A National Security Area chart note that asks pilots to avoid the area is a request, not the same legal bar as a prohibited area, unless a restriction is actually in effect. Section 99.7 security airspace is a real restriction when it is published by NOTAM. Read the note, then check current notices before you fly.
What the chart is asking
The Chart Users' Guide depicts a National Security Area with a broken magenta line. The guidance to pilots is to avoid flying through the depicted area. When necessary, flight through the area may be temporarily prohibited. The depiction has vertical and lateral limits, but you do not invent a radius that the chart does not print. There is no single NSA distance to memorize for the test.
The ACS item is specific. When the chart shows an NSA with a note requesting avoidance, treat the request as a request, and review current restrictions and NOTAMs before flight. Do not assume the area is restricted airspace that always requires permission. Do not fly through it on the theory that an NSA has no significance. The note matters. It is still not a prohibited-area label unless a restriction is in effect.
Prohibited and restricted areas are a different rule, §107.45, and they are explained on the MOA and restricted area page. Stadium and event notices are a different publication path, covered under stadium restrictions. An NSA sits in the ACS list of other airspace areas alongside military training routes, TFRs, parachute-jump operations, TRSAs, and VFR routes. Those names do not share one entry test.
When the request becomes a restriction
Section 99.7 is the special security instruction authority. When security airspace is published by NOTAM under that section, it is a real restriction, not a courtesy. Section 107.47 requires the remote pilot in command to comply with §§91.137 through 91.145 and with §99.7. A temporary flight restriction drawn for national security is the notice you comply with. The chart note and the current NOTAM together tell you whether you are looking at a voluntary avoidance or at airspace that is closed.
The way you learn which one is in effect today is a briefing, not a guess from the magenta dashes. The NOTAM page is the briefing path. A saved sectional does not include this morning's security notice.
The preflight rule that assigns the check
Before flight, §107.49 requires the remote pilot in command to assess the operating environment. That assessment includes local weather conditions, local airspace and any flight restrictions, the location of people and property on the surface, and other ground hazards. The regulation that requires the weather assessment is §107.49. It is not the visual-line-of-sight rule in §107.31, and it is not the night-operations rule in §107.29. Those sections govern seeing the aircraft and operating at night. They do not assign the weather check.
The same paragraph is why the NSA note and the §99.7 NOTAM get read before launch. Airspace and flight restrictions are listed next to weather in §107.49(a). You are not finished when you have only looked at the wind.
Where the airport detail lives
A remote pilot who needs the full runway layout and the special remarks for an unfamiliar airport does not get that from a social media group or from the battery manual. The best source is the Chart Supplement. The sectional data block is a summary. Runway geometry, lighting notes, and the remarks that change how you use the field are in the supplement. That publication is covered on the Chart Supplement page. Knowing an NSA is nearby does not replace reading the airport entry if the flight is at that field.
A site next to a dashed magenta NSA
You are hired to photograph a facility just outside a broken magenta National Security Area. The chart note asks pilots to avoid the area. You plan the aircraft to stay outside the depicted boundary, because the note is a real request and "it has no significance" is not a plan. You then pull current NOTAMs. If nothing has temporarily prohibited flight, you still honor the avoidance request and you do not wander into the area for a tighter shot. If a §99.7 security NOTAM is in effect, you comply with that notice. You also read the weather under §107.49, and if the airport is unfamiliar you open the Chart Supplement for the runway layout and remarks before you brief the crew.
The trap
Calling every NSA a prohibited area adds a permission rule the note did not state. Ignoring the note, or skipping NOTAMs, drops a request that can become a real restriction under §99.7. Citing §107.31 or §107.29 as the weather rule misses §107.49. Looking up runway remarks in a forum misses the Chart Supplement. The chart asks for avoidance. The NOTAM tells you when avoidance has become a restriction.
Practice the airspace distinctions on the free practice test. The lessons that cover other airspace are in the course.