A coupling device for supporting a first wing section against a second wing section of an aircraft, and configured for passive flight load alleviation includes a housing including a chamber including a first portion and a second portion and filled with a fluid, a piston device movably arranged in the chamber and separating the first portion from the second portion in a fluid tight manner, a first fluid pathway connecting the first portion to the second portion, a first pressure relief valve arranged in the first fluid pathway and blocking the first fluid pathway, if the pressure in the second portion is smaller than a first relief pressure and opening the first fluid pathway, if the pressure in the second portion is greater than the first relief pressure. In addition, the coupling device can be used to actuate the second wing section against the first wing section.