In GTA: San Andreas, small planes can spawn into the world to perform a fly-by near the player. As former Rockstar developer Obbe Vermeij notes, "sometimes they crash" - the result of several coding errors that the dev has outlined in a recent tweet, and another one that one of the game's modders informed them of nearly 20 years after the fact.
Over on Twitter, Vermeij explained how the planes worked. Before spawning, his code would look for potential obstacles along the flight path, scanning ahead in the direction of the plane's travel. To limit resource-use, the scan only ran out from the main body of the plane and the tips of its wings, but that meant that thin objects might not be detected, setting the planes off on "doomed" paths that would eventually bring them crashing to the ground, with potentially disastrous consequences for the player.
