The Crash

Head to the Fort of Henderson and kill all the undead around the helicopter crash. Grab the secret file inside the chopper then check the blood marks near the stairs. Enter the cellars downstairs afterward.

Once inside, turn to the left to find the Striker Shotgun Mod.

Go downstairs and check the gate. Return back up and enter the other door. Clear the enemies inside and follow the straightforward path until you reach the the staircase.

Once you found the staircase, go down and you'll immediately find the Razor Mod. Find your way to the highlighted area and breach the door. You'll find the wounded pilot inside. Talk to him to update your quest.

Remove the bar from the gate and go upstairs. Exit through the door afterward. Climb the ladder to reach the locked portion of the fort. Enter the tower and pick up the Pride Rifle Mod on the crate across the workbench. Continue upstairs to find Frank Serpo. Talk to him to complete the quest.