GA PLT IS CONFUSED BY APCH CTLR'S HOLDING INSTRUCTIONS IN AGS AIRSPACE.

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ON A SHORT FLT FROM CAE TO AIK; APCHED AIK AND WAS ADVISED BY AUGUSTA APCH TO EXPECT TO HOLD AT THE AIK NDB. I SET THE PUBLISHED HOLDING PATTERN UP IN THE GPS AND EFIS; BUT WHEN I RECEIVED HOLDING INSTRUCTIONS I UNDERSTOOD THE CTLR TO SAY 'HOLD ON THE AIKEN 330 DEG RADIAL; MAKE THAT THE 330 DEG BEARING FROM THE AIK NDB; AT 5000 FT EXPECT FURTHER...' I THEN ASKED IF IT WAS POSSIBLE TO HOLD AS PUBLISHED; BUT WAS TOLD THAT THAT PROC WAS IN ANOTHER CTLR'S AIRSPACE. I HASTILY CHANGED THE ADF TO FLY THE HOLDING PATTERN AS INSTRUCTED AND CHANGED THE EFIS AND GPS SYS TO REFLECT THE NEW HOLDING PATTERN AS I INTERPRETED HIS INSTRUCTIONS. THE ENTRY WAS LESS THAN PERFECT; BUT AFTER RETURNING TO THE NDB; THE NEXT TURN WAS FINE. MY CONCERN; HOWEVER; IS THAT I MAY HAVE BEEN ON THE WRONG SIDE OF THE NDB. AFTER LOOKING AT THE PLATES AND THINKING ABOUT THE CTLR SECTORS IT IS POSSIBLE THAT HE WANTED ME ON THE SE SIDE OF THE ARPT; WHICH WOULD HAVE BEEN A 330 DEG BEARING 'TO' THE NDB. WHILE THE CTLR DID NOT SAY ANYTHING TO ME TO INDICATE THAT I WAS WRONG; THIS CONFUSION COULD HAVE BEEN AVOIDED HAD I SIMPLY ASKED FOR CLARIFICATION BY INQUIRING WHETHER HE WANTED ME TO HOLD ON THE NW OR SE SIDE OF THE NDB. MY CONFUSION WAS FURTHERED BY MY INSISTENCE ON REPROGRAMMING THE 'FANCY' GPS/EFIS SYS RATHER THAN JUST USING THE TRIED AND TRUE NDB SYS AND 'FLYING THE AIRPLANE.' ONCE AGAIN; I HAVE REINFORCED IN MY MIND THE IMPORTANCE OF; 'WHEN IN DOUBT; ASK.' CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE PLT STATED THAT HE THOUGHT THAT HE HELD IN ACCORDANCE WITH THE INSTRUCTIONS GIVEN BY THE CTLR; AND THAT NO TELEPHONE CONTACT WAS REQUESTED BY THE CTLR FOLLOWING THE FLT.