Narrative:

I was PF on this flight from dfw to cll. Departure control stepped us up to 8000 ft rather quickly, where we remained for some time. Later, we were stepped up by ZFW, but I don't remember to what altitude. Climbing through 10000 ft, I informed my first officer that I would be off the frequency in order to give the company required PA regarding the seat belt sign (which I turned off) and the use of portable electronic devices. After returning to the frequency, my first officer informed me of the changes. I don't remember if there were any. The altitude selector indicated 13000 ft and the aircraft climbed on autoplt with 2000 FPM toward that altitude. At about 12500 ft ZFW called us, rather upset, asking about our altitude and giving us the impression that we were not climbing fast enough. On our TCASII we noticed a fast moving target at our 4 O'clock position, approximately 2 NM, indicating 12200 ft, same direction. There was no TA or RA at any time. Moments later my first officer acquired the aircraft visually as it passed us well off to our right. After we were turned over to ZHU (at 13000 ft) we were given a phone number to call ZFW after landing, which I did. I was told that there would be an investigation about a deviation regarding my flight, as we had been cleared to 11000 ft and not 13000 ft. Because I was unaware of any deviation until I talked to center more than an hour later, I do not remember all the details of the flight. However, there was a similar sounding call sign (last 2 digits were the same) on the frequency and ZFW was very busy. Contributing factor was the loss of communications redundancy while I was giving the PA.

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Original NASA ASRS Text

Title: ALTDEV RESULTS IN LTSS.

Narrative: I WAS PF ON THIS FLT FROM DFW TO CLL. DEP CTL STEPPED US UP TO 8000 FT RATHER QUICKLY, WHERE WE REMAINED FOR SOME TIME. LATER, WE WERE STEPPED UP BY ZFW, BUT I DON'T REMEMBER TO WHAT ALT. CLBING THROUGH 10000 FT, I INFORMED MY FO THAT I WOULD BE OFF THE FREQ IN ORDER TO GIVE THE COMPANY REQUIRED PA REGARDING THE SEAT BELT SIGN (WHICH I TURNED OFF) AND THE USE OF PORTABLE ELECTRONIC DEVICES. AFTER RETURNING TO THE FREQ, MY FO INFORMED ME OF THE CHANGES. I DON'T REMEMBER IF THERE WERE ANY. THE ALT SELECTOR INDICATED 13000 FT AND THE ACFT CLBED ON AUTOPLT WITH 2000 FPM TOWARD THAT ALT. AT ABOUT 12500 FT ZFW CALLED US, RATHER UPSET, ASKING ABOUT OUR ALT AND GIVING US THE IMPRESSION THAT WE WERE NOT CLBING FAST ENOUGH. ON OUR TCASII WE NOTICED A FAST MOVING TARGET AT OUR 4 O'CLOCK POS, APPROX 2 NM, INDICATING 12200 FT, SAME DIRECTION. THERE WAS NO TA OR RA AT ANY TIME. MOMENTS LATER MY FO ACQUIRED THE ACFT VISUALLY AS IT PASSED US WELL OFF TO OUR R. AFTER WE WERE TURNED OVER TO ZHU (AT 13000 FT) WE WERE GIVEN A PHONE NUMBER TO CALL ZFW AFTER LNDG, WHICH I DID. I WAS TOLD THAT THERE WOULD BE AN INVESTIGATION ABOUT A DEV REGARDING MY FLT, AS WE HAD BEEN CLRED TO 11000 FT AND NOT 13000 FT. BECAUSE I WAS UNAWARE OF ANY DEV UNTIL I TALKED TO CTR MORE THAN AN HR LATER, I DO NOT REMEMBER ALL THE DETAILS OF THE FLT. HOWEVER, THERE WAS A SIMILAR SOUNDING CALL SIGN (LAST 2 DIGITS WERE THE SAME) ON THE FREQ AND ZFW WAS VERY BUSY. CONTRIBUTING FACTOR WAS THE LOSS OF COMS REDUNDANCY WHILE I WAS GIVING THE PA.

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.