A B733 CREW; TAXIING FOR TKOF AT PHL; MISINTERPRETED THEIR CLRNC; TAXIING ACROSS AN ACTIVE RWY.

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TAXI OUT TO RWY 9L IN PHL. ON TXWY J TURNED L ONTO K5. TURNED R ONTO TXWY K AND TURNED L ONTO K6; HOLD SHORT OF RWY 9L. GND TOLD US TO CROSS RWY 9L AT APCH END. I WAS SURPRISED GND ISSUED US A CLRNC TO CROSS AN ACTIVE RWY. I THOUGHT TWR WOULD ISSUE THE CLRNC. CROSSED RWY 9L ONTO TXWY W WHEN GND SAID WE HAD CROSSED A RWY WITHOUT CLRNC. NO TFC CONFLICT. GND RADAR WOULD HAVE CAUGHT THIS ERROR IF IT WAS IN USE. GND THOUGHT WE WERE ON TXWY Y. THE PHRASE 'CROSS THE APCH END OF RWY 9L' IS MISLEADING. LOOKING BACK AT THIS INCIDENT THE CTLR MEANT TURN L ON K5; R ON TXWY K; HOLD SHORT OF K6. THEN HE MEANT TAXI DOWN TXWY K; TURN L ON TXWY Y; CROSS APCH END OF RWY 9L ON TXWY Y. FACTORS WERE THE INCLEMENT WX; NIGHT AND NOT USING GND RADAR. SUPPLEMENTAL INFO FROM ACN 538202: WE WERE TAXIING TO RWY 9L AT PHL VIA TXWY J TO SPOT X. WE NEEDED TO PERFORM AN ENG RUN-UP TO START OUR #1 ENG. DUE TO CONGESTION AT THE DEP END OF RWY 9L; GND CTL NEEDED US TO RELOCATE TO A DIFFERENT PART OF THE ARPT FOR OUR ENG RUN-UP. WE WERE GIVEN TAXI INSTRUCTIONS TO TAXI VIA L TURN ONTO K5; R TURN ONTO TXWY K; AND A L TURN ONTO K6. WE COMPLIED WITH THE INSTRUCTIONS AND WERE NOW HOLDING SHORT OF RWY 9L AT K6. GND CTL REQUESTED THAT WE CROSS THE APCH END OF RWY 9L; TAXI VIA TXWYS Y AND P AND HOLD SHORT OF TXWY W. WE READ BACK CROSS APCH END OF RWY 9L; TAXI VIA TXWYS Y AND P AND HOLD SHORT OF TXWY W. WE PROCEED TO CROSS RWY 9L AND WERE LATER INFORMED BY GND CTL THAT WE HAD CROSSED RWY 9L WITHOUT CLRNC. THERE WAS NO TFC CONFLICT ON RWY 9L. THE SIT AROSE FROM A COMBINATION OF WX AND COM. THE CTLR THOUGHT WE WERE AT THE END OF K6 JUST PRIOR TO TXWY Y. K6 STARTS AT THE APCH END OF RWY 9L AND ENDS AT TXWY Y. THE PHRASE 'CROSS THE APCH END OF RWY 9L' IS MISLEADING WHEN ON K6 BECAUSE ONE END FACES THE ACTIVE RWY AND THE W END JOINS TXWY Y. WHEN TAXIING ON TXWY Y YOU DO CROSS THE APCH END OF RWY 9L. GND CTL THOUGHT WE WERE ON TXWY Y. GND RADAR MAY HAVE CAUGHT THIS ERROR IF IT WAS IN USE.