Definition
A defined area of airspace established at locations where there is a requirement for increased security and safety of ground facilities. Pilots are requested to voluntarily avoid flying through the depicted NSA. When a greater level of security is needed, flight in an NSA may be temporarily prohibited by regulation under FAR 99.7. NSAs are charted on aeronautical charts with their vertical and lateral limits.
Plain English
A patch of airspace around a sensitive ground site — like a military base or government facility — where pilots are asked to stay out for security reasons. Most of the time the request is voluntary, but the FAA can make it a hard rule when the situation calls for it.
Context Anchor
Seen on aeronautical charts and in preflight planning near sensitive facilities or locations with special security concerns.
Why Pilots Care
Unauthorized entry can trigger interception by military aircraft and result in regulatory violations.
Intuition Check
Do not assume a National Security Area is always completely closed airspace. Usually it is an area pilots are asked to avoid, but it can become temporarily prohibited when security requires it.
Example Sentence 1
While planning the cross-country, the student noticed an NSA depicted around the naval weapons facility and adjusted the route to give it a wide berth.
Example Sentence 2
ATC confirmed the NSA was active and directed the aircraft to remain clear.