Spinning unit of an air jet spinning machine and the operation of such a machine

A method for operating an air jet spinning machine, wherein the air jet spinning machine features at least one spinning unit with a spinning nozzle for producing a yarn, the method comprising:

• during normal operation of the spinning unit, feeding a fiber composite to the spinning nozzle through an inlet and in a predefined transport direction, wherein the fiber composite within a vortex chamber of the spinning nozzle receives a twist with the assistance of a vortex air flow, such that a yarn is formed from the fiber composite, the yarn leaving the spinning nozzle through an outlet;
• spooling the yarn on a sleeve with assistance of a spooling device;
• carrying out a piecing process after an interruption in the yarn production wherein a yarn end from a spool side of the spinning nozzle is moved counter to the transport direction through the spinning nozzle, is overlaid with an end of the fiber composite after passing through the spinning nozzle, the overlaid yarn end and fiber composite end brought through the inlet into the spinning nozzle;
• during the piecing process, applying an additive to the end of the fiber composite;
• and
• after conclusion of the piecing process, resuming production of the yarn in the normal operation.