Narrative:

On approach to dtw on ILS 3R with wind from the northeast about 20 KTS and in IMC. We were stabilized on approach and in fairly smooth flight conditions. Just inside the final approach fix at around 2;000 ft we got the aural alert that the autopilot disengaged. The first officer who was flying took control of aircraft and saw airspeed dropping significantly and added power and then decided to perform a missed approach go around. As this was happening speed decreased about 15-18 KTS below our vref speed of 142 KTS to around 125 KTS and we received a momentary stick shaker. We completed the missed approach and advised ATC that we were executing a missed due to either wake turbulence (we were told we were 6 miles in trail of a heavy 767) or was it wind shear. Since we had no wind shear alert or warning and no other indication except the disconnection of autopilot and the airspeed reduction we could not tell. After returning for a landing and discussing it with the first officer he said he did notice he did have about 70% N1 while on the approach prior to the incident. I don't know how this could have been prevented. There was no indication of anything wrong until the autopilot aural alert that it disconnected on its own. Due to being above 1;500 ft we had no wind shear warning and the approach until that point was stable and smooth. Don't know if we hit wake turbulence from preceding aircraft or wind shear. Our next approach to same runway was uneventful but was noticeably more turbulent even prior to reaching the final approach fix. I believe we responded quickly and correctly when we assessed the situation.

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Original NASA ASRS Text

Title: A CRJ Captain reported that the First Officer executed an IMC missed approach when the aircraft lost 15-18 KTS on approach. The crew is uncertain if the turbulence was a wake from a preceding B767 or a wind shear.

Narrative: On approach to DTW on ILS 3R with wind from the northeast about 20 KTS and in IMC. We were stabilized on approach and in fairly smooth flight conditions. Just inside the final approach fix at around 2;000 FT we got the aural alert that the autopilot disengaged. The First Officer who was flying took control of aircraft and saw airspeed dropping significantly and added power and then decided to perform a missed approach go around. As this was happening speed decreased about 15-18 KTS below our Vref speed of 142 KTS to around 125 KTS and we received a momentary stick shaker. We completed the missed approach and advised ATC that we were executing a missed due to either wake turbulence (we were told we were 6 miles in trail of a heavy 767) or was it wind shear. Since we had no wind shear alert or warning and no other indication except the disconnection of autopilot and the airspeed reduction we could not tell. After returning for a landing and discussing it with the First Officer he said he did notice he did have about 70% N1 while on the approach prior to the incident. I don't know how this could have been prevented. There was no indication of anything wrong until the autopilot aural alert that it disconnected on its own. Due to being above 1;500 FT we had no wind shear warning and the approach until that point was stable and smooth. Don't know if we hit wake turbulence from preceding aircraft or wind shear. Our next approach to same runway was uneventful but was noticeably more turbulent even prior to reaching the final approach fix. I believe we responded quickly and correctly when we assessed the situation.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.