text: Chapter 4
  PHYSICAL DAMAGE
  4-209. Physical damage to a tunnel entrance generally makes it impassable and can reduce the
  protection afforded to anything or anyone in the tunnel during follow-on attacks.
  No Damage--Military action has caused no apparent damage.
  Light Damage--Military action has left the portal (the approach or entrance to the tunnel) intact,
  but craters and debris partly block access. The doors, if any, operate as before the attack.
  Moderate Damage--Military action has left the portal intact, but entrance to the tunnel is
  completely cut off by craters or debris. The doors, if any, do not operate.
  Severe Damage--Military action has partly collapsed the portal, and has completely blocked any
  entrance to the tunnel.
  Destruction--Military action has completely collapsed the portal, rendering access to the tunnel
  impossible.
  FUNCTIONAL DAMAGE
  4-210. The extent of functional damage depends on the size of crater(s), the degree of portal collapse,
  or the amount of debris blocking the entrance. Degree of functional damage also depends on the purpose
  of the tunnel facility. For example, a storage tunnel is much more vulnerable to entrance damage than a
  C2 tunnel, which depends less on ingress and egress. The time required to repair tunnel entrances
  depends on the extent of damage and the availability of personnel and equipment. In addition, the tunnel
  might have many entrances. How many it has affects the level of functional damage. When reporting the
  functional damage to tunnel entrances, the team considers accessibility based on how many entrances
  remain useable.
  TUNNEL FACILITY AIR VENTS
  4-211. Air vents are vital for some tunnel facilities. They bring in fresh air and remove exhaust fumes
  and other noxious byproducts. Closing off these vents can sometimes prevent usage of the tunnel or
  facility altogether. The vents are less critical for facilities used for storage only, but more critical if they
  contain operating equipment and people.
  PHYSICAL DAMAGE
  No Damage--Military action has caused no apparent damage.
  Damage--Military action has partly blocked the vent opening with craters and debris. The vent
  structure might not be damaged.
  Destruction--Craters or debris completely block the vent opening.
  FUNCTIONAL DAMAGE
  4-212. Functional damage restricts or cuts off airflow through the vent(s) in the facility. Complete
  elimination of airflow to or through the facility might require the destruction of multiple air vents. When
  reporting the functional damage of the facility vents, the team must divide the number of damaged vents
  by the total number of vents to determine the overall percentage of airflow blockage in the facility.
  Section V. TARGET ACQUISITION
  Target acquisition is conducted by a combat patrol. The intent of a combat patrol is to make contact with the
  enemy, in contrast to a reconnaissance patrol where the intent is to avoid enemy contact. LRS teams seldom
  conduct combat patrols. However, the capability to conduct a target-acquisition mission is inherent within a
  LRS team. The team can serve as the initial eyes of a long-range targeting asset, by providing terminal guidance
  using appropriate communication and signal such as a beacon or mirror by marking the target with a laser.
  Normally, a LRS team is tasked to conduct surveillance or reconnaissance of an NAI. If a target of opportunity