I have exact the same problem. I came back from my second "Flashback/War" mission and now i have to fly to hayden again. Well i cant even start to fly, because as soon as the loading screen is done and i press start in my briefing screen i see myself sitting in the helicopter, the rotors are flying around and the message "your helicopter is too heavyly damaged" pops up (In german, because i use the german languane).
I really hope there will be help from you guys, cause actually i cant play it anymore and that sucks big time. I really enjoyed it - bought it yesterday and now this. :-( very disapointing.