FO OF A B757 OVERSHOT INITIAL CLB ALT DUE TO HIGH RATE OF CLB OF A LIGHT FERRY ACFT AND NOT DISCONNECTING THE AUTOTHROTTLES SOON AFTER TKOF TO REDUCE THE PWR SETTING FOR THE CLB.

Narrative

ALT EXCURSION. FERRY FLT DEPARTED AFW ON RWY 16 FOR DFW. CLRED TO 2000 FT HDG 020 DEGS. TKOF WT WAS 156700 LBS. FO WAS FLYING ACFT. AFTER TKOF ATTEMPTED TO CONTACT DEP CTL; BUT WAS UNABLE. WHILE LOOKING ON CHART TO VERIFY FREQ; I HEARD THE ALT WARNING GO OFF AND SAW WE HAD OVERSHOT TO 2500 FT. BY THIS TIME WE WERE IN CONTACT WITH DEP; WHO QUESTIONED OUR ALT. WE RPTED 2500 FT AND RETURNED TO 2000 FT. SIT MAY NOT HAVE OCCURRED IF AFTER GEAR WAS RETRACTED; AUTOTHROTTLES WERE DISENGAGED AND PWR SET FOR A CLB RATE COMMENSURATE WITH THE 2000 FT RESTR. ALSO BE WARY OF LOOKING AWAY FROM FLT INSTS DURING BUSY PERIODS. SUPPLEMENTAL INFO FROM ACN 364691: SINCE IT WAS A FERRY FLT ACFT WAS VERY LIGHT. IT WAS THE FIRST TIME CAPT AND MYSELF HAVE FLOWN OUT OF AFW. ON DEP CAPT BUSY WITH ATC; WHILE I FLEW ACFT. AT 800 FT AGL I DISCONNECTED AUTOTHROTTLES AND PULLED THROTTLES BACK DUE TO LOW LEVELOFF AND RAPID AIRSPD ACCELERATION; BUT I STILL RECEIVED A SLAT OVERSPD WARNING ON ADI. I FOCUSED MY ATTN TO SLOWING ACFT AND LOST AWARENESS TO ALT. I USED MY ALTIMETER STILL SET TO AFL TO LEVELOFF AT 2000 FT. WE WERE ACTUALLY AT 2500 FT MSL; WHEN ATC AND THE CAPT CONFIRMED I LEVELED OFF 500 FT HIGH.