text: Chapter 1
  * Identification criteria. The employment of ADA weapon systems requires early identification of
  friendly, neutral, or hostile aircraft and missiles to maximize extended-range engagements and
  avoid fratricide. The problem of distinguishing friendly, neutral, and hostile aerial objects, while
  employing various weapon systems against the enemy, is a highly complex task; the same type of
  aircraft may be flown by friendly and enemy countries. The area air defense commander and the
  airspace control authority establish measures and procedures within the airspace control system to
  positively identify all airborne assets and permit the execution of AMD operations. These
  measures and procedures reduce delays in operations and prevent fratricide. Positive identification
  of tracks is normally the preferred method of operation. Positive identification is an identification
  derived from observation and analysis of target characteristics including visual recognition,
  electronic support systems, non-cooperative target recognition techniques, identification friend or
  foe systems, or other physics-based identification techniques (JP 3-01). Procedural identification
  separates airspace users by geography, altitude, heading, time, and/or maneuver. Generally, some
  combination of positive and procedural identification is used.
  * Fire control orders. Fire control orders are commands that are used to exercise control over
  engagements on a case-by-case basis and can be transmitted electronically or verbally. They are
  given to direct or inhibit firing by surface-to-air weapons units based on the ROE and rapidly
  changing tactical situation (JP 3-01). There are three primary orders: engage, hold fire, and cease
  engagement or cease fire. Engage in air and missile defense, a fire control order used to direct or
  authorize units and/or weapon systems to attack a designated target (JP 3-01). Hold fire is an
  emergency fire control order used to stop firing. If technically possible, missiles already in flight
  must be prevented from intercepting (JP 3-01). Hold fire is primarily used to effect friendly
  protection or avoid intercepts on neutral tracks. Cease engagement or cease fire directs units to
  stop the firing sequence against a designated target; however, units may continue to track, and
  missiles already in flight are permitted to continue to intercept (JP 3-01). Cease fire is normally
  issued to preclude engagement of the same track by two or more weapon systems.
  * Weapons control status. A weapons control status is an air and missile defense control measure
  declared for a particular area and time by an area air defense commander, or delegated subordinate
  commander, based on the rules of engagement that establish conditions under which fighters and
  surface air defense weapons are permitted to engage threats (JP 3-01). Weapon control statuses
  (weapons hold, weapons tight, and weapons free) prescribe the relative control of AMD fires.
  Weapons hold is the most restrictive status; units may fire only in self-defense or when ordered
  by a proper higher authority. Weapons tight is the normal status; units may only fire on targets
  identified as hostile in accordance with current ROE. Weapons free is the least restrictive status;
  it is used to indicate when any target not positively identified as friendly, in accordance with the
  current ROE [and law of armed conflict], may be engaged (JP 3-01).
  * Levels of control. Levels of control describe the AMD commander/echelon permitted to authorize
  engagement of an air or missile threat (JP 3-01). Engagement authorization is normally vested
  with the area air defense commander at theater level and can be delegated to as low as an ADA
  team leader when the mission and threat environment demands such. Different levels of control
  may be established for ballistic missiles, cruise missiles, UASs, fixed-wing aircraft, and rotary-
  wing aircraft.
  MODES OF CONTROL
  There are three modes of control: centralized, decentralized, and autonomous. In the centralized mode,
  a higher echelon must authorize target engagements by the firing units (positive control). In decentralized, a
  higher echelon monitors unit actions, making direct target assignments on a management-by-exception basis.
  The authority to which decentralization is authorized makes decisions based upon ROE (procedural control).
  Autonomous operations are initiated when a firing unit has lost all communications (voice, data link, and
  tactical chat) to higher headquarters. The fire unit makes decisions based upon the latest published ROE
  (procedural control). The mode of control selected will depend upon the capabilities of the C2 system and
  weapons employed and both the friendly and enemy air situations.