A combat engineer is a military specialist in using the tools and techniques of engineering under combat conditions.
In Ancient times, combat engineers were responsible for siege warfare and building field fortifications, temporary camps and roads. The best engineers of the ancient times were probably the Romans, who constructed hugh siege-machines (catapults, battering rams and siege towers) as well as constructing fortified wooden camps and paved roads for their legions.
In the Middle Ages combat engineers focused mainly on siege warfare. They planned castles and fortresses. When laying a siege, they planned and oversaw the efforts to penetrate through the castle's defences. When the first cannons appeared, combat engineers were responsible for maintaining the cannons while planning counter-artillery fortifications.
In the United States Army, the three tasks of the combat engineer are mobility, countermobility, and survivability.
- Mobility: improving your own force's ability to move around the battlefield and transport supplies. Can include constructing bridges, roads, airfields, seaports and other facilities. See also logistics. May include removing and disarming landmines and booby traps.
- Countermobility: building obstacles to prevent the enemy from moving around the battlefield. Destroying bridges, blocking roads, cratering airstrips, digging trenches, etc. Can also include planting landmines and booby traps although this is controversial under international law.
- Survivability: building structures which enable one's own soldiers to survive on the battlefield. Trenches, bunkers, shelters, fighting positions.
In the Israeli Defence Forces the Combat Engineering Corps have several roles beside those who written above:
- Sapper: trained with all the basic engineering skills and also trained at high infantry level. His main role is to bridge through terrain obstcales (natural and artificial) and enable ground forces to advance in the battle field.
- Heavy Equipement Operator: less combatant but nonetheless important, these soldiers are skilled in the operation of heavy mechanical equipment such as heavy bulldozers, cranes, tractors and mine-breaching devices. The Israeli HEO, TZAMA, are most famous for operating the armoured Caterpillar D9 bulldozer.
- NBC Disposal: they are expert in handling nuclear, biological and chemical threats.
- EOD experts: the Explosive Ordinance Disposal are experts in detonating explosives without damage. Among their equipment you can find the Barret M82A1 and remote-control EOD robots with shotguns and mechanic-arms. The EOD are the military equivelant of the police's bomb squad.
- Demolition experts: they are specially trained in blowing up things in the most accurate and effective way. They blow things starting from cellular phones and doorlocks up to tanks and large buildings. In the IDF, the demolition experts are united in a Sayaret (Israeli name for SF elite unit) and therefore gain high infantry training as well.