What should be done before disconnecting a tow bar from the aircraft after a towing operation?

Before disconnecting a tow bar from the aircraft after a towing operation, it is essential to ensure that the aircraft's parking brake is fully set and verified to be holding the aircraft securely. This prevents the aircraft from rolling freely once the tow bar is disconnected, which could lead to a ground collision or other accidents. The proper setting of the parking brake should be confirmed visually and, if possible, through communication with the flight crew. Only after the parking brake is confirmed to be effective should the tow bar's locking mechanisms be released and the tow bar carefully disconnected from both the aircraft and the towing vehicle. This sequence of actions minimizes the risk of uncontrolled aircraft movement.