text: Chapter 4
  y Visibility (day/night).
  y Type of mission (insertion, extraction, resupply, slingload drop-off, forward area arming and
  refuel point [FAARP], and so forth).
  Figure 4-1. Landing point sizes.
  4-5. Standard landing point uses and types of aircraft are listed in Table 4-1. Standard landing point
  sizes are listed in Table 4-1.
  4-6. In a landing site, pathfinders measure the minimum distances between landing points, from center
  to center. When aircraft sizes vary, pathfinders separate landing points by the most generous measure,
  allowing 100 meters for size 5; 125 meters for size 6; 150 meters for size 7, measured center to center on
  the landing points.
  4-7. The aviation unit commander, during coordination, might have authorized pathfinders to reduce the
  TDP by one size. Reducing TDP is a last-resort means to make an HLZ suitable to accomplish the mission.
  TDP sizes are reduced in a deliberate manner after careful consideration of all factors. If mixed aircraft
  types will use the TDP, the size should be reduced for utility (lighter) aircraft before slingload aircraft.