DRG AN IFR FLT AT 8000' MSL IN IMC CONDS, THE PLT WAS CLEARED BY ATC TO DSCND & MAINT 4000'. HE ACKNOWLEGED. APRX 2 MIN LATER, HE WAS ADZD THAT RADAR SVC WAS TERMINATED & WAS TOLD TO CONTACT APCH CONTROL ON ANOTHER FREQ. THE PLT'S ACKNOWLEDGEMENT WAS UNINTELLIGIBLE. SUBSEQUENTLY, CONTACT WITH THE ACFT WAS LOST & IT CRASHED IN A STEEP DSCNT. BEFORE THE ACDNT, A WITNESS HEARD THE ACFT CIRCLING OVERHEAD. INITIALLY, HE WAS UNABLE TO SEE THE ACFT DUE TO CLOUDS, THEN HE SAW THE ACFT COME OUT OF THE CLOUDS IN A STEEP DIVE. HE SAID THE NOSE OF THE ACFT APPEARED TO PULL UP JUST BEFORE IMPACT. RADAR DATA SHOWED THAT THE ACFT WAS IN A SPIRALING DSCNT BEFORE IT CRASHED. THE PLT HAD JUST RCVD AN INSTRUMENT RATING ON 9/20/89. THIS WAS HIS 1ST KNOWN FLT IN ACTUAL INSTRUMENT CONDS SINCE HE HAD RCVD HIS NEW RATING. NO PREIMPACT PART FAILURE OR MALFUNCTION OF THE ACFT WAS FOUND, ALTHOUGH IT WAS BADLY DAMAGED BY IMPACT.