Infantry Drills

FM 3-21.8 – Chapter 4 – Section II – Air and Missile Defense

Section II – Air and Missile Defense

4-35.     Leaders must consider the use of air defense (AD) if evidence exists of enemy forces having the ability to employ fixed- or rotary-winged aircraft, or unmanned aircraft systems (UAS) against friendly forces. Operations in these situations require forces to be thoroughly trained on passive and active AD measures.

4-36.     AD assets such as Stingers and Avengers may operate in and around the unit’s AO, but the AD is not likely to be task-organized specifically to the Infantry platoon or squad. Therefore, the Infantry platoon and squad must conduct its own AD operations, relying on disciplined passive AD measures and the ability to actively engage aerial platforms with organic weapons systems.

Early Warning Procedures

4-37.     Local AD warnings describe with certainty the air threat for a specific part of the battlefield. Air defense artillery (ADA) units use these local warnings to alert units to the state of the air threat in terms of “right here, right now.” There are three local AD warning levels:

– Dynamite. Enemy aircraft are inbound or are attacking locally now.

– Lookout. Enemy aircraft are in the area of interest but are not threatening. They may be inbound, but there is time to react.

– Snowman. Enemy aircraft do not pose a threat at this time.


NOTE:  The area ADA unit commander routinely issues AD warnings for dissemination throughout the theater of operations. These warnings describe the general state of the probable air threat and apply to the entire area.

Passive air defense

4-38.     Passive AD is the Infantry platoon and squad’s primary method for avoiding enemy air attack. Passive AD consists of all measures taken to prevent the enemy from detecting or locating the unit, to minimize the target acquisition capability of enemy aircraft, and to limit damage to the unit if it comes under air attack. Target detection and acquisition are difficult for crews of high-performance aircraft, and the unit can exploit this advantage.


4-39.     The Infantry platoon and squad should follow these guidelines to avoid detection or limit damage if detected:

– When stopped, occupy positions that offer cover and concealment and dig in and camouflage.

– When moving, use covered and concealed routes.

– Disperse as much as possible to make detection and attack more difficult.

– Eliminate or cover the spoil from dug-in positions.

– Do not fire on a hostile fixed-wing aircraft unless it is clear that the aircraft has identified friendly elements. Premature engagement compromises friendly positions.

– Designate air guards for every position; establish and maintain 360-degree security.

– Establish an air warning system in the unit SOP, including both visual and audible signals.


4-40.     When the Infantry platoon or squad observes enemy fixed-wing aircraft, helicopters, or unmanned aircraft systems (UAS) that could influence its mission, it initially takes passive AD measures unless the situation requires immediate active measures. Passive AD measures normally mean that friendly unit initiates its react-to-air-attack battle drill; however, the leader can initiate specific passive measures if necessary.

4-41.     Passive AD involves these three steps:

– Step 1. Alert the friendly unit with a contact report.

– Step 2. Deploy or take the appropriate actions. If the Infantry platoon or squad is not in the direct path of an attacking aircraft, leaders have all friendly Soldiers seek cover and concealment and halt with as much dispersion as possible based on the terrain.

– Step 3. Prepare to engage the enemy aircraft.

Active air defense

4-42.     Infantry platoons and squads avoid engaging enemy aircraft. If engagement is unavoidable, the friendly unit uses a technique known as volume of fire. This technique is based on the premise that the more bullets a unit can put in the sky, the greater the chance the enemy aircraft will fly into them. Even if these fires do not hit the enemy, a “wall of lead” in the sky can intimidate enemy pilots. This can cause them to break off their attack or distract them from taking proper aim. One of the most important points about volume of fire is that once the lead distance is estimated, Soldiers must aim at the estimated aiming point and fire at that single point until the aircraft has flown past it. Soldiers maintain the aiming point, not the lead distance. Once a Soldier starts firing, he does not adjust his weapon. Leaders establish the aiming point based on the type of aircraft that is attacking (Figure 4-2).


Figure 4-2. Volume of fire aim points.

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