Battlefield 3

Play Conquest on any End Game map. Now, your first objective will be to capture the flag with the gunship symbol next to it (usually C) or make sure that your team has it. When you have that flag, you will have to wait for the C-130 gunship to spawn (or respawn) and then you will have the ability to choose "Dropship IFV", which will then drop you from the ship while inside the IFV. Now, when you land, you'll need to get at least 1 kill using the IFV. It is recommended that you aim for enemies that are on foot. Watch out for enemy tanks, helicopters, mines and rockets as the IFV is not very strong.

Once you get a kill an enemy, the achievement will unlock.

You cannot earn this achievement in CTF and must play Conquest on one of the new maps instead.

Much like the gunship in Armored Kill, the C-130 (IFV Tank) will only become available to the team that has captured the base marked with the air vehicle. So that will be your top priority at first. Once your team has control of the base die immediately. If your desperate, remember there is the option to suicide. Provided you were fast enough and no one else already got it, you should now see the option to select “IFV Paradrop”.

This will spawn you in a tank as it parachutes down to earth. It has light armor so you will want to avoid heavy tanks and focus on enemy infantry. It shouldn't be too hard to get a kill if you're careful. I recommend defending the base you needed to capture to get the vehicle spawn. It will be pretty active with enemies also trying to get the achievement.

Thanks to both Sean Reinhardl and R0Y4LEwitCHEESE for confiming you do not need to be the one who drops the C-130. If you're able to find an abandoned one or the secondary gunner seat is open you can still earn the achievement.