text: Chapter 5
  (cid:122) Terrain. Flat or rollingterrain isdesirable;it should be relatively free, but notnecessarilyclear,
  of obstacles. Obstacles on a drop zone do not prevent paratroopers from landing but increase
  jumpcasualties.Sites in mountainousorhilly countrywithlargevalleysorlevelplateaus canbe
  used forsecurityreasons.Smallvalleysorpocketscompletelysurroundedbyhillsaredifficultto
  locateand shouldbeused onlyinrarecases.Commanders mustavoid man-made obstaclesmore
  than150feet(46meters)above thelevelofthe dropzone withinaradius ofthreenauticalmiles.
  High ground or hills need not be considered a hazard unless the hills pose an escape problem
  that is beyond the aircraft’s capability. High ground or hills more than 1000 feet (305 meters)
  above the surface of the site should not be closer than three nautical miles to the drop zone for
  night operations. The perimeter of the drop zone should have one or more open approach areas
  freeofobstaclesthatwouldpreventtheaircrew’ssightingofthe dropzonemarkings.
  Coverandconcealment. Coverandconcealment near the dropzones or landingzonesare a
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  distinctadvantagewhentheairborneforcesassembleandwhenairlandforcesland.
  Road network. Having a drop zone near a good road networkexpedites moving personnel,
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  supplies, and equipment from that zone. If the landing area contains terrain that is to be
  developed into an air landing facility, a road network is of particular value not only for
  moving items from the facility but also for evacuating personnel and equipment as well.
  However, a road network offers the enemy a high-speed avenue of approach and must be
  defended.
  Keyterrain. The drop zone site selected should aid in the success of the mission by taking
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  advantage of dominating terrain, covered routes of approach to the objective, and terrain
  favorablefordefenseagainstarmoredattack.
  5-27. Minimum construction for drop zones or landing zones. Because of limited engineer support in the
  airborne force, selected landing zones should have a minimum requirement for construction and
  maintenance. Unless more engineer support is requested and received, construction and maintenance
  restraintscanlimitthenumberofareasthatcanbeusedordeveloped.
  5-28. Mutual support. Commanders should select mutually supporting drop zones or landing zones that
  provideinitialpositionsfavorabletotheattack.
  5-29. Configuration. The division or brigade commander gives guidance on drop size in operations plans
  oroperationsorders.Theneachunitcommanderdeterminestheexactshape,size,andcapacityrequired.
  (cid:122) Shape. The most desirable shapes for drop zones are rectangles or circles; these permit a wider
  choice of aircraft approach directions. However, they require precise navigation and timing to
  avoidcollisionsordropinterference.
  (cid:122) Size. The drop zone should be large enough to accommodate the airborne force employed; one
  dropzonethatallowstheaircraft todrop its entireloadinonepassisdesirable.Repeatedpasses
  are dangerous because the initial pass can alert enemy antiaircraft and other emplacements,
  waitingforsubsequentdrops.
  There are certain situations, however, when multiple passes are used. This occurs mainly
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  whenthere isno significant air defense threat and orbits are made over areas where enemy
  antiaircraft systems are not positioned. This applies especially to the seizure of islands
  where small drop zones are the rule. If there are enough aircraft available to deliver the
  force with fewer personnel oneach aircraft, there is no realproblem. However, ifthere are
  onlyenoughaircrafttodeliver the assaultecheloninone lift witheachaircraftcarryingthe
  maximum number of personnel, then the aircraft has to make multiple passes over the
  dropzone.
  A large drop zone can permit several points of impact to be designated and used. It is
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  desirabletosaturate theobjectiveareaintheshortestpossibletimebutthereis areasonable
  limitto the amountofpersonnel and heavyequipment drop thatcanbe stacked on a single
  drop zone. Therefore, it can be desirable to use multiple points of impact on a single drop
  zoneprovidedthedropzoneislargeenoughtopermitthis.
  (cid:122) Capacity. The drop zone capacityis based on the expected number of forces to be dropped and
  theirdispersionpattern.