Chapter 2: Airspace Classification, Operating Requirements, and Flight Restrictions Alert Areas Controlled Firing Areas (CFAs) Other Airspace Areas  Figure 2-6.  Alert area (A-211). CFAs contain activities that, if not conducted in a controlled environment, could be hazardous to  nonparticipating aircraft. The difference between CFAs and other special use airspace is that  activities must be suspended when a spotter aircraft, radar, or ground lookout position indicates 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. “Other airspace areas” is a general term referring to the majority of the remaining airspace. It includes: is also further defined on the back of the sectional charts with times of operation, altitudes affected,  and the controlling agency. Alert areas are depicted on aeronautical charts with an “A” followed by a number (e.g., A-211) to  inform nonparticipating pilots of areas that may contain a high volume of pilot training or an  unusual type of aerial activity. Pilots should exercise caution in alert areas. All activity within an alert  area shall be conducted in accordance with regulations, without waiver, and pilots of participating  aircraft, as well as pilots transiting the area, shall be equally responsible for collision avoidance.  [Figure 2-6]  Remote Pilot – Small Unmanned Aircraft Systems Study Guide  9  • Parachute jump aircraft operations • Published VFR routes • Terminal radar service area (TRSA) • National security area (NSA) • Air Defense Identification Zones (ADIZ) land and water based and need for Defense VFR  (DVFR) flight plan to operate VFR in this airspace • Flight Restricted Zones (FRZ) in vicinity of Capitol and White House • Local airport advisory (LAA) • Military training route (MTR) • Temporary flight restriction (TFR)