I saw this item this morning. Probably some of you know this already as it's been there for awhile. This may not really pertain to us since we don't do PVP. But basically, if an AIM-120 is fired at you, all you have to do is go into a fast roll (possibly while pulling back on the stick slight), and you'll cause a sync / teleport issue that makes it impossible for the AIM-120 to actually hit you. I don't have much experience with AIM-120's as that's not even an option on the N/A Harrier (it is on the II+ Harriers that have radars, but those are not in DCS), but apparently this works 100% of the time. Doesn't happen in single player - only multiplayer. More info here with a video and tacview clips:
Multiplayer game-breaking bug to avoid AIM-120
Moderator: RLG MGMT Team