text: Chapter 3
  DANGER
  Arriving and departing aircraft with slingloaded cargo must never
  fly over personnel, equipment, or other aircraft.
  SECTION III. GROUND-TO-AIR COMMUNICATIONS
  Air traffic control requires a rapid and efficient means of communication between aircraft and ground stations.
  Two-way radio offers the most efficient means because it allows clear and rapid exchange of information. Not
  all aircraft have radios that work. A system of visual signals serves as a backup or standby means of
  communication when the control center or aircraft radio does not work, or if the aircraft does not have the
  control frequency (Table 3-6). Pathfinders might also use colored smoke signals but must coordinate with the
  aviation unit so that the pilots will know what each color means.
  ELECTRONIC WARFARE ENVIRONMENT
  3-46. The pathfinder should expect an active EW environment for all operations. He should make sure
  he knows the proper ECCM. These include prowords that signal a switch to an alternate radio frequency,
  transmission authentication procedures, brevity codes, and required reports when he suspects enemy
  interference. The pathfinder uses proper communications procedures and signal operating instructions
  (SOI) during all operations.
  3-47. To limit the possibility of compromise, the pathfinder reduces the electronic signature at the LZ or
  DZ. For this, he depends on thorough mission planning and coordination. He plans control procedures that
  enable him to execute the mission under radio listening silence. All pathfinder missions seek to achieve
  this goal.
  3-48. Sometimes, the pathfinder has little time to plan the mission. At other times, tactical or
  meteorological conditions can affect the operation. In either case, the pathfinder might have to use GTA
  communications to resolve possible conflicts between friendly airspace users and to advise them of
  previously-unknown restrictive landing conditions. These conditions could include wind gusts, hazardous
  slopes, obstacles, soft landing surfaces, or a limited number of landing points. Training and close liaison
  with aviation aircrews enable the pathfinder to develop an understanding of what information pertains to
  the situation. This reduces transmission time.
  3-49. The pathfinder manages any variation due to unknown influences just as he would manage any
  other exception to set procedure. The landing site is the variable most subject to change. Many conditions
  could require its relocation. For example, ground fog could cause a delay while the pathfinders move the
  site to a higher elevation.
  3-50. Before they know whether a site will support sufficient landing points or an assembly area for the
  ground unit, the pathfinders must first secure the site, and then conduct air and ground reconnaissance and
  surveillance.
  3-51. If the mission is to reinforce or resupply a ground unit in contact, a change in the tactical situation
  could render the proposed location unsuitable. If the pathfinders locate the proposed site near enemy
  activity, they will most likely have to move it sometime between planning and execution to ensure that it
  continues to meet mission requirements.
  3-52. Maintaining radio silence within the LZ is important. Because of this, most air movements require
  the establishment of a CCP. This ensures a common point where the pathfinders and the aircraft can refer
  their relative positions and give each other time to adjust to other changes.
  3-53. The GTA net is reserved for communications, but the pathfinder cannot assume that all
  transmissions originate from aircraft. The headquarters in charge of flight plans logs all arrivals. They will