This mission is given to you by Martin Madrazo (shown as "Mm" on your map) and can be started by either Michael or Trevor. Martin wants you to kill his cousin, who happens to have some incriminating evidence against him. You'll begin as Michael, so get in a vehicle and head to the observatory.
Once there, get in the marked van like normal, and you'll be manning a pretty powerful gun. Follow the instructions and when you see it, shoot the red squares to hit the engine of the plane. It will take three hits to finally get the plane tumbling towards the ground, which will make you switch to Trevor, who's riding a Sanchez.
You must now tail the plane using Trevor, which will take a bit. There will be a couple of jumps you need to make, or you'll be set back, although you can easily tell where the plane is heading by the black smoke. Since you're on a Sanchez, you want to avoid hitting anything, since you're more than likely going to fall off the bike.
When the plane finally hits the ground, kill Javier and then Trevor will automatically grab the files. The game will now switch to Michael, who needs to get away from the area and then destroy the van. Once you do that, get another vehicle and head back to Martin's place, but you get a call from Trevor, saying to meet him at the cement works. The mission will end after the cutscene.
|Both Michael and Trevor will be unavailable for a short while, meaning you will only be able to play as Franklin.|