text: Chapter 4
  4-31. Security operations are those operations undertaken by a commander to provide early and accurate
  warning of enemy operations, to provide the force being protected with time and maneuver space within
  which to react to the enemy, and to develop the situation to allow the commander to effectively use the
  protected force (ADRP 3-90). Reconnaissance is a mission undertaken to obtain, byvisual observation or
  other detection methods, information about the activities and resources of an enemy or adversary, or to
  secure data concerning the meteorological, hydrographic, or geographic characteristics of a particular
  area(JP 2-0).
  4-32. After the force makes the initial assault landing and accomplishes its first missions, the commander
  organizes theairheadlineasthedefenseperimeter.The terrainand situation dictates howunitsoccupyand
  organizetheairheadline.Forcesassignedreconnaissanceandsecuritytasks,usuallyincludereinforcingthe
  security area. The mission, enemy capabilities, and defensive characteristics of the terrain determine the
  degree to whichtheairheadlineisactuallyoccupiedand security areaforcesare organizedfortheairhead.
  Task organization of security and reconnaissance forces is METT-TC-dependent and may include scouts,
  Infantry, cavalry, antitank weapons, engineers, Army aviation, electronic warfare, and follow-on Stryker
  andArmoredforces.
  SecurityForces
  4-33. Security forces land early in the assault echelon. In the early stages of an airborne operation, the
  security force acts as a screening force. In later stages (when assault missions have been accomplished,
  when the airhead is relatively secure, and when more forces are available), it acts as a guard force. The
  security area is established four to six kilometers from the airhead line to afford security to the airborne
  force during its landing and reorganization. Security forces come under BCT control except during short
  missions such as raids, when they come under battalion or squadron control. The mission of the security
  forceisto—
  (cid:122) Givetheairheadearlywarning.
  (cid:122) Developinformationcollection,toincludethelocation,direction,andspeedofanenemyattack.
  (cid:122) Denytheenemyobservationofandabilitytodirectindirectfireontheairhead.
  (cid:122) Deceivetheenemyastotheactuallocationoftheairhead.
  (cid:122) Delayanddisrupttheenemy.
  4-34. The need for and positioning of additional security forces is determined by the next subordinate
  commander.Whenpossible, mobile forces are selected to facilitaterapid initial movementto positionsand
  to facilitate withdrawal and adjustment. An aggressive reconnaissance and surveillance effort at lower
  echelons augments the security force. The following considerations apply to the selection of positions for
  thesecurityforce:
  (cid:122) Locate them within radio communications and fire support range. However, this range can be
  extended, if necessary, with retransmission stations, split section indirect-fire operations, and
  attachmentofvehicles,mortars,orotherassetstothesecurityforce.
  (cid:122) Locate them as roadblocks, obstacles, ambushes, patrols, or sensors (depending on the enemy)
  on dominant terrain. This allows long-range observation and fields of fire out to the maximum
  rangeofsupportingfires.
  (cid:122) Locatethemtoobserve,control,anddominateenemyhigh-speedavenuesofapproach.
  (cid:122) Locatethemtodenyenemylong-rangeobservationandobserved indirectfireintotheairhead.
  (cid:122) Locatethemfarenoughouttoprovideearlywarning.
  (cid:122) Locate themto provide routesof withdrawalto the airhead. Observationposts generallyrelyon
  theirabilitytohideastheir mainprotection;they canallowthe enemytopasstheir positionand
  notwithdraw.
  ReconnaissanceForces
  4-35. Designated forces under control of the ABNAFC perform reconnaissance missions within the
  security area; emphasis is placed on likely enemy avenues of approach. The mission of these forces is to
  gain and maintain contact withenemy units reactingto the airborne assault. This force is mobile and not