FM-3-09 Fire Support and Field Artillery Operations Download
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Environmental and Terrain Considerations for Fire Support 30 April 2020 FM 3-09 D-5 The presence of large expanses of polished, flat, highly reflective surfaces such as windows may reflect laser energy and pose a hazard to friendly troops. The presence of highly absorptive surfaces such as open windows or tunnels may degrade designator effectiveness. Because of a fluid forward line of own troops, designators may have to reposition more often. Weather effects on the employment of laser designators and range finders. D-27. The mix of munitions used by indirect fire systems will change somewhat in urban areas. Supporting unit commanders rely on their FSCOORDs to understand ammunition effects and to correctly estimate the number of volleys needed for the specific target coverage. Increased use of certain munitions (for example Excalibur and other HE or smoke rounds, and precision guidance kit, delay and concrete-piercing fuzes) should be anticipated. D-28. Special considerations apply to shell and fuze combinations when buildings limit effects of munitions: Indirect fires may create unwanted rubble and collateral damage. Precision and precision-guided munitions can be used to minimize rubbling. The close proximity of enemy and friendly troops requires careful coordination of fires. Swirling winds may degrade smoke operations. White phosphorus may create unwanted fires and smoke. Fuze delay should be used to penetrate fortifications or tops of buildings. Point detonating fuzes on delay typically penetrate only the first wall or roof of a structure. The MK 399 concrete piercing fuze is used when added penetration is necessary. Use of visible illumination may favor the defender who lacks night vision devices. Illumination rounds can be effective; however, friendly positions should remain in shadows, and enemy positions should be highlighted. Tall buildings may mask the effects of illumination rounds. Illumination rounds fired to burn on the ground or on a building can also be used to mark targets for aerial support. Airbursts (variable time or time fuze) and improved conventional munitions are effective for clearing those antennas and enemy observers located on rooftops and for suppressing enemy fires. Variable time fuzes may detonate prematurely due to the proximity of other structures. Observer-adjusted time fuzes may be better to use among buildings with varying heights. If the area will be crossed by friendly or civilian personnel, units may choose not to use improved conventional munitions due to the dud munitions hazard or if the enemy has several building floors for overhead protection. Scatterable mine effectiveness is reduced when delivered on a hard surface. DIRECT FIRE D-29. Artillery may be used in the direct fire mode. Commanders, in consultation with their FSCOORD and FSEs, determine the parameters under which FA assets can be used as direct fire platforms. Normally, FA is employed in direct fire only where tanks, Bradley fighting vehicles, and other direct fire systems are not available to engage the target. In this case, subordinate and supporting unit commanders, in coordination with their respective FSCOORD and fires cell planners, direct the employment of individual howitzer sections to support the unit in contact. Commanders should identify their most proficient direct fire sections. D-30. Self-propelled systems can take advantage of the systems' mobility to support multiple maneuver elements. FA used for direct fire will likely require shuttling between indirect fire and direct fire positions. One or more sections may need to follow a maneuver force closely if sustained direct FS is needed. Self- propelled howitzers are effective in neutralizing or destroying bunkers, heavy fortifications, or enemy positions in reinforced concrete buildings. Concrete-piercing 155-mm rounds can penetrate 36 inches of concrete at ranges up to 2,200 m. If care is taken, self-propelled artillery can be used to clear or create avenues of approach. Due to the self-propelled howitzer's limited armor protection, infantry will be required to provide security from enemy snipers and antitank teams.