It depends on the plane, and where you're sitting in the plane.
In the US, most cesna 182's.....
_Am
FAR 91.307 c
"Unless each occupant of the aircraft is wearing an approved parachute, no pilot of a civil aircraft carrying any person (other than a crewmember) may execute any intentional maneuver that exceeds--
1) A bank of 60 degrees relative to the horizon
2) A nose-up or nose-down attitude of 30 degrees relative to the horizon."
I thought this rule also applied to any aircraft whenever the door is opened in flight, but couldn't find that published anywhere.