JUST BFR TKOF FM RWY 22L ON A NGT IFR FLT, THE PLT WAS CLRD TO CLB & MAINT 2000' & TO CONTACT CHICAGO DEP CTL (TRACON). ABOUT 1 MIN LATER, HE CALLED TRACON & RPRTD HE WAS CLBG THRU 900' FOR 2000'. THIS CALL WAS IN A NORMAL TONE OF VOICE & WAS THE LAST TRANSMISSION FM THE ACFT. SHORTLY THEREAFTER, RADIO & RADAR CONTACT WERE LOST. SUBSEQUENTLY, THE ACFT CRASHED IN A STEEP DSCNT APRX 6000' SOUTH OF THE ARPT & 3200' LEFT OF THE EXTDD RWY CTRLN. THE LAST OF 4 RADAR 'HITS' SHOWED THE ACFT HAD CLBD TO 1300' MSL (ABOUT 700' AGL) BFR THE ACDNT. NO PREIMPACT ENG OR FLT CTL PRBLM WAS FND THAT WOULD HAVE RESULTED IN THE ACDNT, BUT THERE WERE 4 OPEN 'WRITE-UPS' DATED 1/27/87 THAT CONCERNED COCKPIT & INSTRUMENT LGTG. THESE INCLUDED: LEFT SIDE (PLT'S) OVERHEAD FLOOD LGT INOP, PANEL FLOOD LGTS INOP, INTERIOR LGTG CTL KNOB CONSTANT-LY FALLING OFF, PANEL POST LGTS EITHER FULL ON OR OFF. FOR CARGO OPNS, THE MAINT SYS ALLOWED DISCREPANCIES TO BE DELAYEDFOR UP TO SVRL DAYS UNTIL THE ACFT WAS RTRND TO THE HOME BASE.