This page is a walkthrough for The Doomsday Heist Preparation Mission, Flight Path. It’ll navigate you through the necessary steps to successfully acquiring the briefcase.
Eliminate an arms dealer to recover information on the Barrage ATV being flown into Los Santos.
Go to San Andreas Avenue / Steal the Briefcase
Once you’ve started up the mission, take any car and follow the waypoint to San Andreas Avenue. Upon arrival, sit back and wait for the target to finish his conversation.
Wait for him to leave the area, then slowly follow him into the nearby alley and punch him to knock him out. Collect the Briefcase from the floor, then return to your Facility. You’ll be sending out a Global Signal to the other players, so as always beware of people potentially trying to kill you.