--Additional Planning Considerations


2-47. Additional offensive planning considerations include urban terrain, air assault operations, and operations in mountainous terrain.

Air Assault Operations

2-48. Air assaults are high-risk, high-payoff missions. When properly planned and vigorously executed, these missions allow leaders to generate combat power and apply warfighting functions. An air assault can provide leadership the means to control the tempo of operations, enabling rapid execution of operations to retain or exploit the initiative.

2-49. An air assault task force is most effective in environments where limited lines of communications are available to the enemy, who also lacks air superiority and effective air defense systems. It should not be employed in roles requiring deliberate operations over an extended period, and is best employed in situations providing a calculated advantage due to surprise, terrain, threat, or mobility. In particular, an air assault task force is employed in missions requiring -

  • Massing or shifting combat power quickly.
  • Using surprise.
  • Using flexibility, mobility, and speed.
  • Gaining and maintaining the initiative.

2-50. FM 3-99 addresses the following basic considerations for planning and execution of air assaults -

  • Air assault operations are best conducted at night or during weather conditions allowing aircraft operations that obscure enemy observation. This facilitates deception and surprise.
  • Indirect fire support planning provides suppressive fires along air routes and in the vicinity of landing zones. Priority for fires should be to the suppression of enemy air defense systems.
  • Infantry unit operations are not changed fundamentally by integrating with aviation units. However, tempo and distance are changed dramatically.
  • Ground and aerial reconnaissance units should be employed as early as possible to conduct reconnaissance and surveillance activities in order to shape the operational area for execution.

Urban Terrain

2-51. Offensive tasks in urban terrain are designed to impose the leader’s will on the enemy. Offensive missions in an urban environment aim to destroy, defeat, or neutralize an enemy force. However, the purpose may be to achieve some effect relating to the population or infrastructure of the urban area. Leaders should use a combined arms approach for offensive urban operations.

2-52. Offensive missions in urban areas are based on offensive doctrine applied to urban terrain. Urban terrain imposes a number of demands different from ordinary field conditions, such as problems with troop requirements, maneuver, and use of equipment. As with all offensive missions, the leader must retain his ability to maneuver against enemy positions. (Refer to ATTP 3-06.11 for more information.)

Subterranean Environments

2-53. In cities, subterranean features include underground garages, passages, subway lines, utility tunnels, sewers, and storm drains. Most allow troop movement. In smaller towns, sewers and storm drains may permit Soldiers to move beneath the fighting to surface behind the enemy. Knowledge of nature and location of underground facilities is of great value to both the urban attacker and defender. Subterranean routes can grant attackers use of both surface and subterranean avenues of approach, enabling them to place a smaller force behind enemy defenses. Depending upon strength and depth of the aboveground defense, attackers along the subterranean avenue of approach can become the main attack. If subterranean efforts are not immediately successful, it forces defenders to fight on two levels and to extend his resources to more than just street-level fighting. (Refer to ATTP 3-06.11 for more information).

2-54. The presence of subterranean passages forces defenders to cover urban areas above and below ground with observation and fire. Subterranean passages are more a disadvantage to defenders than the attackers are. However, given the confining, dark environment of these passages, they do offer some advantages when thoroughly reconnoitered and controlled by the defender. A small group of determined Soldiers in a prepared defensive position can defeat a numerically superior force. Subterranean passages —

  • Provide covered and concealed routes to move reinforcements or to launch counterattacks.
  • Can be used as lines of communications, for movement of supplies, evacuation of casualties, and to cache supplies for forward companies.
  • Offer defenders a ready-made conduit for communications wire, protecting it from tracked vehicles and indirect fires.
  • Afford attackers little cover and concealment other than darkness and any man-made barriers.


Engineers burn through a steel door during subterranean training.

Engineers burn through a steel door during subterranean training.



Operations in Mountainous Terrain

2-55. Combat in mountainous areas present units with complicated hazards, difficulties, opportunities, and risks. Mountainous combat operations call for high levels of physical fitness, mental toughness, endurance, and tactical and technical proficiency on the part of all individuals.

2-56. A disciplined and prepared Infantry platoon and squad is task-organized with and supported by other members of the combined arms team, which are crucial to small-unit mountain operations. Units fighting in mountainous areas, overcome difficulties, measures risks, and exploit opportunities to close with and defeat the enemy. Prepared leaders anticipate, understand, and adapt to physical demands of mountainous environments. They face and overcome challenges of fighting in areas where technological supremacy can be negated by crude and nontechnical enemy actions. Unit leaders who know what to expect during mountainous operations create situations allowing their units to adapt to challenges and achieve victory in all environments.

2-57. Infantry units conducting operations in mountainous terrain are able to adapt and skillfully use environmental challenges to their advantage. (Refer to ATTP 3-21.50 for more information). The landscape and climatic conditions create a unique set of mountainous operations characterized by -

  • Close fights with dismounted Infantry. Mountainous combat often is close in nature as opposing forces meet on rugged terrain. Though engaging targets near limits of direct fire weapons occurs in mountainous engagements, intervening crests, hills, ridges, gullies, depressions, and other terrain features often limit long-range battles with the enemy. Upper levels of mountainous terrain are characterized by lack of trafficable roads. Use of vehicles often is restricted, forcing dismounted operations.
  • Decentralized small unit operations. Conflicts in mountainous environments are often fought on platoon and squad level, as terrain commonly does not support movement and maneuver of large units. Compartmentalization of mountainous terrain can separate brigades from battalions, battalions from companies, and companies from platoons for long periods. As altitude increases in mountainous environments, terrain generally becomes more rugged and restrictive, which drives the need for decentralized execution of missions by dismounted platoons and squads.
  • Degraded mobility and increased movement times. Ruggedness of mountainous terrain often restricts mobility to foot movements using file-type formations on roads and trails. A relatively short distance from point to point may be an arduous movement over steep, rocky, uneven terrain with multiple trail switchbacks increasing distance traveled and tremendous energy expenditure.
  • Unique sustainment solutions. Sustainment in mountainous environments is challenging and time-consuming. Terrain and weather complicate virtually all sustainment operations including logistics resupply, medical evacuation, casualty evacuation, and Soldier health and hygiene. Network of restrictive mountainous roads often does not support resupply vehicles with large turning radius, or permit two-way traffic. Movement of supplies often involves a combination of movement types including air, vehicle, foot, and animal, with each technique having its own challenges in mountainous environments.
  • Operations in thinly populated areas. Populace in typical mountainous environments mostly live in small villages in valleys, with some scattered villages in upper mountainous areas. Although farmers and animal herders make up a large majority of the indigenous population and may work higher up in altitude, the vast majority of mountainous terrain remains unpopulated.

Tunnels and Caves

2-58. Tunnels, caves, and dry wells have historically been used for hiding places, food and weapons caches, headquarters complexes, protection against air strikes and artillery fire. Enemy personnel use these areas for both offensive and defensive actions. An extensive tunnel system containing rooms for storage and hiding as well as passages to interconnected fighting points may be encountered. Tunnels and caves are not only dangerous obstacles but can be an outstanding source of enemy information. Presence of a tunnel complex within or near an area of operations poses a continuing threat to all personnel in the area and no area containing tunnel complexes should ever be considered completely cleared.

2-59. Since tunnel complexes are carefully concealed and camouflaged, search and destroy operations should provide adequate time for thorough searches of an area to locate all tunnels and caves. Using of local nationals and host-nation scouts can be of great assistance in locating caves, tunnels, defensive positions, and likely ambush sites. Caves, trenches, spider holes, and tunnels are well incorporated into mountainous terrain and enemy operations and may be used as a deception to draw friendly forces into a cave or tunnel system rigged with booby traps or set with an ambush. (Refer to ATTP 3-21.50 for more information).

Soldiers clear a large cave system.

Soldiers clear a large cave system.

Edited by MAJ J.LaFlash