An ambush is a short and rapid attack on an enemy force that is moving or at a short stop. The goal of organizing it can be: capturing a prisoner, capturing documents, capturing new enemy weaponry or equipment, inflicting losses and creating a decline in enemy morale.
Place of an ambush is chosen to provide the most cover and concealment possible and a concealed retreat route.
The tactic I’ll describe below is more akin to a special forces ambush than one carried out by regular infantry units. The reason is simple. In Arma or other mil-sims we rarely have the opportunity to conduct a platoon ambush.

Planning

Planning an ambush will mean planning what, when and where will be ambushed and by who with what. The most important is to pick a good place. It should allow for the ambushing force to have enough concealment to not alert the enemy before they walk into the kill zone and enough concealment to retreat safely after the ambush. For that reason the element’s leader should look for forested or built up areas on the route. Terrain features allowing for better cover and field of view are also welcome.

Formation

An ambush will consist of three main elements:

• security – responsible for securing the flanks and spotting the enemy force,
• weapons – responsible for creating a base of fire,
• assault – responsible for assaulting the kill zone.

Security elements can be constructed in two ways. They will either  contain a lot of firepower and be equipped with SAWs and GLs or will focus on accurate fires on range and will use a designated marksman. A lot of the time in Arma we can't spare the heavy guns from the kill zone and the marksmen will not be as effective at the shorter engagement ranges of an ambush.

The base of fire element will contain any MGs we can use and possibly AT specialists if we are ambushing a motorized enemy. Additionally the element leader might consider letting the weapons section control any explosives used for the ambush by attaching an explosives specialist to it.

The assault element will help create interlocking field of fire in the first stage of the ambush and then will move to clear out the kill zone and the area past it.

Additional elements can be assigned. A collections element may be assigned with clearing the kill zone by dragging bodies off the route and searching for documents/equipment. And a medic or a medical section may be created or assigned to a CCP to treat wounded. In Arma while there usually is a medic, there usually isn’t enough people to create a collection section. So the task falls to the assault element.

Element leader is responsible for selecting positions for all the sections unless they decide to delegate that responsibility to section leaders. They set the location of the kill zone (an area where the enemy force will be contained and destroyed) and coordinate the work of the element during the ambush.

Execution

Positions are taken by the sections. First the security section. Then the weapons section and last by the assault element.

The ambush starts by the security element spotting the main enemy force. It is crucial to not attack a scout section or vehicle instead of the main force. The security element relays that and any information about the enemy:

• quantity of enemy,
• quantity and type of vehicles,
• any special equipment,
• anything else that might influence an ambush.

Until the ambush initiates it is very important to stay hidden. When the enemy element gets is in the kill zone, the ambush initiates. The ambush is always initiated by the most casualty producing weapon. The best systems to start an ambush with are, in that order:

1. explosives (IEDs, claymores, mines etc.),
2. AT launchers if the element is mounted,
3. machineguns

Once the designated weapon fires, the ambush begins and both the weapons and assault elements open fire. There is no set amount of time for this part of the ambush. The goal of it is to suppress the enemy in place and inflict as many losses as possible. Once the element leader is happy with the result they will signal to cease fire and assault. Some phrases to expect might be: “Cease fire”, “Lift fire”, “Walk through”. Additionally if the kill zone is divided up into fire zones there might be a call to “Shift fire”.

When a command is given and the fire into the kill zone stops, the assault element walks through and clears the kill zone and a patch of land around 35 meters past the road/path (app. hand grenade range).

Once the walkthrough is complete and the objective completed all of the sections retreat to the predesignated RP. The retreat order is opposite to the order of taking positions. First elements retreat the last. So the assault element leaves followed by the weapons section and the rear is brought up by the security element.

Once at the RP the ambush is complete and the element can continue to the next task.

Ambush shapes

There are two main ambush shapes. Line and L-shaped. They are pretty self-explanatory. In a line ambush both the weapons and assault elements are set up along the route in a somewhat straight line. While an L-shape has the weapons section or part of it set up on a road bend, a barricade or something similar looking at the front of the enemy force. The shape should be chosen accordingly to the terrain but it is important to remember that we are still trying to achieve interlocking fields of fire when possible.