THE PLT WAS ON AN IFR FLT IN IMC & RCVD CLNC TO CLIMB & MAINT FL220. DRG CLIMB, HE INFORMED ARTCC, '. . . WE'RE HAVING A PROBLEM.' WHEN ASKED TO SAY AGAIN, HE BGN THE SAME REPLY, THEN NO FURTHER RDO COM WAS RCVD FM THE ACFT. SUBSEQUENTLY AN INFLT BREAKUP OCCURRED & WRECKAGE WAS SCATTERED OVR A WIDE AREA. THE RGT OUTBOARD WING PANEL, HRZNTL STABILIZER, ELEVATORS, RGT AILERON & PARTS OF THE RUDDER WERE FND AT A DSTC FM THE MAIN WRECKAGE. THESE DISPLAYED EVIDENCE OF OVERSTRESS FAILURE. NO PREEXISTING CRACKS OR FATIGUE WAS FND. RADAR & WX DATA SHOWED DEV FM NORMAL FLT BGN AT OR NR MDT CONVECTIVE WX ECHO (VIP 2) AS THE ACFT WAS CLIMBING THRU 17,300' IN FRZG CONDS. AT THAT TIME, THE RATE OF CLIMB WAS ABT 200'/MIN & THE GND SPD WAS 150 TO 160 KTS. AT 1032:18, A DSCNT BGN. DRG THE NEXT 2 TO 3 MIN, THE ACFT'S ALT, HDG & SPD DEVIATED. AT 1035:17, OTR PRIMARY RADAR TARGETS APPEARED, THEN RADAR CTC WAS LOST. GROSS WT OF THE ACFT WAS ESTD TO BE 4311 LBS; MAX ALLOWABLE WT WAS 4100 LBS. CG WAS ESTD TO BE 1.59 INCHES BHND THE AFT LMT. (SEE: NTSB/SIR-92/03)