SF34 FLC TAXI ACROSS JFK RWY 31R ENRTE TO RWY 31L WITHOUT CLRNC.

Narrative

AFTER A QUICK TURN AND ACFT CHANGE AT JFK WHERE THE GND WAS COVERED WITH 1/2 INCH SNOW AND PATCHY ICE UNDERNEATH; ACR X WAS TAXIING CLOCKWISE ON TXWY A TO RWY 31L. SNOW REMOVAL OPS WERE IN PROGRESS. GND CTL DECIDED TO CHANGE ASSIGNED RWY (OPEN) TO RWY 31R WHICH HAD JUST BEEN CLRED OF SNOW. GND INSTRUCTED US TO 'TAXI VIA TXWY E; HOLD SHORT OF TXWY G.' THAT INSTRUCTION WAS ACKNOWLEDGED BY THE CAPT. AFTER CAREFULLY CHKING THAT RWY 31R WAS CLR; ACR X CROSSED RWY 31R AND CONTINUED ON TXWY E. MEANWHILE; THE FO WAS OCCUPIED SENDING AN ELECTRONIC MESSAGE TO DISPATCH REGARDING AN INOP PWR MGMNT SYS (CTOT). GND QUESTIONED LOCATION OF ACR X WHO REPLIED 'ON TXWY E.' FURTHER TAXI INSTRUCTIONS WERE GIVEN TO RWY 31R VIA TXWY E AND TXWY Y FOR NORMAL TKOF. THE CREW PERCEIVED THAT GND CTL WAS TAKING ADVANTAGE OF A NEWLY CLRED RWY TO ALLEVIATE GND CONGESTION ON RWY 31L; AND THAT NON STANDARD ROUTING WAS DUE TO SNOW REMOVAL OPS IN PROGRESS ON E SIDE OF ARPT. THE CREW FAILED TO BACK EACH OTHER UP DUE TO DISTR AND FAILED TO QUESTION VAGUE NONSTANDARD TAXI INSTRUCTIONS (TXWY E DOES NOT INTERSECT TXWY G). THIS MISSION WAS THE LAST OF A 4-DAY SEQUENCE; WAS RUNNING BEHIND SCHEDULE. THEREFORE; CUMULATIVE FATIGUE AND AN EARLY RPT TIME; AS WELL AS WINTER WX; WERE CONTRIBUTING FACTORS.