I don't know about the rest of you, but here's how I did it...
Drop to wavetops (~100ft/34m) and allow the enemy's planes to pass. Pull up into an Immelmann behind them, and flame the SOBs. On my copy, it was at this point that I got the "Mission Completed" message (this may be the bug).
Yes, I know that the mission is to sink the sub, but after pounding that thing for sorte after sorte and getting nowhere, I just said F- it, and took out the planes. Go figure. Although, when you think about it, why are you trying to take out that sub with only sidewinders, amraams, and a nose cannon? A single harm or maverick would be better suited. Oh, well...
And I'm another one who gives kudos to Bob Dinnerman for his work on this thing. It's still one of my favorites to fly, even moreso than Jane's F/A-18 (PC) or Falcon (any). Dynamix's A-10 and EA's Birds of Prey are close seconds, though.
banzai