Narrative:

I was flying my cessna from pdx to lgd on IFR flight plan. At approximately 20 mi from lgd NDB, I noted inability to receive lgd NDB suitable for navigation. 2 other aircraft on frequency also noted no lgd signal. I was #1 for lgd NDB-a approach with another aircraft converging behind me who was having initial difficulty receiving lgd. At about 10 mi out, I advised the controller bke would be my alternate if I was unable to receive lgd NDB. At approximately 6 mi from lgd NDB, I was still unable to receive lgd NDB so I asked to be cleared to initial for VOR DME runway 12 bke approach. Controller cleared me direct to bke VOR 325 degree radial, 20 DME fix, for the DME arc to final. I correctly set in 325 degree radial (145 degrees to) but as my needle centered just outside the arc, I mentally transposed having set in the DME arc radial with the inbound course radial (297 degrees, 117 degrees inbound) and mistakenly thought that I was intercepting the inbound course. I asked the controller if I was being vectored to the inbound course directly or the 325 degree 20 arc fix, and she replied the latter. I continued to insist that I was on the inbound course already and would proceed as cleared. She obviously did not know that I had misread my course setting, so she continued to tell me to proceed to the arc fix (325 degrees, 20 arc fix). When I crossed the arc and failed to turn right to follow the arc wbound to the 297 degree radial, but instead began letting down on the 325 degree radial, she again told me to follow the arc. At this point I realized my error having proceeded to the 16.7 DME fix and let down to about 7700 ft MSL. She vectored me 290 degrees to the arc/final approach fix and told me to climb which I did. Upon reaching the arc/final approach fix I completed the approach without further difficulty. Factors affecting the situation: 1) currency. I am 'legally' current in all required flight operations, but my aircraft had just emerged from 2 months of scheduled and unscheduled maintenance. This decreased my usual 2-3 instrument approachs per month. 2) frustration. The la grande (lgd) NDB has a history of full or partial outages, especially during wet (ie, instrument) WX. I actually began receiving the NDB as I was being vectored to the 325 degree radial, 20 arc fix, but the controller had then cleared the traffic behind me for the approach. So, I knew that if I asked to return for the NDB-a approach in la grande I would have a lengthy hold at lgd NDB and still not be assured of getting into la grande. This frustration tended to distract my concentration on the approach plate for my alternate.

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Original NASA ASRS Text

Title: DEV FROM CLRNC RTE. PLT TRACKS INBOUND ON THE WRONG APCH RADIAL AND STARTS HIS DSCNT. THE ALERT CTLR CORRECTS HIM.

Narrative: I WAS FLYING MY CESSNA FROM PDX TO LGD ON IFR FLT PLAN. AT APPROX 20 MI FROM LGD NDB, I NOTED INABILITY TO RECEIVE LGD NDB SUITABLE FOR NAV. 2 OTHER ACFT ON FREQ ALSO NOTED NO LGD SIGNAL. I WAS #1 FOR LGD NDB-A APCH WITH ANOTHER ACFT CONVERGING BEHIND ME WHO WAS HAVING INITIAL DIFFICULTY RECEIVING LGD. AT ABOUT 10 MI OUT, I ADVISED THE CTLR BKE WOULD BE MY ALTERNATE IF I WAS UNABLE TO RECEIVE LGD NDB. AT APPROX 6 MI FROM LGD NDB, I WAS STILL UNABLE TO RECEIVE LGD NDB SO I ASKED TO BE CLRED TO INITIAL FOR VOR DME RWY 12 BKE APCH. CTLR CLRED ME DIRECT TO BKE VOR 325 DEG RADIAL, 20 DME FIX, FOR THE DME ARC TO FINAL. I CORRECTLY SET IN 325 DEG RADIAL (145 DEGS TO) BUT AS MY NEEDLE CTRED JUST OUTSIDE THE ARC, I MENTALLY TRANSPOSED HAVING SET IN THE DME ARC RADIAL WITH THE INBOUND COURSE RADIAL (297 DEGS, 117 DEGS INBOUND) AND MISTAKENLY THOUGHT THAT I WAS INTERCEPTING THE INBOUND COURSE. I ASKED THE CTLR IF I WAS BEING VECTORED TO THE INBOUND COURSE DIRECTLY OR THE 325 DEG 20 ARC FIX, AND SHE REPLIED THE LATTER. I CONTINUED TO INSIST THAT I WAS ON THE INBOUND COURSE ALREADY AND WOULD PROCEED AS CLRED. SHE OBVIOUSLY DID NOT KNOW THAT I HAD MISREAD MY COURSE SETTING, SO SHE CONTINUED TO TELL ME TO PROCEED TO THE ARC FIX (325 DEGS, 20 ARC FIX). WHEN I CROSSED THE ARC AND FAILED TO TURN R TO FOLLOW THE ARC WBOUND TO THE 297 DEG RADIAL, BUT INSTEAD BEGAN LETTING DOWN ON THE 325 DEG RADIAL, SHE AGAIN TOLD ME TO FOLLOW THE ARC. AT THIS POINT I REALIZED MY ERROR HAVING PROCEEDED TO THE 16.7 DME FIX AND LET DOWN TO ABOUT 7700 FT MSL. SHE VECTORED ME 290 DEGS TO THE ARC/FINAL APCH FIX AND TOLD ME TO CLB WHICH I DID. UPON REACHING THE ARC/FINAL APCH FIX I COMPLETED THE APCH WITHOUT FURTHER DIFFICULTY. FACTORS AFFECTING THE SIT: 1) CURRENCY. I AM 'LEGALLY' CURRENT IN ALL REQUIRED FLT OPS, BUT MY ACFT HAD JUST EMERGED FROM 2 MONTHS OF SCHEDULED AND UNSCHEDULED MAINT. THIS DECREASED MY USUAL 2-3 INST APCHS PER MONTH. 2) FRUSTRATION. THE LA GRANDE (LGD) NDB HAS A HISTORY OF FULL OR PARTIAL OUTAGES, ESPECIALLY DURING WET (IE, INST) WX. I ACTUALLY BEGAN RECEIVING THE NDB AS I WAS BEING VECTORED TO THE 325 DEG RADIAL, 20 ARC FIX, BUT THE CTLR HAD THEN CLRED THE TFC BEHIND ME FOR THE APCH. SO, I KNEW THAT IF I ASKED TO RETURN FOR THE NDB-A APCH IN LA GRANDE I WOULD HAVE A LENGTHY HOLD AT LGD NDB AND STILL NOT BE ASSURED OF GETTING INTO LA GRANDE. THIS FRUSTRATION TENDED TO DISTRACT MY CONCENTRATION ON THE APCH PLATE FOR MY ALTERNATE.

Data retrieved from NASA's ASRS site as of July 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.