B747-400 CREW WAS REQUIRED TO MAKE A 180 DEG TURN AFTER LNDG ON RWY 17 AT LAW; BECAUSE TXWY A IS NON LOAD BEARING.

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ON APR/SUN/03; FLEW A MISSION FROM ZZZ TO LAW. WE MADE A NORMAL LNDG ON RWY 17; BECAUSE OF A S WIND (180 DEGS/12 KTS). THE NOTAMS MENTIONED THAT; AFTER A S LNDG; A 180 DEG TURN MUST BE MADE AT THE END OF THE RWY; DUE TO THE S HALF OF TXWY A UNUSABLE; DUE TO LOW BEARING CAPACITY. I STARTED INTO THE 180 DEG TURN. HALF WAY AROUND; BECAUSE I HAD THE NOSEWHEEL TURNED SO FAR; I HAD TO ADD PWR TO KEEP THE ACFT FROM SLOWING TO A STOP. THE ACFT STARTED TO MOVE FORWARD TOWARD THE END OF THE RWY; DUE TO THE NOSEWHEEL SKIDDING. WHEN IT LOOKED LIKE WE COULD SLIDE OFF THE END (CONCRETE SURFACE); I IMMEDIATELY STOPPED THE ACFT AND THE TURN. WE REQUESTED A TUG FROM THE TWR; AND WHEN NONE WAS AVAILABLE AT THIS ARPT; WE THEN REQUESTED SOME KIND OF GUIDEMAN ASSISTANCE. THE MECH SUPPORTING MISSION AT ZZZ DROVE DOWN TO THE END OF THE RWY AND ASSESSED HOW MUCH ROOM WE HAD TO COMPLETE THE TURN AND KEEP THE NOSEWHEEL ON THE CONCRETE SURFACE. HE DECIDED IT WAS SAFE TO CONTINUE; AND THEN MARSHALED US INTO A SHALLOWER TURN ONTO THE TXWY. I NOW HAD TO USE TXWY A AS OUR ONLY CHOICE; AND OF COURSE; A FAR SAFER CHOICE THAN TRYING TO CONTINUE THE 180 DEG TURN. IN MY OPINION; WE SHOULD NOT BE TRYING TO MAKE 180 DEG TURNS AT THIS ARPT IN THIS PARTICULAR OP. THE MARGIN OF SAFETY IS VERY SLIM. IT IS DIFFICULT ON THIS ACFT TO ASCERTAIN EXACTLY WHERE YOUR WHEELS ARE IN RELATION TO THE EDGE OF THE CONCRETE SURFACES. PLUS; WE NEVER PRACTICE MAKING THESE TYPES OF TIGHT TOLERANCE TURNS. THIS IS AN INCIDENT WAITING TO HAPPEN. SUPPLEMENTAL INFO FROM ACN 579141: WHEN FIRST CHKING THE ATIS ON APCH INTO ZZZ; THE WINDS WERE FAVORING A LNDG ON RWY 17 AT LAWTON; BUT WERE LESS THAN 10 KTS. THE NOTAMS INDICATED THE NEED FOR A 180 DEG TURN IN THE EVENT OF LNDG TO THE S DUE TO TXWY A -- S AND B BEING OF LOW BEARING CAPACITY. THE CAPT AND I DISCUSSED LNDG WITH A TAILWIND. INITIALLY; THAT WAS OUR PLAN; BUT BY THE TIME WE WERE CLOSER IN; THE WINDS WERE RPTED AT 180 DEGS AT 10 KTS. WE; THEREFORE; CHOSE TO MAKE A VISUAL LNDG TO THE S. THE CAPT WAS FLYING. AFTER LNDG; WE ROLLED TO THE END WHERE PART OF TXWY A TURNOFF WOULD BE NEEDED FOR THE 180 DEG TURN. THE TURN RADIUS FOR A B747 IS 153 FT AND THE RWY IS 150 FT WIDE. OUR APPROX GROSS WT WAS 50300 LBS. UPON ARRIVING; WE DISCUSSED WITH THE FBO OPERATOR THE NOTAMED TXWY A; WHICH HE SAID WAS USED FREQUENTLY FOR GROSS WT C-5'S. HE FELT THAT IT WAS NOT A PROB. THOUGH WE MAY HAVE HAD A NOTAM; THAT IT WAS UNDER CONSTRUCTION; IT WAS NOT ACTUALLY UNDER CONSTRUCTION. (WE DID SEE SOME CEMENT BEING LAID ADJACENT TO THE TXWY FOR A COMPASS ROSE.) THE OUTCOME WAS THAT WE DID NOT CLOSE THE ARPT; WE DID NOT DO ANY APPARENT DAMAGE TO TXWY A; WE HAD A CLRNC TO TAXI ON TXWY A; AND DIDN'T SEEM TO UPSET THE LCL AUTHS. WE DID; HOWEVER; TAXI VIA A NOTAMED CLOSED TXWY. WE HAD BEEN TOLD THAT MOST OF THE OTHER FLTS HAD LANDED N WHERE THEY COULD TURN OFF AT THE END. A SET OF EYES ON THE GND WOULD BE HELPFUL FOR TURN GUIDANCE IF; IN THE FUTURE; A LNDG TO THE S AT ZZZ WITH A B747-400 IS REQUIRED FOR THE 180 DEG TURN; OR A WAIVER IS OBTAINED FOR TAXI ONTO; AND VIA; TXWY A.