The Nimitz-class aircraft carrier USS Abraham Lincoln (CVN 72) conducted a pre-action aim calibration (PAC) fire on close-in weapons system (CIWS) while underway, Oct. 5.

CIWS is a radar-guided, rapid-fire 20-millimeter Gatling gun that provides Navy ships with defense against anti-ship missiles. This is the first time testing was conducted on CIWS since Abraham Lincoln's half-life Refueling and Complex Overhaul maintenance period.

"Exercises like this ensure that we will have effective defensive measures against any threats that could come our way," said Chief Fire Controlman Chris Steenrod.

The exercise consisted of up to three bursts in both a high-rate of fire and low-rate of fire from each gun. The purpose of the PAC fire is to calibrate the point of radar detection to the point from where the rounds are fired.

Each gun mount is equipped with a fire control assembly and a gun subsystem. The fire control assembly is made up of a radar system for surveillance and detection of targets and a radar system for aiming the gun while tracking the target. The subsystem utilizes a Gatling gun that delivers approximately 75 rounds per second.

"The exercise was excellent," said Fire Controlman 3rd Class Robert Bredan, a CIWS operator. "Our weapons are now calibrated, so it was a success."

When conducting a PAC fire, CIWS operators have several steps they must take to ensure the success of the evolution. Before shooting the CIWS, pre-fire maintenance, involving safety checks and verification rounds, must be completed. Afterwards, post-fire maintenance requires taking apart the guns, verifying the wear and tear of the equipment, re-greasing the moving parts and putting everything back together.

The CIWS shoot is an excellent example of Sailors working together as a team to accomplish one important goal.

"Everybody played a little role in this," said Bredan. "Air boss secured parts of the flight deck, security stood watch to make sure no Sailors came past the hearing hazard zones, safety played a role creating a safety plan and ensuring the exercise was low-risk. All in all, the departments involved executed the exercise with great teamwork."

Abraham Lincoln is underway conducting training.

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