Chapter Select: "Birds of Prey".
You will be flying an attack helicopter for most of the mission. You will notice many fuel tanks. These are mainly situated on top of buildings and on the sides of some of the roads. Basically anything you shoot that explodes (except the AA guns) is a fuel container. You may get this naturally while playing the mission, but if you want to be safe then fly over the whole map and just shoot any fuel container you see. The trophy will unlock after destroying the 80th one.