text: Chapter 6
  ARMY VIRS AND GMRS DROP ZONES
  6-30. For the verbally initiated release system (VIRS) and for the ground-marked release system
  (GMRS), allow a minimum size of 300 yards by 300 yards (275 meters by 275 meters). To determine the
  required size of Army VIRS DZs, use the D=RT formula (Figure 6-2). For personnel jumps, allow a
  100-meter buffer zone at the leading and trail edges of the DZ. If local regulations permit, the local
  commander can waive these buffer zones.
  Figure 6-2. Example application of D=RT formula.