well if you want a danger wich will not kill you, then just put 2 shilkas on the highest skill level and they will pretty much shoot the crap outta you, but depending on your position and skill youll survive 8/10
it also depends on the vehicle youre using, if its a blackhawk 2 shilkas are perfect for you, if its a littlebird then only one or youre going down.
the big problem with the planes is that you fly too high for them to fire at you, and when you go lower you are still too fast for them...
since we are on the subject, does anybody know a trigger so that the shilka does kill me (in a blackhawk) with only 2-3 hits? (i want to go down!)