AIM Text
Alert areas are depicted on aeronautical charts to inform nonparticipating pilots of areas that may contain a high volume of pilot training or an unusual type of aerial activity. Pilots should be particularly alert when flying in these areas. All activity within an alert area must be conducted in accordance with CFRs, without waiver, and pilots of participating aircraft as well as pilots transiting the area must be equally responsible for collision avoidance.
3-4-7. Controlled Firing Areas
CFAs contain activities which, if not conducted in a controlled environment, could be hazardous to nonparticipating aircraft. The distinguishing feature of the CFA, as compared to other special use airspace, is that its activities are suspended immediately when spotter aircraft, radar, or ground lookout positions indicate an aircraft might be approaching the area. There is no need to chart CFAs since they do not cause a nonparticipating aircraft to change its flight path.
3-4-8. National Security Areas
NSAs 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. Pilots are requested to voluntarily avoid flying through the depicted NSA. When it is necessary to provide a greater level of security and safety, flight in NSAs may be temporarily prohibited by regulation under the provisions of 14 CFR section 99.7. Regulatory prohibitions will be issued by System Operations Security and disseminated via NOTAM. Inquiries about NSAs should be directed to System Operations Security.
Source: FAA Aeronautical Information Manual · current edition · paragraph 3-4-6.
Research Notes
AIM 3-4-6 covers Alert Areas — airspace with high pilot training or unusual aerial activities.
Alert area characteristics:
- Identifies areas of unusual activity (high training volume, glider ops, parachuting)
- Activities may be by civil pilots, not just military
- Both pilots in the area share responsibility for see-and-avoid
Common alert areas:
- Glider operations zones
- Active soaring areas
- High-volume training airports
Operations: Pilots may operate freely through alert areas but should be aware of the published activity type and operate cautiously.
Reference: AIM 3-4-6.