The opportunity to get this happens at the end of the mission Fracture Jaw, upon reaching Firebase Ripcord.
Start by making sure you take out the vehicles below you as you come around the corner into the open area. Now, the most important part to get this achievement is to get the mortar teams which are located on the ground but do not have any markers on them. You can see the trail of their mortars in the air when they shoot, and your crosshairs will turn red when you are aimed at them.
Do a counter-clockwise rotation around the hilltop scanning the ground for these mortar teams while taking out the main objective vehicles when convenient. Keep trying until you are asked to land. If you are unsuccessful, you will have to retry.