What is the maximum wind velocity in which doors can be opened and slides can be deployed safely, without flying away on the A 320 series?
Out of FCOM:
Wind for passenger / cargo door operation :
Maximum wind for passenger door operation : 65 knots
Maximum wind for cargo door operation : 40 knots (or 50 knots, if the aircraft nose is oriented into the wind, or the cargo door is on the leeward side).
The cargo door must be closed, before the wind speed exceeds 65 knots.