Helicopter cabin door locking mechanism

The invention provides a cabin door locking mechanism for a helicopter, which comprises an outer handle assembly, an inner handle assembly, a lock box assembly and a lock seat assembly, and is characterized in that the outer handle assembly comprises an outer lock disc, an outer handle, a button, a first swing arm, a first spring shaft with a first spring, a tension spring and a second swing arm; the outer handle automatically rotates outwards by an angle under the transmission effect that the tension spring pulls the first swing arm, an operator can hold the outer handle conveniently, and when the outer handle is held to continue to rotate outwards, the second swing arm can be driven to rotate in a linkage mode to pull the steel wire rope, so that the lock box assembly and the lock seat assembly can be unlocked; the inner handle assembly comprises an inner lock disc, an inner handle and a second spring shaft, and the second spring shaft can drive the second swing arm to rotate under driving of the inner hand