An in-flight test article mounted on a Cessna O-2A Skymaster studying the effect of forward- and aft-facing steps on swept-wing boundary-layer transition is described. An accurate instrumentation suite, consisting of a five-hole probe, static pressure ports, and an infrared camera is presented. Pressure coefficient profiles compare favorably with a computational validation. Infrared thermography is used as a global transition detection technique. Step height and transition location based Reynolds numbers are computed and compared with unswept transition studies. Based on the current data, the addition of the crossflow instability is believed to reduce the critical step height Reynolds number for both forward- and aft-facing steps.
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