Narrative:

Toronto center cleared us for the runway 24 profile descent with an altitude of 13000 ft MSL approximately 60 mi west of ywt. We called out of our cruise altitude to descend to 13000 ft MSL on the profile descent, then we responded to a descent to a different altitude, 21000 ft. Another aircraft questioned our clearance because it was for them. Toronto didn't correct our response until the other aircraft (similar call signs) corrected them. After the confusion was cleared up, toronto descended us to 11000 ft approximately 25 mi west of ywt. I set 11000 ft in the altitude alerter and the captain acknowledged the clearance (altitude). We proceeded to cross ywt at 11000 ft. The captain (PF) then realized we were to cross ywt at 13000 ft then descend to 11000 ft after crossing ywt as per the profile descent. Toronto mentioned nothing about the altitude. Because of the confusion of call signs by center and not correcting the clearance, our attention was diverted to the altitude 21000 ft then 13000 ft, then cleared to 11000 ft. I am not sure in canada, if an amended clearance like 11000 ft overrides the profile descent of 13000 ft clearance. It can be very confusing. Supplemental information from acn 396690: we got confused with an ensuing clearance and crossed the VOR at 11000 ft, rather than intersection guelf at 11000 ft.

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Original NASA ASRS Text

Title: AN ACR DC9 FLC RESPONDED TO ANOTHER'S CLRNC AND WERE CORRECTED, BUT IN THE CONFUSION DSNDED TOO LOW AT A VOR XING ON THE PROFILE DSCNT. APPARENTLY, NO CONFLICT.

Narrative: TORONTO CTR CLRED US FOR THE RWY 24 PROFILE DSCNT WITH AN ALT OF 13000 FT MSL APPROX 60 MI W OF YWT. WE CALLED OUT OF OUR CRUISE ALT TO DSND TO 13000 FT MSL ON THE PROFILE DSCNT, THEN WE RESPONDED TO A DSCNT TO A DIFFERENT ALT, 21000 FT. ANOTHER ACFT QUESTIONED OUR CLRNC BECAUSE IT WAS FOR THEM. TORONTO DIDN'T CORRECT OUR RESPONSE UNTIL THE OTHER ACFT (SIMILAR CALL SIGNS) CORRECTED THEM. AFTER THE CONFUSION WAS CLRED UP, TORONTO DSNDED US TO 11000 FT APPROX 25 MI W OF YWT. I SET 11000 FT IN THE ALT ALERTER AND THE CAPT ACKNOWLEDGED THE CLRNC (ALT). WE PROCEEDED TO CROSS YWT AT 11000 FT. THE CAPT (PF) THEN REALIZED WE WERE TO CROSS YWT AT 13000 FT THEN DSND TO 11000 FT AFTER XING YWT AS PER THE PROFILE DSCNT. TORONTO MENTIONED NOTHING ABOUT THE ALT. BECAUSE OF THE CONFUSION OF CALL SIGNS BY CTR AND NOT CORRECTING THE CLRNC, OUR ATTN WAS DIVERTED TO THE ALT 21000 FT THEN 13000 FT, THEN CLRED TO 11000 FT. I AM NOT SURE IN CANADA, IF AN AMENDED CLRNC LIKE 11000 FT OVERRIDES THE PROFILE DSCNT OF 13000 FT CLRNC. IT CAN BE VERY CONFUSING. SUPPLEMENTAL INFO FROM ACN 396690: WE GOT CONFUSED WITH AN ENSUING CLRNC AND CROSSED THE VOR AT 11000 FT, RATHER THAN INTXN GUELF AT 11000 FT.

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.