Narrative:

I was in the cockpit of #1 air carrier flight on sep/xa/99 acting as a line check pilot for the flight. I was dividing my time and attention between the pilots and the so who was on his second trip. Nearing the changeover from ZKC to ZDV, the crew acknowledged a clearance from ZKC for #1 air carrier, 'descend to FL310.' there was no reason given for the clearance. We were in cruise at FL350, VMC, on our flight plan route and had not requested nor expected a change of altitude. The crew rogered the clearance by the call sign #1 air carrier and began a gentle descent out of FL350. Shortly after beginning the descent, ZKC gave us a frequency change to ZDV. The crew checked in using #1 air carrier and reported descending to FL310. During this time, either from ZKC or ZDV, the controller transmitted to #2 air carrier, 'confirm you are descending to FL310.' I did not hear the reply. Center asked our flight for its altitude and the crew reported an altitude near FL340. We were shortly given a clearance to climb to FL350 which the crew acknowledged and complied with. I had visual contact with another aircraft on the left side of the aircraft and noticed on the captain's TCASII display that the aircraft was approximately 1200 ft below and 3-5 mi to our left moving in roughly the opposite direction to our flight. There was no TA or RA. I do not recall any controller issuing a caution to #1 air carrier of another flight with a similar call sign at any time during this time frame. Nor do I recall hearing a controller warning to another flight about similar call signs on the frequency. There was no perceived danger or immediate action taken or needed by #1 air carrier during this event. The crew was concerned they had taken another flight's clearance but all in the cockpit believe the initial clearance to descend issued by ZKC was for #1 air carrier. It was only when center queried #2 air carrier as to its altitude did our flight become aware of any possible confusion. At no time did either ZKC and ZDV advise aircraft of the other flts with similar call signs.

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Original NASA ASRS Text

Title: AN ACR FLC FLYING AN L1011 NEAR GLD MISTAKENLY ACCEPTS A DSCNT CLRNC MEANT FOR ANOTHER ACFT WITH A SIMILAR CALL SIGN.

Narrative: I WAS IN THE COCKPIT OF #1 ACR FLT ON SEP/XA/99 ACTING AS A LINE CHK PLT FOR THE FLT. I WAS DIVIDING MY TIME AND ATTN BTWN THE PLTS AND THE SO WHO WAS ON HIS SECOND TRIP. NEARING THE CHANGEOVER FROM ZKC TO ZDV, THE CREW ACKNOWLEDGED A CLRNC FROM ZKC FOR #1 ACR, 'DSND TO FL310.' THERE WAS NO REASON GIVEN FOR THE CLRNC. WE WERE IN CRUISE AT FL350, VMC, ON OUR FLT PLAN RTE AND HAD NOT REQUESTED NOR EXPECTED A CHANGE OF ALT. THE CREW ROGERED THE CLRNC BY THE CALL SIGN #1 ACR AND BEGAN A GENTLE DSCNT OUT OF FL350. SHORTLY AFTER BEGINNING THE DSCNT, ZKC GAVE US A FREQ CHANGE TO ZDV. THE CREW CHKED IN USING #1 ACR AND RPTED DSNDING TO FL310. DURING THIS TIME, EITHER FROM ZKC OR ZDV, THE CTLR XMITTED TO #2 ACR, 'CONFIRM YOU ARE DSNDING TO FL310.' I DID NOT HEAR THE REPLY. CTR ASKED OUR FLT FOR ITS ALT AND THE CREW RPTED AN ALT NEAR FL340. WE WERE SHORTLY GIVEN A CLRNC TO CLB TO FL350 WHICH THE CREW ACKNOWLEDGED AND COMPLIED WITH. I HAD VISUAL CONTACT WITH ANOTHER ACFT ON THE L SIDE OF THE ACFT AND NOTICED ON THE CAPT'S TCASII DISPLAY THAT THE ACFT WAS APPROX 1200 FT BELOW AND 3-5 MI TO OUR L MOVING IN ROUGHLY THE OPPOSITE DIRECTION TO OUR FLT. THERE WAS NO TA OR RA. I DO NOT RECALL ANY CTLR ISSUING A CAUTION TO #1 ACR OF ANOTHER FLT WITH A SIMILAR CALL SIGN AT ANY TIME DURING THIS TIME FRAME. NOR DO I RECALL HEARING A CTLR WARNING TO ANOTHER FLT ABOUT SIMILAR CALL SIGNS ON THE FREQ. THERE WAS NO PERCEIVED DANGER OR IMMEDIATE ACTION TAKEN OR NEEDED BY #1 ACR DURING THIS EVENT. THE CREW WAS CONCERNED THEY HAD TAKEN ANOTHER FLT'S CLRNC BUT ALL IN THE COCKPIT BELIEVE THE INITIAL CLRNC TO DSND ISSUED BY ZKC WAS FOR #1 ACR. IT WAS ONLY WHEN CTR QUERIED #2 ACR AS TO ITS ALT DID OUR FLT BECOME AWARE OF ANY POSSIBLE CONFUSION. AT NO TIME DID EITHER ZKC AND ZDV ADVISE ACFT OF THE OTHER FLTS WITH SIMILAR CALL SIGNS.

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.