A computerized workstation, a set of ultrasonic transducers, and a pool containing a fuel or other fluid storage device are used for leak detection. If the capacity is poor quality or damaged, the air that forms air bubbles in the water will penetrate in the device. The trajectory of the ultrasonic waves emitted by the sensors is suppressed by air bubbles, which makes it possible to pinpoint the defective location. The implemented solution is used in the production of fuel tanks for Volkswagen, BMW and other cars.