From the game Airforce Delta Strike For the Sony Playstation 2.

Normally, you would have to fly into the barrels of the giant cannons in the Navarrone Valley to destroy the targets at the end. However, due to a glitch, you can sometimes lock onto those targets from the outside of the cannon and your shots will go right through. This seems to work best with a plane that has Multilock-on Ground Missles, such as the MX5000. (It's hilarious to see the Python Units' reaction if you take out the first cannon before they can.)

Taken with permission from Flying Omelette.