A system for thermal inspection of a component having at least one cooling hole, the system comprising: a fluid source configured to supply a warm flow and a cool flow, indirectly or directly, to at least one internal passage of the component; an imager configured to capture a time series of images corresponding to a transient thermal response of the component to the warm and cool flows, wherein the thermal response corresponds to a plurality of intensity or temperature values for an external surface of the component; at least one flow meter configured to measure the warm and cool flows supplied to the component; and a processor operably connected to the imager and configured to: determine the transient thermal response of the component around a transition time, wherein the flow supplied to the component switches from the warm flow to the cool flow at the transition time, and compare the transient thermal response around the transition time with one or more baseline values or with an acceptable range of values to determine if the component meets a desired specification; wherein the processor is configured to determine the transient thermal response by interrogating a second derivative of the intensity or temperature values with respect to time around the transition time; and wherein the processor is further configured to determine a minimum for the second derivative and to compare either the magnitude of the minimum or the time at which the minimum occurs with the one or more baseline values or the acceptable range of values to determine if a respective cooling hole is at least partially blocked. a fluid source configured to supply a warm flow and a cool flow, indirectly or directly, to at least one internal passage of the component; an imager configured to capture a time series of images corresponding to a transient thermal response of the component to the warm and cool flows, wherein the thermal response corresponds to a plurality of intensity or temperature values for an external surface of the component; at least one flow meter configured to measure the warm and cool flows supplied to the component; and a processor operably connected to the imager and configured to: determine the transient thermal response of the component around a transition time, wherein the flow supplied to the component switches from the warm flow to the cool flow at the transition time, and compare the transient thermal response around the transition time with one or more baseline values or with an acceptable range of values to determine if the component meets a desired specification; wherein the processor is configured to determine the transient thermal response by interrogating a second derivative of the intensity or temperature values with respect to time around the transition time; and wherein the processor is further configured to determine a minimum for the second derivative and to compare either the magnitude of the minimum or the time at which the minimum occurs with the one or more baseline values or the acceptable range of values to determine if a respective cooling hole is at least partially blocked. determine the transient thermal response of the component around a transition time, wherein the flow supplied to the component switches from the warm flow to the cool flow at the transition time, and compare the transient thermal response around the transition time with one or more baseline values or with an acceptable range of values to determine if the component meets a desired specification; wherein the processor is configured to determine the transient thermal response by interrogating a second derivative of the intensity or temperature values with respect to time around the transition time; and wherein the processor is further configured to determine a minimum for the second derivative and to compare either the magnitude of the minimum or the time at which the minimum occurs with the one or more baseline values or the acceptable range of values to determine if a respective cooling hole is at least partially blocked.