CL604 FLT CREW HAS AN ALTDEV DURING CLB.

Narrative

WE WERE CLBING OUT OF DALLAS; TX; WITH THE AUTOPLT ENGAGED AND CLRED TO 16000 FT WITH THE ALT PRESELECT SET TO 16000 FT. PASSING THROUGH 15500 FT ON THE DEP WE RECEIVED A CLRNC FROM REGIONAL DEP TO CLB TO 17000 FT AND CONTACT ZFW. I STARTED TO SET THE ALT PRESELECT SO THAT THE AUTOPLT WOULD NOT CAPTURE 16000 FT. AT THAT MOMENT THE CAPT SPILLED SOUP IN HIS LAP AND THE COMMOTION IN THE COCKPIT MUST HAVE DISTR ME FROM SETTING THE ALT PRESELECT TO 17000 FT. AS I READ BACK THE CLRNC I MISSED THE NEW FREQ AND HAD TO ASK FOR IT TO BE REPEATED. I RESET THE RADIO AND CHKED IN WITH CTR. AS I CHKED IN I SAW 20200 FT IN THE ALT PRESELECT AND REALIZED I HAD FAILED TO SET THE ASSIGNED ALT. WE WERE NOW CLBING ABOVE 18000 FT AND LEVELED IMMEDIATELY. I WAS SHOCKED WHEN I SAW MY MISTAKE AND COULDN'T EVEN REMEMBER THE ASSIGNED ALT. ZFW CALLED DEP AND CONFIRMED THAT WE HAD MADE THE MISTAKE AND THEN CLRED US TO FL230. WE WERE TOLD TO CONTACT THE SUPVR WHEN WE LANDED. I THINK THAT THE FACT THAT THE SPILL HAPPENED AT JUST THE WRONG TIME AND THAT I TOOK SO LONG TO SET THE RADIO BOTH CONTRIBUTED TO THE DEV. HAD I NOT BEEN DISTR I WOULD HAVE SET THE PRESELECT CORRECTLY JUST AS I ALWAYS DO. IF THE CAPT HAD NOT BEEN DISTR HE MAY HAVE CAUGHT MY ERROR IN TIME TO CORRECT IT. IF I HAD SET THE RADIO ON THE FIRST TRY I MAY HAVE CAUGHT THE ERROR IN TIME TO CORRECT IT. THE COMPANY STANDARD PROCS WORK WELL AND HAVE ALWAYS REQUIRED THE PNF SET THE ALT AND THE PF TO CHK IT. IN THIS INSTANCE WE WERE BOTH DISTR AT THE SAME TIME RESULTING IN THE DEV.