text: Drop Zones
  Figure 6-17. Drop zone placement (night).
  AUTHENTICATION
  6-125. Authentication varies for day and night operations.
  Day Operations
  6-126. During day operations, the DZSTL may authenticate or identify different sites by specifying drop
  times, drop headings, or alternating panel colors, or whatever he coordinates.
  Night Operations
  6-127. During night operations, the DZSTL may authenticate or identify different sites by replacing one
  light in the code letter with any color light except white.
  OTHER FORMS OF CARP ZONES
  6-128. Some other forms of CARP drop zones are random approach, area, and cicular drop zones. The
  GUC may also choose to place the point of impact randomly to better serve the mission.