Aiding the Outcasts

Aiding the Outcasts is a quest and achievement/trophy in the Fallout 3 add-on Operation: Anchorage.

The Brotherhood of Steel Outcasts are trying to acquire advanced military tools, and the only way to enter the vault containing these relics is by completing a military virtual reality simulation only the Lone Wanderer can enter. In the simulation, the Lone Wanderer fights in the Battle of Anchorage, tasked with defending Alaska from invading Red Chinese troops.

Detailed walkthrough
After installing the add-on, the player can use their Pip-Boy to tune into an Outcast distress signal, which automatically adds the quest to the Pip-Boy's quest log. From the emergency signal, the Lone Wanderer learns that Defender Morrill is asking anybody capable of receiving the signal for support at Bailey's Crossroads. Bailey's Crossroads can be reached via Bailey's Crossroads Metro just northeast of the Red Racer factory. This is a fairly standard tunnel system occupied by a few feral ghouls.

At Bailey's Crossroads, a battle is taking place between super mutants and Brotherhood Outcasts, who will mistake the Lone Wanderer for a Brotherhood Outcast if they are wearing Outcast power armor, and will be hostile if they are wearing Brotherhood power armor. The battle progresses through a building until the group reaches the Outcast outpost guarded by mark IV turrets. Once there, Defender Morrill, who led the Outcasts to the outpost, asks the Lone Wanderer to enter the outpost using a freight elevator, then speak with Protector McGraw inside.

At the bottom of the elevator is Defender Sibley, who is not too happy to see the Lone Wanderer (except when wearing Outcast power armor or making use of the Black Widow option); he says to keep quiet and follow him. He leads onward to Protector McGraw who explains that there is some high-tech equipment locked away and only the Lone Wanderer, utilizing the Pip-Boy, can complete the VR program and gain access. This VR program is a simulation of the Anchorage Reclamation. The simulation's safety measures, as a must, have been disabled; dying in the simulator means death in the "real" world as well. The protector then says to follow Sibley to Specialist Olin.

Olin can be found in the room with the simulation pod. She hands over a neural interface suit, which according to her is required to be able to participate in the simulation. After putting the suit on, open the simulation pod and activate it. This quest is concluded and the Lone Wanderer will then be inside the simulation at the beginning of The Guns of Anchorage.

Rewards

 * 100 XP

Bugs

 * If you have completed the first part of the mission, and Defender Sibley is leading you to the Outcast commander, leaving will cause a very odd bug. Sibley will follow you, and will occasionally appear in the oddest places. He has been encountered in the Enclave mobile platform (Broken Steel), outside Rivet City, Raven Rock, the Citadel, in the Republic of Dave, Megaton, Tenpenny Tower and even into DLC areas, such as Point Lookout.
 * It is possible that after downloading Operation: Anchorage at the start of the game, the radio transmission will not be received making it impossible to enter Bailey's Metro.
 * Occasionally the radio signal may be received without having the quest added on the Pip-Boy.
 * After completing the questline and opening the armory door, it is possible that the quest "You Gotta Shoot 'Em in the Head" will appear as completed after activating the power armor on display.
 * You may get stuck in the elevator and have to reload an autosave, but do not wait too long or the game will autosave and you will be stuck in the elevator. This bug occurs more often when having Dogmeat as a companion.
 * After you follow Defender Sibley and enter the pod, the screen could freeze either on the loading screen or right when you enter the simulation.