ACFT WAS OBSERVED IN A RT BANK WHEN IT EXPERIENCED AN INFLT BREAKUP. BOTH WINGS, VERT STAB AND RUDDER, AND THE HORZ STAB AND TRIM TAB SEPARATED PRIOR TO IMPACT. WX WAS DARK NIGHT WITH SCATTERED TO BROKEN CLOUD COVER, BUT VFR. ALTHOUGH A WX RPT 33 NM NORTHWEST OF THE SITE LISTED THE WX AS 10,000 SCT, 25,000 OVC, A GROUND WITNESS STATED THAT IT WAS CLOUDY, BUT THAT HE COULD SEE SOME STARS BETWEEN THE CLOUDS. THE NON-INSTRUMENT RATED PVT PLT, WHO HAD CHECKED OUT IN THE ACFT THAT DAY, HAD BEEN RESTRICTED FROM NIGHT FLIGHT DUE TO NON-COMPLIANCE WITH FAR 61.109 (MINIMUM NIGHT TIME) WHEN HE RECEIVED HIS PVT CERT. INSTRUCTOR HAD WARNED HIM NOT TO ATTEMPT TO FLY SOLO AT NIGHT. ALL SEPARATION FRACTURES WERE OVERSTRESS. RT WING WAS STRUCK BY THE LFT WING AFTER IT SEPARATED IN A NEGATIVE MANNER. PLT HAD 2 HRS DUAL NIGHT LOGGED SEVERAL MONTHS PRIOR TO THE ACCIDENT AND ABOUT 45 MINS SOLO ON THE ACCIDENT FLT.