The present disclosure describes an apparatus and a method for inspecting the degradation of a gas nozzle. The nozzle is of the type that can produce a whistle when a gas is blown through the nozzle. The method comprises the steps of detecting an acoustic signal emitted by the nozzle when the gas is blown through the nozzle, the gas having a pressure selected to produce an acoustic resonance at a certain frequency; generating an electrical signal responsive to the detected acoustic signal; band pass filtering the electrical signal at the frequency; and detecting the amplitude of the electrical signal at the frequency. The method also comprises the steps of comparing the amplitude of the electrical signal with a reference amplitude corresponding to a reference nozzle; and displaying a signal indicative of the degradation of the nozzle according to the signal resulting from the comparing step.