 Alert Areas Alert areas are depicted on sectional charts with an “A”  followed by a number (e.g., “A-211” as in  Figure 8-16 ) 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 fl ying in  these areas. All activity within an alert area shall be conducted  in accordance with regulations, without waiver. Pilots of  participating aircraft, as well as pilots transiting the area,  shall be equally responsible for collision avoidance.  MOA,” “RANCH HIGH & RANCH MOA” and “RANCH  MOA”).  [Figure 8-14]  MOA is further defined on sectional  charts with times of operation, altitudes affected, and the  controlling agency frequency for the MOA to contact for  current activity.  [Figure 8-15] Controlled firing areas contain military activities, which,  if not conducted in a controlled environment, could be  hazardous to nonparticipating aircraft. The difference  between controlled firing areas and other special use airspace  is that activities must be suspended when a spotter aircraft,  Figure 8-16.  Alert area (A-211). Figure 8-14.  Special use airspace: restricted and MOA examples. Figure 8-15. MOA is further defined on sectional charts with times of operation, altitudes  affected, and the controlling agency to contact for current activity.  Controlled Firing Areas 8-10