Most people don’t have a very good idea how the Army is organized. Given that the Army uses a jargon to designate units, this is pretty understandable. Mostly, the Army is organized under “The Rule of Three to Five”. The concept behind the rule is “span of control”. Typically, a leader can only effectively lead three to five subordinate units. Any more than that and control becomes problematic. It is just too hard to keep track of things. Various units are organized in different ways, but for our example, we’ll use my first unit, a light infantry division in the mid 80′s. The organization has changed since then, but this will give you some idea of how things work.
The smallest element in the infantry is the “fire team”. This consists of a Team Leader, typically a Sergeant (E-5), armed with an M-16, an Automatic Rifleman armed with an M-249 Squad Automatic Weapon (SAW, basically a light machine gun), a Grenadier armed with an M-16 with the M203 40mm grenade launcher attached, and a Rifleman armed with an M-16. Notice that this gives the team a balance of weapons, and with a leader and three subordinates, follows the 3-5 rule.
The next step up is the squad, and it is actually the exception to the rule, in that it has only two subordinate units. Two Fire Teams are paired with a Squad Leader, usually a Staff Sergeant (E-6). The two teams allows the squad leader to use one team as a base of fire, while the other team maneuvers to assault the enemy. Three squads are used to make up a platoon.
Platoons are lead by a Second Lieutenant or a First Lieutenant (O-1 or O-2), with a Sergeant First Class (E-7) as his Platoon Sergeant. In addition to the three rifle squads, there is a weapons squad that belongs to the platoon, which has two medium machine gun teams. This is a pattern we will see repeated where a unit has 3 maneuver elements and a supporting weapons element. The platoon also has a small headquarters element with Radiotelephone Operators for the Platoon Leader and Platoon Sergeant. If other folks like medics or forward observers are loaned to the platoon (we would say “attached”) they would be part of the headquarters.
The next echelon is the Rifle Company. A Rifle Company is Commanded by a Captain (O-3) who is assisted by his First Sergeant (E-8). There are three rifle platoons, a weapons platoon, and a headquarters. The weapons platoon consists of two 60mm mortars, and a section of anti-tank gunners with a medium antitank missile. In my day, this was the M-47 Dragon, but now it is the Javelin, a much, much better weapon. The company headquarters, in addition to the CO and the 1SG, had RTOs for the CO, an armorer to fix the weapons, a supply sergeant, a Nuclear, Biological & Chemical Warfare NCO, and usually some attachments from the higher echelons, such as an artillery forward observer team. Again, we follow the 3-5 rule and have a supporting weapons element. Incidently, much like your own civilian organizations, re-orgs happen all the time. In the two years I was in Hawaii, the antitank section went from belonging to the company, then belonging to the platoons, then back to the company.
The Infantry Battalion is the parent unit for rifle companies, and is pretty much the smallest unit that will operate indepentently. A Light Infantry Battaltio consisted of three rifle companies and a Headquarters & Headquarters Company (HHC). An Infantry Battalion (BN) is commanded by a Lieutenant Colonel (O-5). He has an Executive Officer who is a Major (O-4) and a Command Sergeant Major (E-9).
He also has a staff to assist him with. There are four principal staff officers. S-1 deals with personnel and is typically a Captain. S-2 is the Intelligence Officer and is usually a Captain, but sometimes a senior First Lieutenant. The S-3 is the Operations, Plans & Training Officer and is a Major. The S-4 is the Logistics Officer and is usually a Captain. Each of these staff officers has a section of people working for them, usually a couple of junior officers, some mid-grade NCOs and a few private soldiers.
In addition, the BN CO has some special staff officers such as a chaplain. The HHC was a combination of weapons and support elements. There was an anti tank platoon with TOW missiles mounted on jeeps or Hummers, an 81mm mortar platoon, and a Scout platoon. For support, there was a medical platoon, a Support platoon with 15 or so Hummers for transport, a commo section, and a maintainence section. Most of the support elements worked for the staff officers, so we aren’t really violating the 3-5 rule. Basically, the BN CO had to coordinate and lead the three rifle companies to accomplish his mission. We’ll take a look at higher echelons at some point in the future.