Narrative:

While taxiing to runway 6L accidentally turned onto wrong taxiway and crossed inactive runway 33R. Holding on ramp at ag, there was a great deal of radio chatter on ground frequency. We called several times without an answer. Finally told to taxi to runway 6L on taxiway B hold short of taxiway right. Several more xmissions by ground to other aircraft with corrections and amendments. Ground then told us that air carrier Y would give way and to hold short of taxiway T. There was an air carrier Z, B747, and an air carrier west, DC9, taxiing ahead of us that both turned onto taxiway right and crossed runway 33R. We mistakenly fell in behind them and crossed runway 33R as well. There were no calls from ground control. We called ground when we reached taxiway east and asked for clarification. At that time ground said we had made a wrong turn and cleared us to runway 6L. When switched to tower he said he wanted to pass on that we had turned onto a wrong taxiway and crossed runway 33R without permission. We apologized and admitted we were confused by the repeated changes to taxi clearance. First officer was writing down taxi instructions as best he could with the heavy radio chatter and multiple changes by ground.

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Original NASA ASRS Text

Title: CL65 CREW DID NOT FOLLOW TAXI INSTRUCTIONS AND HAD A RWY INCURSION AT CYYZ.

Narrative: WHILE TAXIING TO RWY 6L ACCIDENTALLY TURNED ONTO WRONG TXWY AND CROSSED INACTIVE RWY 33R. HOLDING ON RAMP AT AG, THERE WAS A GREAT DEAL OF RADIO CHATTER ON GND FREQ. WE CALLED SEVERAL TIMES WITHOUT AN ANSWER. FINALLY TOLD TO TAXI TO RWY 6L ON TXWY B HOLD SHORT OF TXWY R. SEVERAL MORE XMISSIONS BY GND TO OTHER ACFT WITH CORRECTIONS AND AMENDMENTS. GND THEN TOLD US THAT ACR Y WOULD GIVE WAY AND TO HOLD SHORT OF TXWY T. THERE WAS AN ACR Z, B747, AND AN ACR W, DC9, TAXIING AHEAD OF US THAT BOTH TURNED ONTO TXWY R AND CROSSED RWY 33R. WE MISTAKENLY FELL IN BEHIND THEM AND CROSSED RWY 33R AS WELL. THERE WERE NO CALLS FROM GND CTL. WE CALLED GND WHEN WE REACHED TXWY E AND ASKED FOR CLARIFICATION. AT THAT TIME GND SAID WE HAD MADE A WRONG TURN AND CLRED US TO RWY 6L. WHEN SWITCHED TO TWR HE SAID HE WANTED TO PASS ON THAT WE HAD TURNED ONTO A WRONG TXWY AND CROSSED RWY 33R WITHOUT PERMISSION. WE APOLOGIZED AND ADMITTED WE WERE CONFUSED BY THE REPEATED CHANGES TO TAXI CLRNC. FO WAS WRITING DOWN TAXI INSTRUCTIONS AS BEST HE COULD WITH THE HVY RADIO CHATTER AND MULTIPLE CHANGES BY GND.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.