The dependence of an airfoil stall behavior upon the acoustic l environment was experimentally investigated at a Reynolds number of 200,000. The Wortmann FX-63-137-ESM airfoil section was used for the model with an aspect ratio of 4. Some acoustic disturbances could alter the transition process in the shear layer of the separation bubble on the upper surface of the airfoil. These disturbances could delay the deep leading edge stall or hasten stall recovery in some cases. A good agreement was found with the Crabtree criterion to predict the leading edge stall. / Master of Science