A B737 flight crew and cyyz tower have a difference of opinion about what the taxi clearance was.

Attributes
ACN	578914
Time
Date	200304
Day	Mon
Local Time Of Day	1801 To 2400
Place
Locale Reference	airport : cyyz.airport
State Reference	ON
Altitude	agl single value : 0
Environment
Light	Night
Aircraft 1
Operator	common carrier : air carrier
Make Model Name	B737-300
Operating Under FAR Part	Part 121
Flight Phase	ground : taxi
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp
Experience	flight time last 90 days : 60 flight time total : 12000 flight time type : 2000
ASRS Report	578914
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Events
Anomaly	incursion : taxiway non adherence : clearance other anomaly other
Independent Detector	other controllera
Resolutory Action	controller : issued new clearance
Consequence	faa : reviewed incident with flight crew
Supplementary
Problem Areas	ATC Human Performance Flight Crew Human Performance
Primary Problem	ATC Human Performance

Narrative:

We contacted ground control after clearing a landing on runway 5. We heard our instructions to be 'cross runway 15L, hold short taxiway T.' the first officer read back 'cross 15L, hold short taxiway T.' after crossing runway 15L, we turned right on taxiway B proceeding toward taxiway T to hold short. The ground controller informed us as we began our taxi on taxiway B that our clearance had been to taxi on runway 15L. I responded that we understood and read back our clearance to be cross the runway. His response was 'no.' he then added that he would clear the equipment out of our way and to continue taxiing on taxiway B to hold short of taxiway T. This was somewhat confusing to us as we were the only aircraft in sight anywhere on the field and the only equipment was approximately 1/2 mi away snowplowing an interior ramp. We continued taxi without further confusion to the gate. I am not really sure in the future what can be done to improve or eliminate this type of confusion. Had any of the relevant txwys been notamed closed, had there been any other aircraft in sight, had there been any other equipment in sight, then we certainly would have questioned our clearance. At no time was there loss of separation or taxi conflict with ground equipment. There was, however, definite communication error between us and the ground controller.

Original NASA ASRS Text

Title: A B737 FLT CREW AND CYYZ TWR HAVE A DIFFERENCE OF OPINION ABOUT WHAT THE TAXI CLRNC WAS.

Narrative: WE CONTACTED GND CTL AFTER CLRING A LNDG ON RWY 5. WE HEARD OUR INSTRUCTIONS TO BE 'CROSS RWY 15L, HOLD SHORT TXWY T.' THE FO READ BACK 'CROSS 15L, HOLD SHORT TXWY T.' AFTER XING RWY 15L, WE TURNED R ON TXWY B PROCEEDING TOWARD TXWY T TO HOLD SHORT. THE GND CTLR INFORMED US AS WE BEGAN OUR TAXI ON TXWY B THAT OUR CLRNC HAD BEEN TO TAXI ON RWY 15L. I RESPONDED THAT WE UNDERSTOOD AND READ BACK OUR CLRNC TO BE CROSS THE RWY. HIS RESPONSE WAS 'NO.' HE THEN ADDED THAT HE WOULD CLR THE EQUIP OUT OF OUR WAY AND TO CONTINUE TAXIING ON TXWY B TO HOLD SHORT OF TXWY T. THIS WAS SOMEWHAT CONFUSING TO US AS WE WERE THE ONLY ACFT IN SIGHT ANYWHERE ON THE FIELD AND THE ONLY EQUIP WAS APPROX 1/2 MI AWAY SNOWPLOWING AN INTERIOR RAMP. WE CONTINUED TAXI WITHOUT FURTHER CONFUSION TO THE GATE. I AM NOT REALLY SURE IN THE FUTURE WHAT CAN BE DONE TO IMPROVE OR ELIMINATE THIS TYPE OF CONFUSION. HAD ANY OF THE RELEVANT TXWYS BEEN NOTAMED CLOSED, HAD THERE BEEN ANY OTHER ACFT IN SIGHT, HAD THERE BEEN ANY OTHER EQUIP IN SIGHT, THEN WE CERTAINLY WOULD HAVE QUESTIONED OUR CLRNC. AT NO TIME WAS THERE LOSS OF SEPARATION OR TAXI CONFLICT WITH GND EQUIP. THERE WAS, HOWEVER, DEFINITE COM ERROR BTWN US AND THE GND CTLR.

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.