Emergency opening system of an aircraft cabin door

An emergency opening system of an aircraft cabin door mounted in an aircraft fuselage structure comprising

• a stiff hinge arm being at a fuselage flank pivotable supported in said aircraft fuselage structure, said aircraft cabin door being pivotable supported by said hinge arm at a door flank of the hinge arm,
• an actuator, designed to assist the opening of the aircraft cabin door against the force of gravity by means of a gas operated actuating rod, said actuator being mounted with its fix end to said hinge arm and said actuating rod being connected to an actuator joint of a four joint gear,
• a drivable fork lever of said four joint gear linked to said actuator joint, and
• a bell crank of said four joint gear being respectively pivotable mounted to said stiff hinge arm and to said actuator joint, wherein
• the four joint gear is provided with at least one coupling lever and at least one coupling joint, said at least one coupling lever being rotatable joint to said fork lever at said at least one coupling joint and said at least one coupling lever being mounted in at least one hinge of the stiff hinge arm by means of at least one torsion bolt of said four joint gear, said at least one torsion bolt being drivingly connected to said aircraft cabin door for rotation of said aircraft cabin door.