FLC OF MD80 HAS 1 MAIN TIRE OFF TXWY SURFACE AT ARA.

Narrative

THE CAPT AND I FERRIED OUR MD80 TO NEW IBERIA; LA; (ARA) FOR PAINT; AND ARRIVED AFTER DARK. NEITHER THE CAPT OR I HAD EVER BEEN INTO THIS ARPT; SO WE ASKED FOR PROGRESSIVE TAXI INSTRUCTIONS; NOTING THAT THE TXWY LIGHTS WERE OTS. THE ARPT IS SERVED BY A PRIMARY NS RWY WITH A PARALLEL TXWY; WHICH HAS 2 STUB TXWYS TO THE RAMP. THE GND CTLR INSTRUCTED US TO TURN L AT THE FIRST TXWY; WHICH WE TOOK TO BE THE FIRST TURN AVAILABLE AS INDICATED ON THE COMMERCIAL ARPT DIAGRAM. NOT DEPICTED ON THE ARPT DIAGRAM; AND JUST N OF THE TXWY; WAS A COMPASS ROSE ADJUSTMENT PAD. AS WE TURNED L ONTO THE CTRLINE; IT BECAME APPARENT TO ME THAT THIS WAS NOT A TXWY; AND I SAID 'THIS ISN'T RIGHT; IT'S A COMPASS ROSE.' AS THE CAPT LOOKED AT OUR OPTIONS; HE MANEUVERED THE ACFT TO SEE IF THERE WAS ENOUGH ROOM TO MAKE A 180 DEG TURN. IT DID NOT APPEAR TO BE ENOUGH; SO WE SHUT DOWN AND CALLED FOR TOWING ASSISTANCE. WHILE WAITING FOR THE TUG I LOWERED THE AIRSTAIRS AND WENT OUT FOR A LOOK AND FOUND OUR R MAIN PARTIALLY OFF THE PAVED SURFACE. WE WERE TOWED ONTO THE RAMP AND THE ACFT WAS INSPECTED TO ENSURE THAT NO DAMAGE HAD OCCURRED.