Special Use Airspace (SUA) – Aviation Operations Glossary

Special Use Airspace (SUA) is a collective term for airspace where flight operations are restricted, segregated, or subject to special rules due to reasons of national security, military necessity, safety, or unique operational requirements. Understanding each SUA type is essential for safe and legal flight operations, whether for pilots, flight planners, or aviation professionals.

Prohibited Areas

Prohibited Areas represent the strictest form of airspace restriction. These areas are established to protect national interests or sensitive facilities vital to U.S. security and welfare. Under 14 CFR Part 73, Subpart C, the FAA, often at the request of military or security agencies, designates Prohibited Areas with the prefix “P-” (e.g., P-40 for Camp David, Maryland).

No aircraft may enter a Prohibited Area unless on an expressly authorized government mission. This applies to both VFR and IFR operations; even emergencies require immediate ATC notification and subsequent reporting. Prohibited Areas are always regulatory, permanently active (unless noted otherwise), and are depicted on aeronautical charts with clearly defined boundaries and vertical limits.

Violations can trigger immediate military response, interception, and severe penalties, including certificate suspension, fines, or prosecution.

Restricted Areas

Restricted Areas are established where activities hazardous to nonparticipating aircraft (artillery firing, missile launches, military exercises) occur. While not categorically forbidden, entry is tightly controlled. They are regulatory, depicted with “R-” followed by a number (e.g., R-2515), and have published boundaries, altitudes, and times of use.

IFR flights may be cleared through when the area is inactive or released to ATC. VFR pilots must contact the controlling agency for real-time status and possible clearance. Restricted Areas protect both civilian traffic and military or scientific operations.

Unauthorized entry is dangerous and subject to enforcement, including military interception.

Warning Areas

Warning Areas begin three nautical miles off the U.S. coast, extending over domestic and international waters. These nonregulatory areas warn pilots of hazardous activity (military exercises, missile launches, supersonic flight) outside domestic airspace jurisdiction. They are depicted with a “W-” prefix (e.g., W-291A).

Entry is not prohibited, but pilots should exercise extreme caution. The controlling agency (often Navy or Air Force) provides status via the charted frequency. Risks can be as great as active Restricted Areas.

Military Operations Areas (MOAs)

Military Operations Areas (MOAs) separate military training (high-speed, aerobatic maneuvers) from IFR traffic. MOAs are nonregulatory; VFR traffic may transit without clearance but should be vigilant and contact the controlling agency for advisories.

IFR flights are routed through MOAs only if ATC provides separation from military activity. MOAs are depicted in magenta, with names (e.g., “Pine Hill MOA”), boundaries, vertical limits, and controlling agency listed.

Alert Areas

Alert Areas notify pilots of high-density flight training or unusual aerial activity (gliders, aerobatics, parachute jumps). Labeled “A-” (e.g., A-211), these nonregulatory areas have no entry restrictions, but all pilots must exercise increased vigilance and comply with standard see-and-avoid rules.

Boundaries, vertical limits, and activity details are published on charts and in the legend.

Controlled Firing Areas (CFAs)

Controlled Firing Areas (CFAs) are unique: they’re not charted. Hazardous activities (artillery, ordnance disposal) occur here, but are immediately suspended when nonparticipating aircraft approach. Detection relies on ground observers or radar.

There are no restrictions or entry requirements for nonparticipants; pilots are generally unaware of a CFA’s existence unless participating in the operations.

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National Security Areas (NSAs)

National Security Areas (NSAs) are established to protect ground facilities critical to national interests. NSAs are nonregulatory (unless a TFR is issued) and depicted with magenta dashed boundaries. Pilots are strongly requested to avoid flight below specified altitudes as noted in the chart margin.

Facilities include nuclear plants, sensitive military or research installations. During heightened security, a TFR can make entry legally prohibited.

Military Training Routes (MTRs)

Military Training Routes (MTRs) facilitate high-speed, low-level military training. Two categories exist: Instrument Routes (IR) for IFR, and Visual Routes (VR) for VFR. Three-digit numbers indicate operations above 1,500’ AGL; four digits are at/below 1,500’ AGL.

MTRs appear as thin gray lines on charts, labeled (e.g., VR2054). Military aircraft may exceed 250 knots below 10,000’ MSL.

Temporary Flight Restrictions (TFRs)

Temporary Flight Restrictions (TFRs) are short-term, regulatory airspace blocks established via NOTAM under 14 CFR 91.137–145. TFRs protect people and property during special events, emergencies, disasters, VIP travel, or hazardous conditions.

TFRs are not shown on printed charts; always check FAA NOTAMs, Flight Service, or your EFB before flight. Unauthorized entry is subject to enforcement and severe penalties.

Parachute Jump Areas

Parachute Jump Areas are established for regular parachuting activity. They’re depicted with a parachute symbol on Sectionals and detailed in the Chart Supplement. Information includes location, times, and advisory frequencies.

Pilots should monitor the CTAF or advisory frequency, avoid the area during active jumps, and maintain vigilance for jump aircraft.

VFR Routes

VFR Routes help pilots navigate safely through or around complex airspace, especially Class B. Types include:

• VFR Flyways: Suggested paths avoiding Class B, no ATC clearance needed.
• VFR Corridors: Tunnels through Class B, no clearance but strict adherence to published routing and altitudes.
• Class B Transition Routes: Specific routes through Class B, ATC clearance required.

Routes are depicted on Terminal Area Charts (TACs) with labels, altitudes, and reporting points.

Conclusion

Special Use Airspace is a foundational concept for safe aviation in the United States and abroad. Each SUA type serves a specific function—protecting national security, enabling military operations, enhancing public safety, or accommodating unique activities. Pilots and flight planners must know how to identify, interpret, and comply with SUA rules using current charts, NOTAMs, and official data sources.

Failure to respect SUA boundaries can result in dangerous situations, legal repercussions, and national security concerns. Always check for SUAs during preflight planning, use up-to-date navigation tools, and maintain vigilance when operating near or within special airspace.

For more information, consult the FAA’s Aeronautical Information Manual (AIM), current aeronautical charts, and the FAA SUA website.

Related terms:
Airspace Classes | NOTAM | TFR | Chart Supplement | Sectional Chart s](/glossary/airspace-classes/) | NOTAM | TFR | Chart Supplement | Sectional Chart