Narrative:

We were level at FL310 and experiencing some light chop. I was PF and asked center (ZBW) for FL350 (first officer was busy retrieving an item from his flight bag). The controller responded with 'roger, I have your request, I'll get back to you.' both the first officer and I acknowledged her transmission to each other in the cockpit. I don't remember if either one of us responded on the radio but we probably just gave a 'roger.' about 1 or 2 mins later, I heard (what I thought was) our call sign with a clearance to FL350. The first officer looked over and asked if that was indeed for us and I responded in the affirmative. The first officer read back, 'roger, air carrier x-abyy climb to FL350.' it was followed by silence and we initiated a climb to FL350. At about FL335 the controller asked what our altitude was and we told her FL335 or FL337 (somewhere in that range). She then told us that we were only given an 'expect FL350' clearance and gave us a 30 degree turn to the right. She then cleared us to FL350 and shortly thereafter we heard her give air carrier y-zxxy a clearance. Similar call sign, same altitudes, etc. I think, in retrospect, that our readback probably coincided with air carrier y-axxy's and that's why it wasn't corrected by the controller. In the future I'll just tag on the word 'confirm' when in doubt. I get so used to ATC correcting me if I make an incorrect readback that it enabled me to be complacent.

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Original NASA ASRS Text

Title: AN ACR MLG ACCEPTS A CLB CLRNC TO FL350 THAT WAS INTENDED FOR ANOTHER ACR FLT.

Narrative: WE WERE LEVEL AT FL310 AND EXPERIENCING SOME LIGHT CHOP. I WAS PF AND ASKED CTR (ZBW) FOR FL350 (FO WAS BUSY RETRIEVING AN ITEM FROM HIS FLT BAG). THE CTLR RESPONDED WITH 'ROGER, I HAVE YOUR REQUEST, I'LL GET BACK TO YOU.' BOTH THE FO AND I ACKNOWLEDGED HER XMISSION TO EACH OTHER IN THE COCKPIT. I DON'T REMEMBER IF EITHER ONE OF US RESPONDED ON THE RADIO BUT WE PROBABLY JUST GAVE A 'ROGER.' ABOUT 1 OR 2 MINS LATER, I HEARD (WHAT I THOUGHT WAS) OUR CALL SIGN WITH A CLRNC TO FL350. THE FO LOOKED OVER AND ASKED IF THAT WAS INDEED FOR US AND I RESPONDED IN THE AFFIRMATIVE. THE FO READ BACK, 'ROGER, ACR X-ABYY CLB TO FL350.' IT WAS FOLLOWED BY SILENCE AND WE INITIATED A CLB TO FL350. AT ABOUT FL335 THE CTLR ASKED WHAT OUR ALT WAS AND WE TOLD HER FL335 OR FL337 (SOMEWHERE IN THAT RANGE). SHE THEN TOLD US THAT WE WERE ONLY GIVEN AN 'EXPECT FL350' CLRNC AND GAVE US A 30 DEG TURN TO THE R. SHE THEN CLRED US TO FL350 AND SHORTLY THEREAFTER WE HEARD HER GIVE ACR Y-ZXXY A CLRNC. SIMILAR CALL SIGN, SAME ALTS, ETC. I THINK, IN RETROSPECT, THAT OUR READBACK PROBABLY COINCIDED WITH ACR Y-AXXY'S AND THAT'S WHY IT WASN'T CORRECTED BY THE CTLR. IN THE FUTURE I'LL JUST TAG ON THE WORD 'CONFIRM' WHEN IN DOUBT. I GET SO USED TO ATC CORRECTING ME IF I MAKE AN INCORRECT READBACK THAT IT ENABLED ME TO BE COMPLACENT.

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.