MCRP 12-10B.1, page 129

Figure 4-1. Helicopterborne Assault of a Built-Up Area f. Combat Roles. Below are some of the roles that assault support helicopters may play in urban warfare: Conduct insertion and extraction of forces (See MCRP 3-11.7A, Helicopter insertions and Extractions [under development]) Provide command/control and aerial retransmission Support CSS operations Provide air reconnaissance. 4203. Employment of Reconnaissance Forces. Reconnaissance units traditionally make maximum use of rural camouflage and terrain. Area, zone, and route reconnaissance are conducted from well-concealed vantage points through clandestine insertion by foot, vehicle, rubber boat, or helicopter. These methods of insertion may still apply in village and strip areas for collection of information, sensor employment, conducting OP radio relays, or a combination of missions. In major urban areas, undetected insertions are difficult to accomplish because of the high density civilian population. MCWP 3-35 .3 4-16