PLT OF A PA32-300 QUESTIONED BY ATC REGARDING GPS EQUIP. GPS WAS ON BOARD; BUT NOT IFR CERTIFIED. IT WAS USED ONLY TO VERIFY VOR INFO.

Narrative

FILED NATCHEZ; RADAR VECTORS GREENVILLE (HEZ-GLH) AT 5000 FT. CLRED DIRECT GREENVILLE. AFTER TKOF; ZHU ASKED WHETHER WE HAD GPS ON BOARD. WE DO; WITH EXTERNAL ANTENNA; BUT NOT IFR CERTIFIED. ZHU WAS TOLD THIS AND THAT WE WERE PROCEEDING OFF HEZ VOR (6 DEG RADIAL) UNTIL RECEIVING GLH; WHICH IS EXACTLY WHAT WE DID; ALTHOUGH USING GPS TO MONITOR. I BELIEVE THIS IS A LEGAL PROC; BUT AM NOT POSITIVE. HENCE; THE FILING OF THIS RPT. THE WHOLE AREA OF USING NON IFR APPROVED GPS TO FACILITATE NAV NEEDS CLARIFICATION. FOR EXAMPLE; RADAR VECTORS DIRECT TO A DEST 600 MI AWAY WITH THE PLT MONITORING GPS AND SUGGESTING VECTOR CHANGES SEEMS TO ME TO BE A VERY GOOD (AND LEGAL) WAY OF ENHANCING NAV AND LESSENING PLT AND CTLR LOAD. AM I WRONG? (NOTE: APPARENTLY HOUSTON RADAR DOES NOT COVER TKOF AT NATCHEZ; ALTHOUGH I WASN'T AWARE OF THIS UNTIL AFTER TKOF. GPS WAS NOT LISTED AS AVAILABLE EQUIP ON MY FLT PLAN.) CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATES THAT HE HAS NO IDEA WHY ATC ASKED ABOUT THE GPS. IT WAS NOT LISTED ON THE FLT PLAN AND HE NEVER MENTIONED IT TO THEM. HE USED THE GPS ONLY TO BACK UP THE VOR INDICATIONS HE WAS RECEIVING; NOT FOR BASIC NAV. HE IS VERY AWARE THAT THE GPS CANNOT BE USED FOR IFR FLT WHEN NOT CERTIFIED AND WAS NOT DOING SO. HE HAD BEEN GIVEN A VOID CLRNC TIME FOR TKOF AND COMPLIED WITH THAT. HE WAS FLYING A PA32-300 CHEROKEE 6.