text: Helicopter Landing Zones
  the visual aids displayed. You can use arm-and-hand signals to help control the landing, hovering, and
  parking of helicopters.
  AIR CONTROL POINTS
  4-56. Pathfinders might have to manage air control points (ACPs) to help aircraft en route to the LZ.
  ACP PARTY RESPONSIBILITIES
  4-57. The ACP party consists of two or three pathfinders, or at least one pathfinder and assistants. The
  party positions and operates electronic navigation aids, visual navigation aids, or both. The party also
  operates radios in the pathfinder internal net (if used) and the GTA net. The ACP party monitors the GTA
  net so they can respond at once to any pilot's request for help finding an ACP.
  NAVIGATION AID ORDER
  4-58. The ACP party installs navigation aids as soon as it arrives at the site or as planned. They try to set
  up all of the aids at the same time. However, if they cannot do this because they have too few people, or for
  some other reason, then they set them up in the following order:
  GTA Radio
  4-59. The party sets this up first. Then, if the aviation unit commander has asked them to do so, they
  install the electronic homing beacon. This beacon allows the party to offer long-range guidance. If they do
  use the beacon, the party sets it up far enough away to prevent excessive radio interference. This also helps
  keep the enemy from destroying the radios and the beacon at the same time.
  Visual Navigation Aids
  4-60. These navigation aids vary in number and type, depending on aviation unit SOPs and requirements
  and on the need for security. The ACP party removes any grass or brush that masks their usage of these
  aids, but they also plan a way to conceal the markings in case they sight enemy aircraft.
  Internal Net Recorder
  4-61. The pathfinder internal net recorder sets up communications with the landing zone CCs as fast as
  he can. He immediately reports the state of ACP readiness and any information about the local enemy
  situation, if any. Unless directed to operate a beacon on a definite time schedule, he constantly monitors
  the radio.
  Security Personnel
  4-62. The ACP party can include attached personnel from the supported units. These personnel provide
  security. They both move to their assigned locations and take up security positions, or they help set up and
  operate navigation aids and communications equipment.
  SECTION V. NIGHT OPERATIONS
  Daytime visual references (checkpoints for positive identification) are difficult to see at night. Visual aids for
  night navigation emit illumination. Having too few visual references can cause pilots to concentrate on a single
  light or group of lights in a concentrated area. This can cause visual illusions, which can then cause vertigo. To
  prevent this hazardous situation, pathfinders mark LZs with multiple lights and mark landing areas with two or
  more widely separated lights.