Sectional chart reference

Alert Area (A-###)

Magenta hatched boundary.

Alert Area (A-###) as printed on a VFR sectional chart: Magenta hatched boundary. The illustration shows a boundary line with hatching on the inside of the area. A-231
Drawn to the depiction described in the FAA Aeronautical Chart Users’ Guide, effective 9 July 2026. Illustrative, not to scale, and not for navigation.

What you are looking at

High volume of pilot training or unusual aerial activity; all pilots stay alert.

FloorPublished
CeilingPublished
Part 107 at 400 ft No ATC authorization required, but check before you fly
Source: depiction per the FAA Aeronautical Chart Users’ Guide, effective 9 July 2026 (PDF).

What that verdict means here

§ 107.41 does not require an authorization here, and that is not the same as the area being safe. Military or hazardous activity may be underway. Read the times of use on the chart panel and check NOTAMs.

⚠️ § 107.41, the ATC-authorization rule quoted on the Class B, C, D and E-surface pages, is not the rule that governs this symbol, which is why it is not quoted here.

Find one near you

Reading about a symbol is not the same as finding it. Open the live chart, put in your own address, and see what is actually there.

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Not for navigation. Study material, not authority. This page explains a chart symbol for study. It is not an authorization source and not a substitute for an official pre-flight check. Confirm on the FAA’s own chart viewer and through LAANC before you fly.

Related symbols

Prohibited Area (P-###)Restricted Area (R-###)Warning Area (W-###)Military Operations Area (MOA)National Security Area (NSA)

See all 19 symbols →