Follow the MZ on the map with either Trevor or Michael to trigger a meeting outside Martin Madrazzo's house, North-East of Los Santos in his estate called "La Fuente Blanca". Martin takes the two men inside and explains that his coustin, Javier, is conspiring to testify against him in court, and so he wants Michael to kill him. Javier will be flying to Liberty City with some sensitive files and it is Michael's job to shoot down the plane so that Trevor can retrieve the files from the wreckage.
After the cut scene has ended, you now control Michael. Get in Michael's car and follow the yellow route to the Galileo Observatory. Trevor drives off in his Canis Bodhi. Upon arrival, follow the blue dot on the map to the van with an anti-aircraft gun in the back. Get into the drivers seat to bring up the interface.
After the plane begins descending, switch to Trevor on the Sanchez. Once the plane has passed over him, start following it. Start down the dirt pass trail directly ahead, running north through Galileo Park. Follow the smoking trail left by the plane and when the path splits, just keep going North cross-country.
Now follow the Ravine downstream at full speed and then go up the ramp directly ahead and jump over the bus on the highway. Continue down the trail and through the tunnel under the Baytree Canyon Road. When you emerge you will see the plane crossing Senora Road below, then banking along Route 68. It will eventually veer northwards again flying low over the Sandy Shore airstrip which sets up Trevor for another stunt jump over a train. Eventually the plan will glide low over Sandy Shores and Grapeseed before crash landing in an open field.
Get in the can and get out of the area of the observatory, then stop and get out. When Michael emerges, he has carrying a Jerry Can with him. Pour it around the van in a circle, step back a distance and shoot the trail to destroy the van. You now need to make your way back to Madrazzo's house.
As you start on your way back, Trevor calls to tell you there has been a change of plans and gives you a new meeting place.
 Conditions for failure
- Floor It: Achieve top speed while on the Sanchez.
- Glued to the Seat: Don't fall off the Sanchez during the chase.
- One Two Three: Shoot down the plane in only three shots.
- Mission Time: Complete mission within 09:45.