The AT-400 is a large airplane that commonly spawns flying over urban areas around the State, especially airports. If the player tries to shoot the AT-400 down with any weapon, the airplane will explode and plummet to the ground like any other airplane normally would. However, when the AT-400 hits the ground, it will begin to bounce and spiral continuously, as if it is still trying to get back into the air. Then the AT-400 will freeze in mid-air. This bizarre glitch is a proven phenomenon. The glitch occurs because the game is having a conflict between the plane's AI and the game trying to process the fact that the plane has actually been shot down, unlike most planes, the AT-400 does not have proper coding for crashing due to it's immense size.
There are two ways to repeat this glitch. The first and easiest method is to obtain a Hydra and wait for an AT-400 to spawn flying above you. Then the player must immediately get airborne and shoot the AT-400 down with the Hydra's rockets. A more difficult method of exploiting this glitch is to shoot at the AT-400 from the ground with a homing rocket.