Narrative:

During initial approach; approach control cleared us to 5000 ft. Then on final; we were cleared to 3500 ft. As aircraft was descending below 5000 ft; I realized that the clearance to 3500 ft did not make sense for this approach. I returned aircraft to 5000 ft; intercepted localizer; and shot approach. The first officer and discussed this and we both felt when the 3500 ft clearance was issued that it was a lower vectoring altitude; but not that low (field elevation 3550 ft MSL). At the gate; I phoned approach control and asked for verification of the event. He informed 3500 ft was the RVR reading for runway 16; not an altitude for the approach. He informed me that training was being conducted during the approach and that no deviation was noted or report was to be filed. The first officer and I experienced some phraseology and communication problems while communicating with approach control. The outcome was a safe stabilized approach; however; we should have caught this error immediately because we had briefed the approach and all altitudes.

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Original NASA ASRS Text

Title: MD80 FLT CREW ON INITIAL APCH STARTS DSCNT AFTER RECEIVING WHAT THEY BELIEVED TO BE AN ATC CLRNC TO 3500 FT. REALIZING THAT THE ARPT ELEVATION WAS 3550 FT; THEY RETURNED TO 5000 FT AND DISCOVERED THAT THE 3500 FT REF WAS TO THE RVR.

Narrative: DURING INITIAL APCH; APCH CTL CLRED US TO 5000 FT. THEN ON FINAL; WE WERE CLRED TO 3500 FT. AS ACFT WAS DSNDING BELOW 5000 FT; I REALIZED THAT THE CLRNC TO 3500 FT DID NOT MAKE SENSE FOR THIS APCH. I RETURNED ACFT TO 5000 FT; INTERCEPTED LOC; AND SHOT APCH. THE FO AND DISCUSSED THIS AND WE BOTH FELT WHEN THE 3500 FT CLRNC WAS ISSUED THAT IT WAS A LOWER VECTORING ALT; BUT NOT THAT LOW (FIELD ELEVATION 3550 FT MSL). AT THE GATE; I PHONED APCH CTL AND ASKED FOR VERIFICATION OF THE EVENT. HE INFORMED 3500 FT WAS THE RVR READING FOR RWY 16; NOT AN ALT FOR THE APCH. HE INFORMED ME THAT TRAINING WAS BEING CONDUCTED DURING THE APCH AND THAT NO DEV WAS NOTED OR RPT WAS TO BE FILED. THE FO AND I EXPERIENCED SOME PHRASEOLOGY AND COM PROBS WHILE COMMUNICATING WITH APCH CTL. THE OUTCOME WAS A SAFE STABILIZED APCH; HOWEVER; WE SHOULD HAVE CAUGHT THIS ERROR IMMEDIATELY BECAUSE WE HAD BRIEFED THE APCH AND ALL ALTS.

Data retrieved from NASA's ASRS site as of January 2009 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.