Narrative:

Yyz tower cleared us to cross runway 24R taxi to runway 24L and hold at the first hold short line. I understood this to mean the first line that was painted to hold short of runway 24L. After crossing runway 24R we were taxiing across the east runway 24R hold line when the tower ordered us to stop. He had intended that we hold short of the line that would usually apply to wbound aircraft approaching runway 24R. We had crossed this line by half an aircraft length. Other aircraft behind us were also confused by this clearance and requested clarification after hearing our confusion.

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Original NASA ASRS Text

Title: A B737 FLT CREW RECEIVES CONFUSING INSTRUCTIONS AND CROSSES HOLD LINE THAT TWR INTENDED THEM TO HOLD SHORT OF.

Narrative: YYZ TWR CLRED US TO CROSS RWY 24R TAXI TO RWY 24L AND HOLD AT THE FIRST HOLD SHORT LINE. I UNDERSTOOD THIS TO MEAN THE FIRST LINE THAT WAS PAINTED TO HOLD SHORT OF RWY 24L. AFTER XING RWY 24R WE WERE TAXIING ACROSS THE E RWY 24R HOLD LINE WHEN THE TWR ORDERED US TO STOP. HE HAD INTENDED THAT WE HOLD SHORT OF THE LINE THAT WOULD USUALLY APPLY TO WBOUND ACFT APCHING RWY 24R. WE HAD CROSSED THIS LINE BY HALF AN ACFT LENGTH. OTHER ACFT BEHIND US WERE ALSO CONFUSED BY THIS CLRNC AND REQUESTED CLARIFICATION AFTER HEARING OUR CONFUSION.

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.