Narrative:

Vancouver (yvr) departure handed ADI off to sea center after clearing ADI to maintain 13,000'. Both pilots heard the new frequency as 125.9. This was read back to departure. Departure then said 'good day'. Sea center contacted on 125.9. First officer checked in at 13,000. We received a call of 'roger di, break', then onto another aircraft. Controller continued talking to several other aircraft. Pilots noticed call back had been 'di' not 'ADI' but due to frequency congestion, no call was made to verify that the controller had the correct flight number. Call for di to descend to 12,000' for traffic was received. First officer responded to the call with a readback of the instruction and called out of 13,000 for 12,000. We descended to 12,000' MSL as instructed. The controller then made a call for di to turn to a specific heading. The heading made no sense given our direction of flight. Captain immediately made a call to find out if there was another flight on the frequency with the same or similar call sign. No response was received after several attempts to contact center. Center made several more calls to di. Contact was reestablished with vancouver departure and we were informed that the frequency should have been 125.1. Sea center was immediately contacted on 125.1 and a descent clearance to 7000' was issued. No apparent problems occurred, however, ADI flew for approximately 10 min at the wrong altitude. All could have been avoided if: 1) vancouver departure had caught the wrong frequency on readback. 2) crew had cleared up discrepancy on the call from center (re: di roger). Coincidences: 1) company flight di on frequency. 2) reply at just the right time on check-in. 3) altitude instructions that would be expected on that phase of the arrival.

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Original NASA ASRS Text

Title: ACR MDT CLRNC RESPONSE TO WRONG CALL SIGN ALT DEVIATION EXCURSION FROM CLRNC ALT FREQ CHANGE WRONG.

Narrative: VANCOUVER (YVR) DEP HANDED ADI OFF TO SEA CENTER AFTER CLEARING ADI TO MAINTAIN 13,000'. BOTH PLTS HEARD THE NEW FREQ AS 125.9. THIS WAS READ BACK TO DEP. DEP THEN SAID 'GOOD DAY'. SEA CENTER CONTACTED ON 125.9. F/O CHECKED IN AT 13,000. WE RECEIVED A CALL OF 'ROGER DI, BREAK', THEN ONTO ANOTHER ACFT. CTLR CONTINUED TALKING TO SEVERAL OTHER ACFT. PLTS NOTICED CALL BACK HAD BEEN 'DI' NOT 'ADI' BUT DUE TO FREQ CONGESTION, NO CALL WAS MADE TO VERIFY THAT THE CTLR HAD THE CORRECT FLT NUMBER. CALL FOR DI TO DSND TO 12,000' FOR TFC WAS RECEIVED. F/O RESPONDED TO THE CALL WITH A READBACK OF THE INSTRUCTION AND CALLED OUT OF 13,000 FOR 12,000. WE DESCENDED TO 12,000' MSL AS INSTRUCTED. THE CTLR THEN MADE A CALL FOR DI TO TURN TO A SPECIFIC HDG. THE HDG MADE NO SENSE GIVEN OUR DIRECTION OF FLT. CAPT IMMEDIATELY MADE A CALL TO FIND OUT IF THERE WAS ANOTHER FLT ON THE FREQ WITH THE SAME OR SIMILAR CALL SIGN. NO RESPONSE WAS RECEIVED AFTER SEVERAL ATTEMPTS TO CONTACT CENTER. CENTER MADE SEVERAL MORE CALLS TO DI. CONTACT WAS REESTABLISHED WITH VANCOUVER DEP AND WE WERE INFORMED THAT THE FREQ SHOULD HAVE BEEN 125.1. SEA CENTER WAS IMMEDIATELY CONTACTED ON 125.1 AND A DSCNT CLRNC TO 7000' WAS ISSUED. NO APPARENT PROBLEMS OCCURRED, HOWEVER, ADI FLEW FOR APPROX 10 MIN AT THE WRONG ALT. ALL COULD HAVE BEEN AVOIDED IF: 1) VANCOUVER DEP HAD CAUGHT THE WRONG FREQ ON READBACK. 2) CREW HAD CLRED UP DISCREPANCY ON THE CALL FROM CENTER (RE: DI ROGER). COINCIDENCES: 1) COMPANY FLT DI ON FREQ. 2) REPLY AT JUST THE RIGHT TIME ON CHECK-IN. 3) ALT INSTRUCTIONS THAT WOULD BE EXPECTED ON THAT PHASE OF THE ARR.

Data retrieved from NASA's ASRS site as of August 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.