airspace.

Class B Airspace

Class B Airspace is generally airspace that runs from the surface (SFC) of the airport up to 10,000 feet mean sea level (MSL) and surrounds some of the nation’s busiest passenger airports such as Chicago O’Hare, Los Angeles, and Dallas/Fort Worth. Class B Airspace is individually configured based upon an area’s natural terrain and manmade objects, and consists of a surface area with two or more layers resembling an upside-down wedding cake. The center of Class B Airspace extends outward about 5 miles from the center of the airport and extends upward to around 10,000 feet MSL. The altitude can vary depending on location of an airport, so these are typical/average numbers. The first larger shelf of airspace typically begins at 1,200 feet MSL and extends up to 10,000 feet MSL and outward about 10 miles from the center of the airport. The second shelf of airspace typically begins at around 3,500 to 4,000 feet MSL and extends up to 10,000 feet MSL and outward about 15 miles from the center of the airport.

Class C Airspace

Class C Airspace is generally airspace from the surface (SFC) of the airport up to about 4,000 feet mean sea level (MSL), and usually consists of a surface area that extends outward five-nautical mile (NM) from the center of the airport. The ceiling of the airspace can vary depending upon the surrounding natural terrain and manmade objects, and the ceiling could be 4,100 MSL or perhaps 3,800 feet MSL. But on average, the ceiling of Class C Airspace extends up to 4,000 MSL. There’s typically a first shelf of airspace that begins at 1,200 feel MSL and extends up to about 4,000 MSL with a ten NM radius.

Class D Airspace

Class D Airspace is generally airspace that runs from the surface at the airport to 2,500 feet MSL, and surrounds airports that have an operational control tower. Class D airspace typically consists of a surface area within a five-nautical mile radius from the center of the airport and the configuration of Class D Airspace is also individually tailored depending on the airport’s elevation and natural terrain or manmade objects.

When the air traffic control tower is closed, or outside operating control tower hours, Class D Airspace has a part time operating control tower, Class D Airspace becomes Class G Airspace. As with any controlled airspace, the remote pilot in command must obtain FAA authorization before operating in any controlled airspace.

Class E Airspace

Class E Airspace is perhaps one of the most confusing airspace classifications as it’s comprised of three (3) airspace classifications where each airspace pertains to different altitudes. One type of Class E Airspace is denoted with a dashed or segmented magenta circle/lines in an aeronautical sectional chart, and typically begins at the surface and will extend to an altitude depending on other airspace depicted in the sectional chart, typically Class G airspace at 1,200 feet AGL or upwards to 17,999 feet MSL (the bottom of Class A Airspace). This airspace can be single out around an airport, or it can also be attached to Class D Airspace.

Class E Airspace can also be represented as a shaded magenta circle with the inside of the airspace starting at 700 feet AGL and extending up to the next overlying airspace such as the bottom of Class B, Class C, or perhaps uncontrolled Class G Airspace. Class E Airspace can also be shown as a shaded blue circle or shape beginning at 14,500 feet MSL, or 1,200 feet MSL. However, shaded blue Class E Airspace is mostly seen in the western United States at higher elevations.

Class G Airspace / Uncontrolled Airspace

Class G Airspace is the portion of the airspace that has not been designated, and extends from the surface to the base of the overlying Class E Airspace. A remote pilot will not need authorization to operate in Class G Airspace.

Special Use Airspace

Special use airspace, or special area of operation (SAO), is the designation for airspace in which certain activities must be confined, or where limitations may be imposed on aircraft operations that are not part of those activities. Special use airspace usually consists of:

• Prohibited Areas
• Restricted Areas
• Warning Areas
• Military Operation Areas (MOAs)
• Alert Areas
• Controlled Firing Areas (CFAs)

Prohibited Areas
Prohibited areas contain airspace of defined dimensions where the flight of aircraft is prohibited for security reasons, or other reasons associated with the national welfare. The area is charted as a “P” followed by a number (e.g., P-40), and an example of a prohibited area would be Camp David.

Restricted Areas
Restricted areas are areas where operations are hazardous to nonparticipating aircraft. Restricted areas denote the existence of unusual and often invisible hazards to aircraft such as artillery firing, aerial gunnery, or guided missiles. Penetration of restricted areas without authorization from the using or controlling agency may be extremely hazardous to the aircraft. Restricted areas are charted with an “R” followed by a number (i.e.: R-4401).

Warning Areas
Warning areas are similar in nature to restricted areas however, the United States government does not have sole jurisdiction over the airspace. A warning area is airspace of defined dimensions, extending from 3 NM outward from the coast of the United States, containing activity that may be hazardous to nonparticipating aircraft. The purpose of such areas is to warn nonparticipating pilots of the potential danger. A warning area may be located over domestic or international waters or both. The airspace is designated with a “W” followed by a number (i.e.: W-237).

Military Operation Areas (MOAs)
MOAs consist of airspace with defined vertical and lateral limits established for the purpose of separating certain military training activities from instrument flight rules traffic (IFR). Whenever an MOA is being used, nonparticipating IFR traffic may be cleared through an MOA if IFR separation can be provided by air traffic control (ATC). Otherwise, ATC reroutes or restricts nonparticipating IFR traffic. MOAs are depicted on a sectional chart, VFR terminal areas, and enroute low altitude charts and are not numbered (i.e.: Camden Ridge MOA).

Alert Areas
Alert areas are depicted on aeronautical charts with an “A” followed by a number (i.e.: A-211) to inform nonparticipating pilots of areas that may contain a high volume of pilot training or an unusual type of aerial activity. Pilots should exercise caution in alert areas. All activity within an alert area shall be conducted in accordance with regulations, without waiver, and pilots of participating aircraft, as well as pilots transiting the area, shall be equally responsible for collision avoidance.

Controlled Firing Area (CFA)
CFA’s contain activities that, if not conducted in a controlled environment, could be hazardous to nonparticipating aircraft. The difference between a CFA and other special use airspace is that activities must be suspended when a spotter aircraft, radar, or ground lookout position indicates an aircraft might be approaching the area. There is no need to chart CFA’s, since they do not cause a nonparticipating aircraft to change its flight path.

Other Airspace Areas
Other airspace areas is a general term referring to the majority of the remaining airspace. It includes:

• Local airport advisory (LAA)
• Military training route (MTR)
• Temporary flight restriction (TFR)
• Parachute jump aircraft operations
• Published VFR routes
• Terminal radar service area (TRSA)
• National security area (NSA)
• Air Defense Identification Zones (ADIZ) land and water based and need for Defense VFR (DVFR) flight plan to operate VFR in this airspace
• Flight Restricted Zones (FRZ) in vicinity of Capitol and White House
• Wildlife Areas/National Parks and request to operate above 2,000 AGL
• National Oceanic and Atmospheric Administration (NOAA) Marine Areas off the coast with requirement to operate above 2,000 AGL
• Tethered balloons for weather recordings extending on cables up to 60,000 feet
• Local Airport Advisory (LAA)

Advisory services provided by Flight Service Facilities (aka Flight Service) are located at the landing airport and use a discrete ground-to-air frequency or the tower frequency when the tower is closed.  Local Airport Advisory services (LAA) include local airport advisories, automated weather reporting with voice broadcasting, a continuous Automated Surface Observing System (ASOS), Automated Weather Observing Station (AWOS) data display, other continuous direct reading instruments, or manual observations available to the specialist.

Military Training Routes (MTR)
MTRs are routes used by military aircraft to maintain proficiency in tactical flying. These routes are usually established below 10,000 feet MSL for operations at speeds in excess of 250 knots. Some route segments may be defined at higher altitudes for purposes of route continuity. Routes are identified as IFR (IR), and VFR (VR). MTRs with no segment above 1,500 feet AGL are identified by four number characters (e.g., IR1206, VR1207). MTRs that include one or more segments above 1,500 feet AGL are identified by three number characters (e.g., IR206, VR207).

IFR low altitude enroute charts depict all IR routes and all VR routes that accommodate operations above 1,500 feet AGL. IR routes are conducted in accordance with IFR regardless of weather conditions. VFR sectional charts depict military training activities, such as IR, VR, MOA, restricted area, warning area, and alert area information.

Temporary Flight Restrictions
Temporary Flight Restrictions (TFR) are issued using Notice to Airmen (NOTAM) and are obtained by several methods, but the most preferred is 1800wxbrief.com.  Some of the purposes for establishing a TFR are:

• Protect persons and property in the air or on the surface from an existing or imminent hazard.
• Provide a safe environment for the operation of disaster relief aircraft.
• Prevent an unsafe congestion of sightseeing aircraft above an incident or event, that may generate a high degree of public interest.
• Protect declared national disasters for humanitarian reasons in the State of Hawaii.
• Protect the President, Vice President, or other public figures.
• Provide a safe environment for space agency operations.
• Parachute Jump Aircraft Operations.

Calling 1-800-wxbrief (1-800-992-7433) is the least recommended as that number is typically utilized by private and commercial manned pilots. Other sources are:
https://tfr.faa.gov/tfr2/list.html
https://www.notams.faa.gov
www.iflightplanner.com/AviationCharts/

SkyVector.com is another great resource as they provide accurate and fast access to NOTAM’s, as well as Chart Supplements U.S. for detailed airport information too. Parachute jump aircraft operations are published in the Chart Supplement U.S. (formerly Airport/Facility Directory) and these jump sites are dented within Aeronautical Sectional Charts.

Published VFR Routes: Published VFR routes are for transitioning around, under, or through some complex airspace. Terms such as VFR flyway, VFR corridor, Class B airspace VFR transition route, and terminal area VFR route have been applied to such routes. These routes are generally found on VFR terminal area planning charts.

Terminal Radar Service Areas (TRSA’s): TRSA’s are areas where participating pilots can receive additional radar services. The purpose of the service is to provide separation between all IFR operations and participating VFR aircraft. The primary airport(s) within the TRSA become(s) Class D airspace. The remaining portion of the TRSA overlies other controlled airspace, which is normally Class E airspace beginning at 700 or 1,200 feet and established to transition to/from the enroute terminal environment. TRSA’s are depicted on VFR sectional charts and terminal area charts with a solid grey line/circle and altitudes for each segment. The Class D portion is charted with a blue segmented line. Participation in TRSA services is voluntary; however, pilots operating under VFR are encouraged to contact the radar approach control and take advantage of TRSA service.

National Security Areas (NSA’s): NSA’s consist of airspace of defined vertical and lateral dimensions established at locations where there is a requirement for increased security and safety of ground facilities. Flight in NSA’s may be temporarily prohibited by regulation under the provisions of Title 14 of the Code of Federal Regulations (14 CFR) part 99, and prohibitions are disseminated via NOTAM’s. Pilots are requested to voluntarily avoid flying through these depicted areas.

It’s worth noting again that flying your sUAS in a National Park such as Yellowstone National Park, or a National Monument such a Fort Monroe in Hampton Virginia or Devil’s Tower in Wyoming is prohibited.  As with all flight operations, the remote pilot in command (PIC) should refer to current aeronautical charts and other navigation tools to determine position and related airspace.

Obtaining Airspace Authorizations
As of late 2017 through 2018, the FAA has changed how remote pilots request authorization to fly in a controlled airspace. In the past, a remote pilot would call Air Traffic Control (ATC) directly and verbally request approval. As of February 2018, authorization is now obtained via the FAA Drone Zone website at https://faadronezone-access.faa.gov. This is the same website where you are required to register your drone.

Notices to Airmen (NOTAM): Temporary Flight Restrictions (TFR) are inclusive of sUAS operations. For that reason, it is necessary for the Remote PIC to check for Notices to Airmen (NOTAM) before each flight to determine if there are any applicable airspace restrictions. Common TFRs that relate to sUAS operations include, but are not limited to:

Presidential TFRs and NOTAM
Emergency response TFRs and NOTAMs
Standing TFRs that go into and out of effect (e.g., stadiums for sporting events)

Obtain current NOTAM and TFR information from:
https://tfr.faa.gov/tfr2/list.html
https://skyvector.com/

Congratulations! You’ve finished Lesson 2 on Airspace Classifications. Be sure to click the COMPLETE button below to register your progress.