Armored Core Wiki

Icebreaker Defense Mission Icon

Icebreaker Defense is a mission in the third chapter of Armored Core 4.


  • Area: Antarctic Ocean
  • Objective: Protect allied tanker
  • Client: BFF


  • Damage: 12800 AP (14800 AP on hard mode)
  • Ammo Use: N/A
  • Mission Time: 330 seconds


Allied Tanker

The BFF allied tanker being defended.

Let's confirm the mission.

A BFF ice-breaking tanker is being followed by a fleet of unidentified subs. Eliminate the subs and protect that tanker.

According to aerial surveillance, we're dealing with a comparatively large fleet of Omer's Agadir-class combat subs.

Protecting that tanker is your first priority. Sink all of the subs while avoiding their arsenal or large vertical-launch missiles.

Those are your orders.


The player begins the mission on the deck of the ice-breaking tanker, and the objective is to protect the ship from long-range missile attacks from the enemy submarine fleet. Tracking and destroying the submarines may be difficult, as they remain submerged and invisible until they are ready to launch their missiles. They also surface at various locations on the map, potentially bypassing the player and hitting the tanker with their missiles.

The mission only requires that the tanker survives, and the player may choose to remain with the tanker and intercept the submarines' missiles rather than go after the submarines directly. The mission ends once the tanker reaches the edge of the combat area, or once all of the enemy submarines are destroyed.

Hard Mode Differences: A squadron of enemy autogyros will arrive to reinforce the submarine fleet. They are mostly used to distract the player from intercepting the submarines' missiles, although they can cause significant damage to the tanker if not intercepted.




Fiona Jarnefeldt:Enemy submarine fleet has entered the combat area. Take them all out while guarding that ice-breaking tanker.

Fiona Jarnefeldt:(Hard Mode)Enemy reinforcements now approaching combat area. It's an aerial squadron--mostly autogyros. They're packing large slug guns. Take them down before they can get close.

Fiona Jarnefeldt:Undersea activity detected. Enemy reinforcements confirmed--more submarines.

Fiona Jarnefeldt:3 remaining enemy sub signatures.

Fiona Jarnefeldt:2 remaining enemy sub signatures.

Fiona Jarnefeldt:All subs are surfacing! They're preparing a missile fuselage. Guard that tanker.

Fiona Jarnefeldt:1 remaining enemy sub signature.

Fiona Jarnefeldt:Submarine fleet completely destroyed. The mission was a success. Good work. Please head back.