FLT CREW EXITS TYS RWY 23R AT TXWY G4; TO LEARN THE RAMP IS CLOSED TO CIVIL ACFT. FLT CREW HAD PLANED RWY 5L AND G7 EXIT UNTIL LATE CHANGE BY APPROACH CONTROL.

Narrative

WE FLEW INTO TYS EARLY THIS MORNING. IT WAS A SHORT FLT AND BOTH THE CAPT AND I WERE TIRED (NATURALLY IN THE MIDDLE OF THE NIGHT). THE CURRENT WX AT TYS WAS VFR WITH CALM WINDS. WE EXPECTED TO LAND RWY 5L FOR NOISE ABATEMENT PURPOSES. THAT WAS THE RWY WE EXPECTED TO LAND ON WITH A L TURNOFF ON TXWY G7; AS THAT WOULD BE OUR MOST EFFICIENT EXIT TO OUR PARKING POS. ON APCH TO LAND; WE WERE GIVEN A LATE HDOF FROM ZTL TO KNOXVILLE APCH CTL. WE WERE THEN ASSIGNED VECTORS FOR A VISUAL APCH TO RWY 23R. THE SUBSEQUENT VISUAL APCH AND LNDG WERE COMPLETELY SAFE AND UNEVENTFUL WITH NO PROBS. AS WE SLOWED ON OUR LNDG ROLLOUT; WE WERE NOT GIVEN ANY RWY EXIT INSTRUCTIONS FROM THE TWR; SO WE BEGAN A R TURN ONTO TXWY G4 WITH THE LOGICAL IDEA/PLAN OF TAXIING BACK N ON TXWY G TO OUR PARKING RAMP. AS WE BEGAN THE R TURN ONTO TXWY G4; WE CONTACTED THE TWR FOR PROGRESSIVE TAXI INSTRUCTIONS. (NOTE: I HAD NEVER BEFORE BEEN TO THE TYS ARPT AND THE CAPT HAD NOT BEEN THERE FOR MANY YRS.) THE TWR CTLR THEN RESPONDED TO OUR REQUEST FOR TAXI INSTRUCTIONS WITH THE NEWS THAT WE SHOULD NOT USE TXWY G4. WE WERE UNABLE TO PERFORM A 180 DEG TURN AT THAT POINT. OUR COMPANY POLICY PROHIBITS BACKING OF THE ACFT ON THE GND WITH THE USE OF REVERSE THRUST. WE STOPPED; CLR OF THE RWY ON TXWY G4 AND AWAITED FURTHER INSTRUCTION FROM THE TWR. THE PROB: THERE IS A MIL UNIT LOCATED HERE AT THE TYS ARPT THAT UTILIZES TXWY G FROM G1 TO G5. AFTER A BRIEF DELAY WITH A MIL VEHICLE IMPEDING OUR PASSAGE; THE TWR CTLR WAS ABLE TO COMMUNICATE WITH THE MIL UNIT AND WE WERE ALLOWED TO CONTINUE ON TXWY G4 AND TXWY G TO OUR RAMP FOR PARKING. IN SUM; THIS ENTIRE EVENT WAS SIMPLY AN INFRACTION OF THE MIL UNIT'S SPACE AND THE GND AT THE TYS ARPT. I BELIEVE THIS ENTIRE EVENT COULD HAVE BEEN AVOIDED IN A COUPLE OF WAYS: 1) HAD WE AS THE FLT CREW HAD MORE TIME TO REVIEW THE ARPT DIAGRAM; WE WOULD HAVE NOTICED THAT PART OF THE ARPT AS MIL SPACE AND WE WOULD HAVE NEVER HAVE INITIATED AN EXIT TURN FROM THE RWY INTO THAT AREA. 2) HAD OUR LNDG RWY NOT BEEN CHANGED AT THE LAST MIN; WE WOULD NOT HAVE HAD ANY REASON TO UTILIZE THE MIL'S PORTION OF TXWY G. 2) HAD THE TYS TWR CTLR ISSUED US TAXI INSTRUCTIONS BEFORE WE BEGAN OUR EXIT FROM THE RWY AND CALLED THE TWR TO ASK FOR THOSE INSTRUCTIONS. WE HAVE COMMUNICATED WITH OUR COMPANY AND WE HOPE THAT THEY WILL UPDATE OUR COMPANY INFO PAGE WITH A NOTE TO THIS REGARD.