DURING A NIGHT OP A B757-300 FLT IS TAXIED OFF THE TXWY INTO THE SAND WHILE ATTEMPTING TO TAXI TO RWY 35 AT VCV.

Narrative

AFTER RECEIVING CLRNC TO TAXI TO RWY 35 WITH NO RTE INSTRUCTION FROM GND CTL; THE FO AND I BOTH LOOKED AT; AND BRIEFED THE RTE TO THE RWY. THE ARPT DIAGRAM SHOWED TXWY C LED DIRECTLY TO THE END OF RWY 35 WITH NOTHING DEPICTED PAST THAT POINT WHERE IT MADE A R TURN ONTO THE RWY AT C1. NO TXWY OR RAMP IS SHOWN PAST C1. WHILE WE WERE COMPLETING THE BEFORE TKOF CHKLIST WE REALIZED WE MUST HAVE PASSED C1 BECAUSE WHAT TAXI LIGHTS WERE VISIBLE; WERE ENDING. SO WE STOPPED AND QUERIED GND CTL ABOUT THE RWY LOCATION AND THEY SAID WE HAD PASSED IT. BELIEVING I HAD ROOM TO DO SO; I EXECUTED A 180 DEG TURN. MORE THAN HALFWAY THROUGH THE TURN; WE REALIZED WE WERE ON OTHER THAN A PAVED SURFACE. AS THE ACFT BEGAN TO SINK INTO THE DIRT; I STOPPED; SHUT IT DOWN; AND CALLED FOR ASSISTANCE. CAUSES: FLAWED ARPT DIAGRAM; INADEQUATE LIGHTING; TXWY TO NOWHERE; RECESSED TXWY LIGHTS AND THE ILLUSION OF A RAMP BY THE LIGHTS FROM A HANGAR AND SOIL COMPOSITION. IN THE DARK AND IN AN UNKNOWN LOCATION; I SHOULD HAVE REQUESTED A 'FOLLOW ME' VEHICLE. SUPPLEMENTAL INFO FROM ACN 634786: THE ACFT BEGAN TO SINK IN THE DIRT; R WING LOW. THE CAPT STOPPED THE ACFT AND SHUTDOWN THE R ENG.