THE INSTITUTE QUEST 08 - Airship Down
Triggered by completing The Institute quest 07 - End of the Line
Note: This level involves massive firefights with Brotherhood of Steel troops. Make sure to bring good armour or power armour to stay alive on higher difficulties. Energy weapons also work well against the power armour wearing Brotherhood forces.
Objective: Speak to Doctor Li
You'll find Doctor Li in Advanced Systems. She'll fill you in on the plan of assault for the Airport and give you the details about using Liberty Prime to destroy the Prydwen. I'm sure we'll be able to waltz in and there will be no resistance at all, right? Li's assistant will also hand over three special grenades that can be used to teleport in synth allies wherever they are thrown. This can come in very useful during this quest, especially during the final confrontation. Don't waste them just anywhere as you won't be getting any more.
Objective: Use the relay to reach the airport
Walk back to the central area of the Institute and take the elevator all the way up to the relay control room. Step into the relay to arrive on the outskirts of Boston Airport.
Objective: Infiltrate the terminal
This objective can be approached in a couple of different ways. Players with high stealth skills can slowly clear the area outside the wall to the airport. Players without stealth should take solid cover behind one of the outer structures and chew through the oncoming Brotherhood forces until they can enter the airport through the hole in the wall, avoiding the frag mines placed around it. Be careful of the foliage and bushes here as they can obscure enemies from sight making them hard to bring down. They can also occasionally flank and ambush you through the branches so be wary. You'll be dealing with around five or more enemies here.
Objective: Destroy Brotherhood generators
After passing through the hole in the wall, there will be more Brotherhood troops inside so. By now they are probably alerted to your presence unless you have maxed out stealth so take the fight to them. By this point in the game you will likely be dealing with Knight captains (possibly some legendaries as well) so you'll want to use powerful weaponry to bring them down. You can retrieve a fusion core from one of the row of devices inside the chain link fence to the left after entering through the hole as well. Head up the stairs to the right to reach the upper area.
Your goal here is to track down three generators (medium sized glowing devices that look like a circle with three legs). Destroying them quickly will allow institute reinforcements to arrive and help you in the fight against the Brotherhood. The first one is located directly opposite you as you reach the top of the stairs. You should be able to take it out with a well placed shot or two from a long range weapon or you can just sprint across the battlefield and blast it on lower difficulties.
The second generator is in a room directly behind you if you are at the top of the stairs facing the first generator's location. You'll need to circle around the small building to find it. The third and final generator is located up an elevator to your right from the top of the stairs. Pass through the open gap in the wall and enter the elevator to reach the control tower. A protectron and sentry turret will be guarding the generator but they shouldn't pose much of a threat if you managed to fight your way up here.
Objective: Reach Liberty Prime
After the final generator is down, return to the second generators location and pass through the now open double doors. You'll pass a few walls of sandbags before you reach Liberty Prime surrounded by scaffolds. You'll need to battle your way up, taking down anything in your way until you reach the upper level near Prime's head.
Objective: Defend the synth hacking liberty prime (0-100%)
(Optional) Objective: Place teleport beacons
The good news is that the synth will constantly respawn if it's killed. The bad news? There is a ridiculous amount of Brotherhood troops on the way to secure Liberty Prime from you. Elder Maxon will also appear late in the fight with a laser gattling gun and a hell of a chip on his shoulder. Your first thought as a result should be finding a good cover position. I'd advise you to use the hallway you arrived from with the sandbag barricades. This gives you great line of sight on the area (including the upper levels of the scaffold to take out enemies attacking the hacking synth) and solid cover from incoming fire.
Note: You can loot Elder Maxon's body for the legendary weapon Final Judgement
Take advantage of the teleport beacons here as the enemy waves become heavier. The synth will hack in intervals of 25% quite quickly when it isn't under fire, so make sure to keep an eye on it and eliminate any enemies that start climbing the scaffolding. Focus on power armour enemies if you can as the incoming synth forces have a hard time taking them down due to their increased resistance (while chewing through the regular enemies). It is possible to kill all the enemy forces before the hacking is complete (if you let the synth die repeatedly), so it's up to you if you want to fight all the enemies or just try and rush the hack to finish the confrontation quickly. Make sure you start looting when the enemies dry up as you will be teleported away shortly after the hack is complete.
Objective: Evacuate the airport
After the hack reaches 100%, you will have about 35-40 seconds before you teleport away from Liberty Prime to a nearby beach. Watch the results of your labour as Liberty Prime attacks the Prydwen and the quest comes to an end. This begins the final quest for the Institute questline: The Institute Quest 09 - Nuclear Family. Nearly there.