US Field artillery team
The purpose of the advance party security with METT-T and the absence of enemy troops, mines, booby traps, NBC hazards, and so on.
The battery commander can coordinate for additional troops to clear areas of small enemy forces, obstacles, and minefields.
Using a standardized format, the FO sends either an absolute position or a position relative to another point, a brief target description, a recommended munition to use, and any special instructions, such as "danger close" (a warning that friendly troops are close to the target, requiring extra precision from the guns).
In the spring of 1931, the Gunnery Department successfully demonstrated massing battalion fire using this method, which was used extensively by field artillery during World War II.
In a typical heavy division configuration, there exists two FDC elements capable of operating two four gun sections, also known as a split battery.
Elevation (vertical direction) and bearing orders are specified in mils, and any special instructions, such as to wait for the observer's command to fire relayed through the FDC.
The crews load the howitzers and traverse and elevate the tube to the required point, using either hand cranks (usually on towed guns) or hydraulics (on self-propelled models).
Artillery gunners are taught how to use direct fire to engage a target such as mounted or dismounted troops attacking them.
With indirect fire, in normal artillery missions, the crews manning the guns cannot see their target directly, or observers are doing that work for them.
There have been exceptions to this situation, but even when US Marines assaulted Iwo Jima during World War Two, and gunners could see the impact of their rounds on Mount Suribachi, the actual adjustment of their fire was accomplished by forward observers directly supporting and attached to infantry units, because they were in the position not only to see the enemy but to prevent friendly fire incidents and to coordinate shelling the Japanese with their infantry unit's movements.
