What must you do before connecting the aircraft to the tractor?

Before connecting the aircraft to the tractor, it is essential to unlock the tail wheel. This action is crucial because the tail wheel must be freed to allow for proper maneuvering of the aircraft during towing operations. If the tail wheel remains locked, it can hinder the aircraft's movement and potentially lead to damage during the towing process.

Unlocking the tail wheel ensures that it can pivot and roll freely, aligning with the intended path of the tractor and preventing any unnecessary stress on the aircraft's structure. Proper tail wheel management is a critical step in ensuring safety and efficiency while handling aircraft on the ground.