Narrative:

While on the 11 mi DME arc to the ILS at crescent city, ca, I received a false reading on the localizer indicating that the aircraft was on the localizer course. The G/south indicator was indicating that the G/south was below me. I turned the aircraft to the inbound heading and started a descent from 2000'. Center called me at 1000' and told me I was still 9 mi south of the station. I was told to climb to 4000' and return to the 11 mi DME arc. I did climb and eventually received the localizer and G/south indications. The landing was uneventful. What I neglected to do was set the obs indicator to the setting on the chart which would indicate the aircraft was in the correct position to intercept the ILS. My DME was working fine, but I didn't know where I was on the approach because I didn't set the outbnd course indicated in the chart.

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Original NASA ASRS Text

Title: WHILE FLYING A DME ARC TRANSITION TO AN ILS APCH THE REPORTER BECAME DISORIENTED AND PREMATURELY DESCENDED FROM THE TRANSITION ALT AND DEPARTED THE DME ARC.

Narrative: WHILE ON THE 11 MI DME ARC TO THE ILS AT CRESCENT CITY, CA, I RECEIVED A FALSE READING ON THE LOC INDICATING THAT THE ACFT WAS ON THE LOC COURSE. THE G/S INDICATOR WAS INDICATING THAT THE G/S WAS BELOW ME. I TURNED THE ACFT TO THE INBND HDG AND STARTED A DSCNT FROM 2000'. CENTER CALLED ME AT 1000' AND TOLD ME I WAS STILL 9 MI S OF THE STATION. I WAS TOLD TO CLB TO 4000' AND RETURN TO THE 11 MI DME ARC. I DID CLB AND EVENTUALLY RECEIVED THE LOC AND G/S INDICATIONS. THE LNDG WAS UNEVENTFUL. WHAT I NEGLECTED TO DO WAS SET THE OBS INDICATOR TO THE SETTING ON THE CHART WHICH WOULD INDICATE THE ACFT WAS IN THE CORRECT POS TO INTERCEPT THE ILS. MY DME WAS WORKING FINE, BUT I DIDN'T KNOW WHERE I WAS ON THE APCH BECAUSE I DIDN'T SET THE OUTBND COURSE INDICATED IN THE CHART.

Data retrieved from NASA's ASRS site as of August 2007 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.