This is a bronze achievement worth 10 ganerscore

To get this achievement you must shoot down ten enemies in mission thirteen "throttle"
During this mission you will be flying a fighter jet. You have to destroy 10 of the enemy jets with your machine gun. Don't use rockets. Just hold down the machine gun button all the time and fly close to enemies. The machine gun automatically locks on to targets. Vehicles on the ground can be ignored as they don't count towards this trophy / achievement. If you fail you must restart the mission.