An armoured personnel carrier (APC) is a type of armoured fighting vehicle (AFV) designed to transport infantry to the battlefield. APCs are colloquially referred to as 'battle taxis' or 'battle buses', among other things. Armoured personnel carriers are distinguished from infantry fighting vehicles by the weaponry they carry.
The Treaty on Conventional Armed Forces in Europe defines them as "an armoured combat vehicle which is designed and equipped to transport a combat infantry squad and which, as a rule, is armed with an integral or organic weapon of less than 20 millimetres calibre." By convention, they are not intended to take part in direct-fire battle, but are armed for self-defence and armoured to provide protection from shrapnel and small arms fire.
Examples include the American M113, the French VAB, the Dutch-German GTK Boxer and the Soviet BTR.
The genesis of the armoured personnel carrier was on the Western Front of World War I. In the later stage of the war, Allied tanks could break through enemy lines, but the infantry following — who were needed to consolidate the gains — still faced small arms and artillery fire. Without infantry support, the tanks were isolated and more easily destroyed. In response, the British experimented with carrying machine-gun crews in the Mark V* tank, but it was found that the conditions inside the tanks rendered the men unfit for combat. Britain therefore designed the first purpose built armoured troop transport, the Mark IX, but the war ended before it could be put to use.
During World War II, half-tracks like the American M3 and German SdKfz 251 played a role similar to post-war APCs. British Commonwealth forces relied on the full-tracked Universal Carrier. Over the course of the war, APCs evolved from simple armoured cars with transport capacity, to purpose built vehicles. Obsolete armoured vehicles were also repurposed as APCs, such as the various "Kangaroos" converted from M7 Priest self-propelled guns and from Churchill, M3 Stuart and Ram tanks.
During the Cold War, more specialized APCs were developed. The United States introduced a series of them, including successors to the wartime Landing Vehicle Tracked; but the most prolific was the M113 armored personnel carrier, of which 80,000 were produced. Western nations have since retired most M113s, replacing them with newer APCs, many of these wheeled. The Soviet Union produced the BTR-40, BTR-152, BTR-60, BTR-70, BTR-80 in large numbers. The BTR-60 and BTR-80 remain in production. Czechoslovakia and Poland together developed the universal amphibious OT-64 SKOT. A cold war example of a "Kangaroo" is the heavily armoured Israeli Achzarit, converted from captured T-55s tanks.
Weight can vary from 6 to 40 tons or more, but 9 to 20 tons is typical. Most have a capacity of between 8 and 12 dismountable troops, although some can carry more than 20. In addition, it has a crew of at least one driver, many with a gunner and/or commander as well.
An APC is either wheeled or tracked, or occasionally a combination of the two, as in a half-track. Both systems have advantages and limitations.
Tracked vehicles have more traction off-road and more maneuverability, including a minute turn radius. Due to the limited service life of their treads, plus the wear they cause on roads, tracked vehicles are typically transported over long distances by rail, flatbed trucks or purpose built transporters.
Wheeled APCs are faster on road, can cross long distances, and are less expensive to develop, produce, and maintain. However, wheeled vehicles have higher ground pressure than tracked vehicles with a comparable weight, due to tracks having more surface area in contact with the ground. The higher ground pressure increases the likelihood of becoming immobilized by soft terrains such as mud, snow or sand.
Many APCs are amphibious. Their tracks can propel the APC in the water. Wheeled APCs will include propellers or water jets. Preparation for amphibious operations usually comprises checking the integrity of the hull and folding down a trim vane in front. Water traverse speed varies greatly between vehicles. The maximum swim speed of the M113 is 3.8 mph (6.1 km/h), whereas the LAV-25 and AAVP-7 about double that at 6.5 and 8.2 mph (10.5 and 13.2 km/h), respectively.
APCs must provide a minimum amount of protection against small arms fire to be considered as such, though some provide as much protection as a main battle tank, as is the case of the IDF Namer, which is based on a Merkava tank. Armour is usually composed of steel or aluminium. Some APCs also come with NBC protection, which is intended to provide protection from weapons of mass destruction.
Generally APCs will be lighter and less armoured than tanks or IFVs, often being open topped and featuring doors and windows, as seen in the French VAB.
An APC carries a primary weapon no larger than a 20 mm autocannon, before falling into the "infantry fighting vehicle" sub-classification, and will most likely be outfitted with one or more machine guns ranging from 5.56 mm to 7.62 mm. The primary weapon is usually on the top of the vehicle, mounted with either a simple pintle mount, in a small turret, or a remote weapon system.
Pintle-mounted weapons are now rare, due to the lack of crew protection. In World War II, the German Sd.Kfz. 251 half-track was equipped with at least one MG42 or MG34, which could only be aimed in a small arc from whichever end of the vehicle the weapon was mounted and offered minimal protection to the gunner. Turrets provides a traverse of 360 degrees and operator protection. Most APC turrets include a coaxial machine gun (MG) alongside the primary weapon. A recent advent, remote weapon systems (RWS) are used in lieu of pintle mounts and provide the same level of operator protection as a turret, with the added benefit of increased visibility without increasing the overall profile of the vehicle. However, unlike in a turret, the weapon cannot be reloaded from inside the vehicle.
A common primary gun on an APC is a 50 calibre M2 Browning machine gun, or the equivalent 14.5mm KPV heavy machine gun. The Stryker carries an M2 on a CROWS RWS. 7.62 mm machine guns are commonly used as coaxial or secondary weapons. Several Eastern personnel carriers have forward-facing machine guns, or firing ports in the crew compartment. The AAVP7 mounts an M2 50 calibre as a coaxial machine gun, beside a Mark 19 automatic grenade launcher. Occasionally APCs will be equipped with anti-tank missiles.
APCs may be used as armoured ambulances, to conduct evacuations of wounded personnel. These vehicles are equipped with stretchers and medical supplies.
According to article 19 of the Geneva Conventions, "mobile medical units of the Medical Service may in no circumstances be attacked, but at all times be respected and protected by the Parties to the conflict". Although article 22 allows them to carry defensive weaponry, they are typically unarmed. Under Article 39, the emblem of the medical service "shall be displayed ... on all equipment employed in the Medical Service." As such, armoured ambulances will be marked with ICRC recognized symbols.
The infantry fighting vehicle (IFV) is a derivative of the APC. Various classes of infantry fighting vehicles may be deployed alongside tanks and APCs, in armoured and mechanized forces. The fundamental difference between an APC and IFV, is the role they are designed to serve. The CFE treaty stipulates an infantry fighting vehicle is an APC with a cannon in excess of 20 mm, and with this additional firepower the vehicle is more involved in combat, providing fire support to dismounted infantry.
Not all infantry fighting vehicles are equivalent. The primary mechanized infantry vehicle of the Canadian Armed Forces, the lightly armoured LAV-III, is classified as an IFV because it is equipped with a M242 Bushmaster autocannon. The US Army's heavily armoured M2 Bradley carries the same autocannon, plus anti-tank missiles and advanced optics, to serve in armoured divisions alongside M1 Abrams main battle tanks.
Infantry mobility vehicle (IMV) is a new name for the old concept of an armoured car, with an emphasis on mine resistance. They've been primarily used to protect passengers in unconventional theatres of war.
The South African Casspir was first built in the late 1970s. In the 21st century, they gained favour in the post-Soviet geopolitical climate. Identical to earlier Humvees in design and function, the uparmoured M1114 is a clear example of this. The addition of armour grants protection to passengers. M1114s have been largely replaced by purpose built MRAP vehicles.
IMVs generally feature a v-shaped underbelly designed to deflect mine blasts outwards, with additional crew protection features such as four-point seat belts, and seats suspended from the roof or sides of the vehicle. Many feature a remote weapon system. Usually 4x4, these IMVs are distinct from both 8-, 6-, and 4-wheeled APCs (such as the VAB), being closer in appearance to civilian armoured money transporters.