Narrative:

I was on vectors for the RNAV runway 26 approach into N70. I was being vectored for the final approach. The GPS navigator is a KLN94. I was given a heading then cleared for the approach as the CDI came alive. I turned and tracked the CDI indicator. I believed myself to be between azice and zalga intxns so started a descent to 1700 ft. When I looked on the mfd it shows a turn at zalga. The procedure doesn't have a turn at zalga so I didn't appear to be on course I climbed back up to the MSA until zalga then successfully completed the approach. I'm not sure why the navigator showed the course coming centered when I was not really on a published segment of the approach. I haven't flown this aircraft very much and so am not familiar with the particular GPS as I should be. Lesson learned - - be intimately familiar with avionics; especially when operating IMC. The smart thing I did; climb back to a safe altitude if not certain of my position. I will be spending more time with the GPS manual and fly an approach under VMC to become familiar with the operation of the GPS.callback conversation with reporter revealed the following information: the reporter stated that he programmed the GPS incorrectly. This caused the reported problems on approach.

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Original NASA ASRS Text

Title: LACK OF FAMILIARITY WITH ADVANCED NAVIGATION SYSTEM CONTRIBUTES TO C206 PLT EXPERIENCING CONFUSION AND PREMATURE DSCNT ON APCH TO N70.

Narrative: I WAS ON VECTORS FOR THE RNAV RWY 26 APCH INTO N70. I WAS BEING VECTORED FOR THE FINAL APCH. THE GPS NAVIGATOR IS A KLN94. I WAS GIVEN A HDG THEN CLRED FOR THE APCH AS THE CDI CAME ALIVE. I TURNED AND TRACKED THE CDI INDICATOR. I BELIEVED MYSELF TO BE BETWEEN AZICE AND ZALGA INTXNS SO STARTED A DSCNT TO 1700 FT. WHEN I LOOKED ON THE MFD IT SHOWS A TURN AT ZALGA. THE PROC DOESN'T HAVE A TURN AT ZALGA SO I DIDN'T APPEAR TO BE ON COURSE I CLBED BACK UP TO THE MSA UNTIL ZALGA THEN SUCCESSFULLY COMPLETED THE APCH. I'M NOT SURE WHY THE NAVIGATOR SHOWED THE COURSE COMING CENTERED WHEN I WAS NOT REALLY ON A PUBLISHED SEGMENT OF THE APCH. I HAVEN'T FLOWN THIS ACFT VERY MUCH AND SO AM NOT FAMILIAR WITH THE PARTICULAR GPS AS I SHOULD BE. LESSON LEARNED - - BE INTIMATELY FAMILIAR WITH AVIONICS; ESPECIALLY WHEN OPERATING IMC. THE SMART THING I DID; CLB BACK TO A SAFE ALT IF NOT CERTAIN OF MY POSITION. I WILL BE SPENDING MORE TIME WITH THE GPS MANUAL AND FLY AN APCH UNDER VMC TO BECOME FAMILIAR WITH THE OPERATION OF THE GPS.CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE RPTR STATED THAT HE PROGRAMMED THE GPS INCORRECTLY. THIS CAUSED THE REPORTED PROBS ON APCH.

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.