My personal thought it's that the losses of more Apaches than cobras it's just because the "running fire" tactics of the marines and of course the number of sorties.
Have you seen a cobra doing a high hover attacks?
Have you seen a cobra low and slow flying over n Iraki city?
Surely you have seen an Apache doing those things.
From the images I have seen in TV Cobras were just doing close support (in the best way), coming from the back of the marines , shooting and then breaking hard.
Anyway...
I have found these images that I want to share
http://hal9000.inetstrat.com/crash/ah64.html Looks pretty good crash resistant.
Regards.