Hi D. Just done a small test,took all the AA guns out of an airbase, and replaced them with my 20mm quad, and it shows damage to my aircraft,i flew across the airfield 5 times. and the results were the same, Well when i say i flew across the airfield, thats not strictly true,after five attemps i never managed to fly from end to end,I got blown to bits every time, Fly over half a dozen 20mm quads. And your in deep *hit. The 20mm flak2 round is classed as a shell in the xpd.