Narrative:

I was flying from cho to 1a5 at 12000 ft cruise altitude. ZTL (or approach, I'm not certain) had me switch to ashville approach. They descended me to 10000 ft then switched me back to atlanta which then had me descend to 9000 ft. The next instruction was 'PA30, descend and maintain 3000 ft' which I read back thinking we must be in the valley that contained the airport (1a5) with an elevation of 2020 ft. Upon descent, I checked the GPS and it seemed the aircraft was too far away for me to descend that low. There was a mountain in front of me, probably between me and the airport. About the time I decided to call atlanta and question my clearance to 3000 ft (I was at 8300 ft) atlanta called me and asked if I was descending. I answered 'affirmative, descending to 3000 ft.' controller asked 'who told you to descend.' I answered, 'the last controller, I read back the clearance with a questioning tone in my voice.' the controller said 'PA30, do not descend below 7000 ft.' then silence. More than once it seemed they had trouble hearing me and asked me 'how do you read?' I heard them clearly. Soon I was in the valley over 1a5, canceled IFR (I was in clear air) and landed. I did not hear ZTL talking to other aircraft so I don't know what caused this situation, perhaps controller error. If I had answered for another aircraft then the controller would have corrected me. Perhaps there was radio interference and controller did not hear me. Still, he should have called until I answered correctly.

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Original NASA ASRS Text

Title: CFTT INCIDENT WHEN A PA30 CFI STARTS AN UNAUTH DSCNT THAT WOULD HAVE PLACED HIM BELOW ENRTE TERRAIN 30 NM NE OF DEST ARPT OF 1A5, NC.

Narrative: I WAS FLYING FROM CHO TO 1A5 AT 12000 FT CRUISE ALT. ZTL (OR APCH, I'M NOT CERTAIN) HAD ME SWITCH TO ASHVILLE APCH. THEY DSNDED ME TO 10000 FT THEN SWITCHED ME BACK TO ATLANTA WHICH THEN HAD ME DSND TO 9000 FT. THE NEXT INSTRUCTION WAS 'PA30, DSND AND MAINTAIN 3000 FT' WHICH I READ BACK THINKING WE MUST BE IN THE VALLEY THAT CONTAINED THE ARPT (1A5) WITH AN ELEVATION OF 2020 FT. UPON DSCNT, I CHKED THE GPS AND IT SEEMED THE ACFT WAS TOO FAR AWAY FOR ME TO DSND THAT LOW. THERE WAS A MOUNTAIN IN FRONT OF ME, PROBABLY BTWN ME AND THE ARPT. ABOUT THE TIME I DECIDED TO CALL ATLANTA AND QUESTION MY CLRNC TO 3000 FT (I WAS AT 8300 FT) ATLANTA CALLED ME AND ASKED IF I WAS DSNDING. I ANSWERED 'AFFIRMATIVE, DSNDING TO 3000 FT.' CTLR ASKED 'WHO TOLD YOU TO DSND.' I ANSWERED, 'THE LAST CTLR, I READ BACK THE CLRNC WITH A QUESTIONING TONE IN MY VOICE.' THE CTLR SAID 'PA30, DO NOT DSND BELOW 7000 FT.' THEN SILENCE. MORE THAN ONCE IT SEEMED THEY HAD TROUBLE HEARING ME AND ASKED ME 'HOW DO YOU READ?' I HEARD THEM CLRLY. SOON I WAS IN THE VALLEY OVER 1A5, CANCELED IFR (I WAS IN CLR AIR) AND LANDED. I DID NOT HEAR ZTL TALKING TO OTHER ACFT SO I DON'T KNOW WHAT CAUSED THIS SIT, PERHAPS CTLR ERROR. IF I HAD ANSWERED FOR ANOTHER ACFT THEN THE CTLR WOULD HAVE CORRECTED ME. PERHAPS THERE WAS RADIO INTERFERENCE AND CTLR DID NOT HEAR ME. STILL, HE SHOULD HAVE CALLED UNTIL I ANSWERED CORRECTLY.

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.