Narrative:

As part of an instrument proficiency check, we were executing the VOR-a approach into north central state airport (sfz), ri (a non-twred airport). This was the last of 3 requested practice approachs for our flight, but the first into sfz (others had been into ewb and pvd). We were operating VFR with an assigned transponder code from pvd approach, initially being vectored within the pvd class C airspace. As we intercepted the approach course, we were 'cleared for the approach,' told to 'remain VFR,' that 'radar service is terminated,' and to 'switch to advisory frequency' by the approach controller (quotation marks show ATC xmissions). We were given no specific missed approach instructions and expected none as this was to be the last practice approach and VMC prevailed. We were also not specifically instructed to 'squawk VFR,' as we were descending from the FAF and outside the class C area, we discussed whether the instructions allowed us to set the transponder to 1200 so that we could simply proceed back to our original departure airport. Since we had informed approach this was our last practice approach and had been told that radar service was terminated, we decided that it was permissible and set the transponder. Our discussion had taken a few moments and by the time I raised the instrument hood we were closer to the airport than I had intended to get, within the active traffic pattern area. This posed a potentially dangerous situation as some traffic was active at the time. I had expected my cfii/safety pilot to help me determine when to break off the approach as I was 'under the hood' but we were both apparently distraction by the transponder code discussion. I immediately exited the pattern and airport area and we returned to our original departure airport flying visually. After the flight terminated, I reviewed the pilot/controller glossary regarding 'radar service terminated' and found no mention of it specifically allowing a transponder code change. By simply flying out of the area, we may have incorrectly changed our transponder code without coordination with and permission from ATC and possibly compounded the situation by not flying the published missed approach procedure. The confusion over the transponder code clearly resulted from a lack of knowledge of the exact meaning of the ATC instructions and can be remedied in the future with further study or perhaps clarification in the aim. The situation at the airport was the result of distrs in the cockpit over the ATC instructions, allowing us to get too close. This would have been dealt with by agreeing before hand just how close we were willing to get to the part before breaking off the approach.

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Original NASA ASRS Text

Title: A PA28-140 PVT PLT QUESTIONS HIS TECHNIQUE OF XPONDER OP AND MISSED APCH PROC USAGE DURING A VFR PRACTICE VOR-A APCH TO AND FROM SFZ, RI.

Narrative: AS PART OF AN INST PROFICIENCY CHK, WE WERE EXECUTING THE VOR-A APCH INTO NORTH CENTRAL STATE ARPT (SFZ), RI (A NON-TWRED ARPT). THIS WAS THE LAST OF 3 REQUESTED PRACTICE APCHS FOR OUR FLT, BUT THE FIRST INTO SFZ (OTHERS HAD BEEN INTO EWB AND PVD). WE WERE OPERATING VFR WITH AN ASSIGNED XPONDER CODE FROM PVD APCH, INITIALLY BEING VECTORED WITHIN THE PVD CLASS C AIRSPACE. AS WE INTERCEPTED THE APCH COURSE, WE WERE 'CLRED FOR THE APCH,' TOLD TO 'REMAIN VFR,' THAT 'RADAR SVC IS TERMINATED,' AND TO 'SWITCH TO ADVISORY FREQ' BY THE APCH CTLR (QUOTATION MARKS SHOW ATC XMISSIONS). WE WERE GIVEN NO SPECIFIC MISSED APCH INSTRUCTIONS AND EXPECTED NONE AS THIS WAS TO BE THE LAST PRACTICE APCH AND VMC PREVAILED. WE WERE ALSO NOT SPECIFICALLY INSTRUCTED TO 'SQUAWK VFR,' AS WE WERE DSNDING FROM THE FAF AND OUTSIDE THE CLASS C AREA, WE DISCUSSED WHETHER THE INSTRUCTIONS ALLOWED US TO SET THE XPONDER TO 1200 SO THAT WE COULD SIMPLY PROCEED BACK TO OUR ORIGINAL DEP ARPT. SINCE WE HAD INFORMED APCH THIS WAS OUR LAST PRACTICE APCH AND HAD BEEN TOLD THAT RADAR SVC WAS TERMINATED, WE DECIDED THAT IT WAS PERMISSIBLE AND SET THE XPONDER. OUR DISCUSSION HAD TAKEN A FEW MOMENTS AND BY THE TIME I RAISED THE INST HOOD WE WERE CLOSER TO THE ARPT THAN I HAD INTENDED TO GET, WITHIN THE ACTIVE TFC PATTERN AREA. THIS POSED A POTENTIALLY DANGEROUS SIT AS SOME TFC WAS ACTIVE AT THE TIME. I HAD EXPECTED MY CFII/SAFETY PLT TO HELP ME DETERMINE WHEN TO BREAK OFF THE APCH AS I WAS 'UNDER THE HOOD' BUT WE WERE BOTH APPARENTLY DISTR BY THE XPONDER CODE DISCUSSION. I IMMEDIATELY EXITED THE PATTERN AND ARPT AREA AND WE RETURNED TO OUR ORIGINAL DEP ARPT FLYING VISUALLY. AFTER THE FLT TERMINATED, I REVIEWED THE PLT/CTLR GLOSSARY REGARDING 'RADAR SVC TERMINATED' AND FOUND NO MENTION OF IT SPECIFICALLY ALLOWING A XPONDER CODE CHANGE. BY SIMPLY FLYING OUT OF THE AREA, WE MAY HAVE INCORRECTLY CHANGED OUR XPONDER CODE WITHOUT COORD WITH AND PERMISSION FROM ATC AND POSSIBLY COMPOUNDED THE SIT BY NOT FLYING THE PUBLISHED MISSED APCH PROC. THE CONFUSION OVER THE XPONDER CODE CLRLY RESULTED FROM A LACK OF KNOWLEDGE OF THE EXACT MEANING OF THE ATC INSTRUCTIONS AND CAN BE REMEDIED IN THE FUTURE WITH FURTHER STUDY OR PERHAPS CLARIFICATION IN THE AIM. THE SIT AT THE ARPT WAS THE RESULT OF DISTRS IN THE COCKPIT OVER THE ATC INSTRUCTIONS, ALLOWING US TO GET TOO CLOSE. THIS WOULD HAVE BEEN DEALT WITH BY AGREEING BEFORE HAND JUST HOW CLOSE WE WERE WILLING TO GET TO THE PART BEFORE BREAKING OFF THE APCH.

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.