The AI behavior seems to be the exact opposite of what it should initially do in a dogfight. Generally, shouldn't the first priority be energy management? That is, try to maintain a height advantage over the enemy? Is there any way to program the AI to first choose "maintain height" and select "dive away" only when it has lost the tactical advantage or has been damaged in some way? I know this is probably much harder to do than it sounds and may be impossible given the limitations of the game engine, but it would seem to be more realistic, IMO.
What about this idea: the AI "knows" when it is about to auger in and thus levels out before it hits the ground. Could you apply this decision tree so that it triggers level flight (while still evading) upon contact with the enemy? Just a thought...