The AH-6 is a variant of the Littlebird helicopter designed to provide close air support with a variety of weapons. It is the smallest attack helicopter used and easily one of the most common.
The AH-6 is very maneuverable and agile, allowing it to dart around over friendly forces to attack enemies coming from multiple directions, while being difficult to hit with enemy anti-aircraft weapons. When the situation calms down, the AH-6 can scout ahead of friendly forces and perform interdiction, but will mostly stay above friendlies.
The AH-6 can carry a wide variety of weapons, including one or more Miniguns, GAU-19s, FFARs, and (rarely) DAGRs. The AH-6M (a modernized version of the aircraft, often seen in ArmA 3) has a powerful optic system that can be used by the copilot to accurately observe enemy movements from a distance.
Description and Design
The AH-6 was developed alongside the MH-6 in the 1960s as a light airborne weapons platform. The AH-6 (officially the A/MH-6, though other model names also exist) served mostly as support for special operations forces, which used the MH-6 for insertions and required an equally agile attack helicopter for close air support during their operations.
There are very few differences between the MH-6 and AH-6 - the airframe is almost identical. The shelves on either side of the MH-6 -- used on to seat passengers on the skids -- are replaced on the AH-6 with two stub wings with pylons that can fit a variety of weapons.
The removal of the shelves, as well as the inclusion of an ammunition compartment, effectively removes almost all space for passengers on the AH-6. An extra passenger (e.g. a fellow downed pilot) can sit on the left wing stub, but otherwise the AH-6 is not suitable for transporting troops.
Nevertheless, even when carrying a full load of weapons the AH-6 is still incredibly agile. It can quickly accelerate to its maximum speed (over 200 km/h), stop and change directions almost on a whim, and hug the terrain easily during low, fast flight. The AH-6 can use the terrain very effectively to hide itself from enemy fire until it is ready to attack.
AH-6M
The AH-6M is a modernized version of the AH-6, based on the "Mission Enhanced Little-Bird" (MELB) design.
The AH-6M has several notable differences from the original model. For one, changes in the modeling of Miniguns in ArmA 3 have made miniguns a less-favored weapon compared to the ArmA 2 era. However there is no direct alternative.
Additionally, the AH-6M can use the GAU-19 .50 caliber multi-barreled heavy machine gun to attack and destroy enemy light vehicles. Unfortunately, this weapon is difficult to use and is not often seen.
Finally, the AH-6M features the MELB's powerful nose-mounted camera. This camera can be used by the co-pilot (or anyone sitting in that seat). The camera has good stabilization and zoom, as well as several HUD features that make it easier for the co-pilot to keep oriented, as well as allow the pilot to know where the co-pilot is looking at any given time. This makes the AH-6M very good at spotting and observing enemy units from the air, so long as a co-pilot is present.
Weapons
As an Attack Helicopter, the AH-6 relies on its weapons to perform its role. Each AH-6 can carry weapons on up to 4 pylons on its stub wings. Most commonly, the AH-6 carries two pairs of identical weapon systems, with one of each pair on each wing (for example a minigun and FFAR pod on one wing, and a minigun and FFAR on the other). Identical weapons fire simultaneously with each trigger pull.
Different weapons allow the AH-6 to engage different types of targets. Most AH-6 weapons are designed for killing enemy infantry and lightly-armored vehicles.
The AH-6's initial weapon load-out is selected before the mission begins, based on the types of targets expected on the battlefield. An AH-6 may RTB to exchange its weapons for different ones, in case its weapons prove ineffective against the targets encountered on the battlefield, or in case different targets are expected to appear as the mission evolves.
M134 Minigun
The Minigun is a multi-barreled rotary machine gun firing 7.62mm bullets at an extremely high rate. It can shower a target area with hundreds of bullets within only a few seconds, practically ensuring a hit on any target within the strike area (called the "beaten zone"). A single minigun may have thousands of rounds available initially, and can burn through them very quickly if fired haphazardly.
With 7.62mm bullets, the minigun is particularly effective against enemy infantry and light vehicles (up to and including armored cars, which it can disable by hitting their wheels), but cannot penetrate any heavier armor.
Due to unspecified changes to the modeling of Miniguns in ArmA 3, their effectiveness seems to have dropped in this version of the game - increasing the use of FFARs and similar area-effect weapons over miniguns. They are still frequently featured on AH-6s nevertheless.
GAU-19
The GAU-19 is a multi-barreled rotary heavy machine gun firing .50 cal bullets at a high rate. Like the Minigun, the GAU-19 can discharge a large number of rounds within a very short timeframe. It carries far fewer rounds of ammunition than the Minigun, but each round is significantly more powerful on impact.
The .50 cal bullets of the GAU-19 are powerful enough to penetrate some armor, and can disable or destroy APCs and may even damage IFVs. However, the relatively-slower firing rate of this weapon makes it less likely to hit a target if not properly aimed, making this a difficult weapon to use. Despite its devastating effect on infantry, the GAU-19 is not likely to actually hit them, thus making it far less effective against infantry than the Minigun.
The weight of the GAU-19 means that only one will normally be installed on each wing. In missions featuring this weapon, the GAU-19 was usually mounted on a single wing while an FFAR rocket pod was mounted on the other wing.
FFAR
The FFAR (Fin-Folding Aerial Rocket) is a rocket pod firing 70mm unguided rockets. Each FFAR pod usually carries 19 rockets. Often, two such pods are installed on the aircraft (one on each wing), and both pods simultaneously fire a single rocket with each trigger pull.
FFARs are unguided rockets, firing forward in the same direction as the helicopter's nose. Each rocket carries a high explosive warhead with around 2.7 kilograms of explosive materials. The explosion of a single rocket can kill infantry within a radius of several meters of the impact point, and has a high likelihood of disabling or even outright destroying armored vehicles up to and including IFVs. There is some chance to disable or destroy a tank, but it is not high.
FFARs have become the favored weapon for AH-6Ms in ArmA 3, especially due to the reduced effectiveness of the Minigun (see above) in this version of the game. Though ammunition is limited, each pair of rockets fired can have a devastating effect on its target, meaning that only a few rockets are fired in each attack run to achieve a similar effect to thousands of Minigun rounds.
DAGR
The DAGR (Direct Attack Guided Rocket) is an anti-tank guided rocket based on the Hellfire missile system, but adapted for use on small aircraft like the AH-6. DAGRs are laser-guided, flying towards a designated impact point that can be adjusted after launch. They can be fired from a great distance away, and are practically guaranteed to destroy any vehicle they hit, up to and including tanks.
Operating the DAGR requires the AH-6 to have a co-pilot/gunner. The gunner uses the helicopter's nose-mounted camera to spot the target, and will fire the missile at their own discretion. The helicopter should be stabilized by the pilot before firing, since the gunner must keep the camera trained on the target while the missile is in flight. The gunner may adjust the missile's path by pointing the camera at a different location, and can thus track a moving target, or even switch to another target, if the situation requires it.
The number of DAGRs that an AH-6 can carry is very limited. In the few instances where this weapon system appears, the AH-6 usually carries no more than 8 missiles. Thus, each missile must be fired only when a successful hit is deemed likely. DAGRs are typically fired from a great distance away.
Role
The AH-6 is an attack helicopter that specializes in close air support. It hangs around above friendly forces, reacting to any significant target it spots, or any target called out by the ground units. If the AH-6 pilot determines that a target should be attacked from the air, or if asked to attack a target, the AH-6 swoops down and uses its weapons to destroy it.
If the sky is mostly clear of anti-aircraft fire, the AH-6 can venture ahead of friendly forces to perform Interdiction. It will usually scout back and forth over roads, looking for various "soft" targets it can defeat, especially trucks, armored cars and APCs. The AH-6 will rarely interdict enemy infantry unless they are bunched up in a large group, as its weapons are not very efficient against lone infantry or small, spread-out groups.
AH-6s may also be sent to inspect an objective for enemy activity. They will approach the area cautiously using their nose-mounted camera (if available) to scan it from a distance, and report the findings to the ground forces. In some cases, the AH-6 may be instructed to engage particularly dangerous targets found at the location, but only rarely will it engage enemy infantry defending a position.
AH-6 pilots mostly avoid flying over any enemy heavy automatic weapon - such as HMGs or autocannons - as these can shoot the helicopter down very easily. If the weapon is causing problems to air operations, the AH-6 may risk an engagement to quickly destroy it; but this is always risky to the small, unarmored helicopter.
Organization
AH-6s usually operate on their own. They quickly dart about, looking for targets and attacking them, rarely having the need nor the time to fly in formations.
An AH-6 will almost always receive the callsign "Reaper" or "Bandit" (shortened to "Rpr" / "Bdt" on the map). This callsign is typically assigned to close air support aircraft.
If there are two or more AH-6s in the same mission, the callsign "Reaper" or "Bandit" will be followed by a number (e.g. "Reaper One", "Reaper Two", etc.). For the most part, the number makes no functional difference, as the AH-6s are likely to operate independently from one another, patrolling different areas of the battlefield and defending friendly forces from multiple sides. However if they ever need to fly in formation (such as to attack a target in tandem), Reaper One will usually take the lead.
Despite this independent behavior, communications must be maintained with the ground forces at all times. This is normally done on Air Net through the Forward Air Controller, who coordinates between the helicopter and Command. The FAC has some authority over the helicopter, instructing it which targets to attack and when to RTB for rearm. Nevertheless, the pilot of the AH-6 maintains a lot of leeway, and can override commands from the ground if necessary.