A WESTWIND II24 FLC GETS CONFUSED DURING A NIGHT TAXI OP AND CROSSES RWY 4L DEP END WHILE TRYING TO ESTABLISH THE LOCATION OF TXWY Z AT EWR; NJ.

Narrative

WE WERE TAXIING N ON TXWY P. TWR TOLD US TO TURN W ON TXWY Z. AS WE TURNED ONTO TXWY Z; THE CAPT FELT THAT THE TXWY WAS INDEED FURTHER N. HE THEN MADE A 180 DEGS AND STARTED E TO GO FURTHER N AGAIN TOWARD WHAT HE THOUGHT WAS TXWY Z. THE TWR QUESTIONED OUR TURN AND HAD US STOP ON A SOUTHERLY HEADING. AT THIS TIME WE WERE N OF TXWY Z AND VERY CLOSE TO THE HOLD SHORT LINE FOR RWY 4L. TWR INSTRUCTED US TO TAXI W ON TXWY Z AND HOLD SHORT OF RWY 4L. BEING CLOSER THAN WE EXPECTED TO RWY 4L WE FOUND OURSELVES 15-30 FT BEYOND THE HOLD SHORT LINE. RATHER THAN MAKE THE SIT ANY WORSE; THE CAPT CONTINUED ACROSS AND WE STOPPED ON THE OTHER SIDE OF RWY 4L; AS THIS WAS THE DEP END OF RWY 4L. FROM THERE; TWR GAVE US OFF TO GND CTL AND WE CONTINUED TO THE FBO. CLRLY THE BIGGEST CONTRIBUTING FACTOR WAS OUR UNFAMILIARITY OF THE ARPT; AS WELL AS OUR REFUSAL TO ASK FOR ASSISTANCE AT A BUSY ARPT. SINCE THIS OCCURRENCE; WE HAVE FLOWN 3 OTHER TIMES. BOTH OF US AGREE TO MERELY SLOW DOWN; OR STOP (IF ABLE) WHEN WE FEEL AS THOUGH SOMETHING IS NOT RIGHT.