A combat engineer (also called pioneer or sapper) is a type of soldier who performs military engineering tasks in support of land forces combat operations. Combat engineers perform a variety of military engineering, tunnel and mine warfare tasks as well as construction and demolition duties in and out of combat zones.
Combat engineers facilitate the mobility of friendly forces while impeding that of the enemy. They also work to assure the survivability of friendly forces, building fighting positions, fortifications, and roads. They conduct demolitions missions and clear minefields manually or through use of specialized vehicles. Common combat engineer missions include construction and breaching of trenches, tank traps and other obstacles and fortifications; obstacle emplacement and bunker construction; route clearance and reconnaissance; bridge and road construction or destruction; emplacement and clearance of land mines; and combined arms breaching. Typically, combat engineers are also trained in infantry tactics and, when required, serve as provisional infantry.
Combat engineers play a key role in all armed forces of the world. They are invariably found closely integrated into the force structure of divisions, combat brigades, and smaller fighting units. In many countries, combat engineers are members of a broader military engineering corps or branch. Other nations have distinct combat engineering corps or branches; they are separate from other types of military engineers. The Danish military engineers' corps, for example, is almost entirely organized into one regiment of combat engineers, simply named Ingeniørregimentet ("The Engineering Regiment"). During the War in Afghanistan and the 2003–2011 Iraq War, the U.S. Army tasked its combat engineers with route clearance missions designed to counter rising threats of IEDs. To increase the effectiveness of these units, EOD and mechanic teams were typically embedded with the combat engineer platoon. Due to rising IED threats, the U.S. Army sends some combat engineers to complete Explosive Ordnance Clearance Agent training.
A general combat engineer is often called a pioneer or sapper, terms derived respectively from the French and British armies. In some armies, pioneer and sapper indicate specific military ranks and levels of combat engineers, who work under fire in all seasons and may be allocated to different corps, as they were in the former Soviet Army, or they may be organized in the same corps. Geomatics (surveying and cartography) is another area of military engineering but is often performed by the combat engineers of some nations and in other cases is a separate responsibility, as was formerly the case in the Australian Army. While the officers of a combat engineer unit may be professionally certified civil or mechanical engineers, the non-commissioned members are generally not.
Combat engineers are force multipliers and enhance the survival of other troops through the use and practice of camouflage, reconnaissance, communications and other services. These include the construction of roads, bridges, field fortifications, obstacles and the construction and running of water points. In these roles, combat engineers use a wide variety of hand and power tools. They are also responsible for construction rigging, the use of explosives, and the carrying out of demolitions, obstacle clearance, and obstacle construction, assault of fortifications, use of assault boats in water obstacle crossings, helipad construction, general construction, route reconnaissance and road reconnaissance, and erecting communication installations. Combat engineers build and run water distribution points, carrying out water filtration, and NBC decontamination when necessary, and storage prior to distribution.
All these role activities and technologies are divided into several areas of combat engineering:
Improving the ability of one's own force to move around the battlefield. Combat engineers typically support this role through reduction of enemy obstacles which include point and row minefields, anti-tank ditches, wire obstacles, concrete, and metal anti-vehicle barriers, and Improvised Explosive Devices (IED) and wall and door breaching in urban terrain. Mechanized combat engineer units also have armored vehicles capable of laying short bridges for limited gap-crossing.
Building obstacles to prevent the enemy from moving around the battlefield. Destroying bridges, blocking roads, creating airstrips, digging trenches, etc. Can also include planting land mines and anti-handling devices when authorized and directed to do so.
Building structures which enable one's own soldiers to survive on the battlefield. Examples include trenches, bunkers, shelters, and armored vehicle fighting positions.
Defensive fortifications are designed to prevent intrusion into the inner works by infantry. For minor defensive locations, these may only consist of simple walls and ditches. The design principle is to slow down the advance of attackers to where they can be destroyed by defenders from sheltered positions. Most large fortifications are not a single structure but rather a concentric series of fortifications of increasing strength.
Combat engineers employ a wide range of transportation vehicles and equipment and use weapons unique to the engineers, including those used in land mine warfare.
Basic combat engineering tools include safe use of:
For obstacle breaching, including minefields, the combat engineers use a variety of vehicles, explosive devices, and plastic explosives including:
The Basic Field Manual, Engineer Soldier's Handbook, 2 June 1943 (FM 21-105) was written to provide guidance to a new combat engineer in the United States.