Restricted areas are charted with an “R” followed by a  number (e.g., R-4401) and are depicted on the en route  chart appropriate for use at the altitude or FL being flown.  [Figure 15-3]  Restricted area information can be obtained  on the back of the chart.  Warning areas are similar in nature to restricted areas;  however, the United States government does not have sole  jurisdiction over the airspace. A warning area is airspace of  defined dimensions, extending from 3 NM outward from  the coast of the United States, containing activity that may  be hazardous to nonparticipating aircraft. The purpose of  such areas is to warn nonparticipating pilots of the potential  danger. A warning area may be located over domestic or  international waters or both. The airspace is designated with  a “W” followed by a number (e.g., W-237).  [Figure 15-4]  MOAs consist of airspace with defined vertical and lateral  limits established for the purpose of separating certain  military training activities from IFR traffic. Whenever an  MOA is being used, nonparticipating IFR traffic may be  cleared through an MOA if IFR separation can be provided by  ATC. Otherwise, ATC reroutes or restricts nonparticipating  IFR traffic. MOAs are depicted on sectional, VFR terminal  area, and en route low altitude charts and are not numbered  (e.g., “Camden Ridge MOA”).  [Figure 15-5]  However, the  MOA 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  “Other airspace areas” is a general term referring to the  majority of the remaining airspace. It includes:  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 15-6]  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.  Warning Areas  Military Operation Areas (MOAs)  Controlled Firing Areas (CFAs)  Alert Areas  Other Airspace Areas  Figure 15-3.  Restricted areas on a sectional chart.  15-4  •  Local airport advisory (LAA)  •  Military training route (MTR)  •  Temporary flight restriction (TFR)  •  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  • Intercept Procedures and use of 121.5 for  communication if not on ATC already  Figure 15-4.  Requirements for airspace operations. 