THE PLT REPORTED A LOSS OF POWER ON BOTH ENGS DURING DESCENT TO LAND. APRX 3 MINS PRIOR, TWR GAVE PLT OPTION OF 'STRAIGHT-IN' TO RWY 14 OR REG PATTERN TO RWY 32. THE PLT HESITATED & SAID 'JUST A MINUTE' & TWR OFFERED WIND INFO AS '210 AT 13.' PLT REPLIED, 'KAY.' APRX 1 MIN LATER PLT SAID '33W WILL MAKE A LEFT BASE FOR 14.' TWR CLEARED HIM & DECLARED VISUAL CONTACT. PLT ACKNOWLEDGED '3WHISKEY.' ONE MIN & 54 SECS LATER, PLT DECLARED PWR LOSS & EMERG. TWR ROGERED. SEVEN SECS LATER, PLT SAID 'GONNA HIT IT' FOLLOWED 2 SECS LATER WITH AN UNITELLIGIBLE COMMENT. WITNESSES SAW THE ACFT GLIDING WINGS LVL TOWARD RWY WHEN A LOUD 'REV' WAS HEARD, THE ACFT PITCHED UP & ROLLED LEFT TO AN INVERTED POSITION BEFORE GROUND CONTACT & EXPLOSION. POST ACCIDENT INVESTIGATION DID NOT DISCLOSE ANY ENG OR FUEL SYSTEM MALFUNCTION. THIS ACFT HAD EXPERIENCED A PWR LOSS AFTER DESCENDING FROM 15500 TO 12000 FT MSL ON 2/2/85 WITH THE SAME PLT AS REPORTED BY THE CO-PLT ON THAT FLT. AFTER APRX 1 1/2 MINUTES PWR WAS RESTORED.