Narrative:

During departure and climb to cruise altitude, another aircraft Y had responded several times to clrncs to our aircraft air carrier X. We were given present position direct milford (mlf) climb to 310, to which air carrier Y accepted our clearance. We advised slc ARTCC of the confusion and restated our clearance to mlf at 310 to which slc ARTCC concurred. Several mins later, passing approximately FL298 we received the amended altitude of FL290 due to northbound traffic. We also received a TCASII TA of traffic Z at FL310. The climb was stopped and as we started an immediate descent, slc ARTCC gave us a turn of 30 degrees to increase separation. Slc ARTCC stated he had heard an acknowledgement of the FL290 restr earlier, but we had not responded, so someone else must have read back the restricted clearance for our aircraft. Supplemental information from acn 268046: climbing out of slc to las, ATC issued 2 clrncs to X of which I answered, then corrected my mistake with center. X also acknowledged the error and complied with the clrncs. The confusion occurred because our inbound flight to slc was xx and X was departing in front of us. Supplemental information from acn 268048: on climb out from slc the copilot answered a call from center for flight X. I caught his error instantly and he called center back and told them that he had answered for X but we were Y.

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Original NASA ASRS Text

Title: SIMILAR CALL SIGN. ACR X CLB TO OCCUPIED ALT HAD LTSS FROM ACFT Z. SYS ERROR.

Narrative: DURING DEP AND CLB TO CRUISE ALT, ANOTHER ACFT Y HAD RESPONDED SEVERAL TIMES TO CLRNCS TO OUR ACFT ACR X. WE WERE GIVEN PRESENT POS DIRECT MILFORD (MLF) CLB TO 310, TO WHICH ACR Y ACCEPTED OUR CLRNC. WE ADVISED SLC ARTCC OF THE CONFUSION AND RESTATED OUR CLRNC TO MLF AT 310 TO WHICH SLC ARTCC CONCURRED. SEVERAL MINS LATER, PASSING APPROX FL298 WE RECEIVED THE AMENDED ALT OF FL290 DUE TO NBOUND TFC. WE ALSO RECEIVED A TCASII TA OF TFC Z AT FL310. THE CLB WAS STOPPED AND AS WE STARTED AN IMMEDIATE DSCNT, SLC ARTCC GAVE US A TURN OF 30 DEGS TO INCREASE SEPARATION. SLC ARTCC STATED HE HAD HEARD AN ACKNOWLEDGEMENT OF THE FL290 RESTR EARLIER, BUT WE HAD NOT RESPONDED, SO SOMEONE ELSE MUST HAVE READ BACK THE RESTRICTED CLRNC FOR OUR ACFT. SUPPLEMENTAL INFO FROM ACN 268046: CLBING OUT OF SLC TO LAS, ATC ISSUED 2 CLRNCS TO X OF WHICH I ANSWERED, THEN CORRECTED MY MISTAKE WITH CTR. X ALSO ACKNOWLEDGED THE ERROR AND COMPLIED WITH THE CLRNCS. THE CONFUSION OCCURRED BECAUSE OUR INBOUND FLT TO SLC WAS XX AND X WAS DEPARTING IN FRONT OF US. SUPPLEMENTAL INFO FROM ACN 268048: ON CLB OUT FROM SLC THE COPLT ANSWERED A CALL FROM CTR FOR FLT X. I CAUGHT HIS ERROR INSTANTLY AND HE CALLED CTR BACK AND TOLD THEM THAT HE HAD ANSWERED FOR X BUT WE WERE Y.

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.