Narrative:

Climbing out of atl on departure control frequency, first officer flying, cleared to 14000 ft. Just prior to reaching 14000 ft, departure said 'slow to 250 KTS.' I read back, 'roger, 2-5-0.' I gave radio control to first officer. I turned off frequency to talk with flight attendants about possible electrical problem/emergency. We were experiencing light to moderate chop in and out of clouds at the time. Since I was busy, first officer questioned departure about the 'climb to 2- 5-0' which he thought he heard me read back to departure control 125.0. Departure said 'roger.' note: we were having difficulty communicating due to slight static from being in clouds, and first officer was flying and talking while encountering the very rough air. As we climbed through 15400 ft, departure called and said we had left our altitude and to return immediately. No conflict. He stopped the climb about 16500 ft and started to descend to 14000 ft. Descending through 14800 ft, departure said, 'climb immediately to 16000 ft to avoid traffic at 14000 ft.' (we picked up traffic at 14400 ft on TCASII.) we climbed to 16000 ft. I got back on departure control frequency when first officer signaled that we had climbed through altitude. Contributing factors: 1) attention to electrical problem. 2) flight conditions. 3) only 1 pilot communicating. 4) bad communications turnover on my part prior to getting off departure frequency.

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Original NASA ASRS Text

Title: AN ACR MD88 FLC DEPARTED THEIR ASSIGNED ALT WHEN THE FO INTERPED AN AIRSPD ASSIGNMENT TO BE AN ALT ASSIGNMENT.

Narrative: CLBING OUT OF ATL ON DEP CTL FREQ, FO FLYING, CLRED TO 14000 FT. JUST PRIOR TO REACHING 14000 FT, DEP SAID 'SLOW TO 250 KTS.' I READ BACK, 'ROGER, 2-5-0.' I GAVE RADIO CTL TO FO. I TURNED OFF FREQ TO TALK WITH FLT ATTENDANTS ABOUT POSSIBLE ELECTRICAL PROB/EMER. WE WERE EXPERIENCING LIGHT TO MODERATE CHOP IN AND OUT OF CLOUDS AT THE TIME. SINCE I WAS BUSY, FO QUESTIONED DEP ABOUT THE 'CLB TO 2- 5-0' WHICH HE THOUGHT HE HEARD ME READ BACK TO DEP CTL 125.0. DEP SAID 'ROGER.' NOTE: WE WERE HAVING DIFFICULTY COMMUNICATING DUE TO SLIGHT STATIC FROM BEING IN CLOUDS, AND FO WAS FLYING AND TALKING WHILE ENCOUNTERING THE VERY ROUGH AIR. AS WE CLBED THROUGH 15400 FT, DEP CALLED AND SAID WE HAD LEFT OUR ALT AND TO RETURN IMMEDIATELY. NO CONFLICT. HE STOPPED THE CLB ABOUT 16500 FT AND STARTED TO DSND TO 14000 FT. DSNDING THROUGH 14800 FT, DEP SAID, 'CLB IMMEDIATELY TO 16000 FT TO AVOID TFC AT 14000 FT.' (WE PICKED UP TFC AT 14400 FT ON TCASII.) WE CLBED TO 16000 FT. I GOT BACK ON DEP CTL FREQ WHEN FO SIGNALED THAT WE HAD CLBED THROUGH ALT. CONTRIBUTING FACTORS: 1) ATTN TO ELECTRICAL PROB. 2) FLT CONDITIONS. 3) ONLY 1 PLT COMMUNICATING. 4) BAD COMS TURNOVER ON MY PART PRIOR TO GETTING OFF DEP FREQ.

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.