FLC OF AN MDT OVERSHOT ASSIGNED DEP ALT DURING RADAR VECTORS ON DEP DUE TO TFC WATCH DISTR. ATC INTERVENED ABOUT ALT OVERSHOOT AT THE TIME THE CAPT WAS RETURNING TO ASSIGNED.

Narrative

WE DEPARTED RALEIGH-DURHAM AT XX25 AND WE WERE CLRED TO 7000 FT INITIALLY. CLBING APPROX AT +/-2500 FPM; THE CAPT WAS HAND FLYING THE AIRPLANE; WHEN SHORTLY BEFORE LEVELOFF ATC CALLED FOR TFC AT 1 O'CLOCK POS. WE STARTED LOOKING FOR THE TFC; BOTH LOOKING OUTSIDE; WHEN THE TCASII CALLED FOR 'TFC; TFC.' BY THE TIME WE SAW THE TFC WE REALIZED THAT WE HAD PASSED THE ASSIGNED ALT BY APPROX +/-600 FT. IMMEDIATELY; BUT IN A SMOOTH MANNER; THE CAPT INITIATED A CORRECTIVE MANEUVER (THE FLT ATTENDANT WAS ALREADY PREPARING TO SERVE). AT THAT TIME ATC CALLED ASKING ABOUT OUR ALT AND WE REPLIED THAT WE WERE DSNDING TO 7000 FT. THE TFC DISTR SHOULD NEVER HAVE LED US TO BOTH LOOK OUTSIDE. INSTEAD WE SHOULD DIVIDE THE TASK BTWN US. ANOTHER WAY TO AVOID A SIT LIKE THIS WOULD BE BY USING THE AUTOPLT IN THE ALT CAPTURE MODE WHICH WOULD LEVEL OFF THE AIRPLANE AT THE ASSIGNED ALT; AVOIDING THIS OCCURRENCE. ANOTHER FACTOR TO MENTION PROBABLY WAS THE FACT THAT IT HAD BEEN A NICE VFR DAY AND WAS THE LAST LEG OF THE DAY. WE WERE MORE RELAXED THAN USUAL; AND WERE CAUGHT BY SURPRISE BY THIS EVENT. IT CAUSED A LACK OF COORD.