DRG ARR, DULLES APCH CTL (IAD) CLRD FLT TO FREDERICK TVOR (FDK) AT 4000' & TRMTD RADAR CTL WITH HANDOFF TO BALTIMORE APCH CTL (BWI). FLT WAS CLRD FOR ILS RWY 23 APCH & TOLD TO RPRT IBND ON APCH. PROC FOR APCH WAS TO FLY OBND ON FDK 048 DEG RADIAL TO RICKE INT/OM, MAKE PROC TURN (MIN ALT 2300'), RTRN TO OM ON ILS COURSE (HDG 229 DEG, MIN ALT 1600') & INTERCEPT GLIDE PATH. HOWEVER, FLT DEPD FDK ON NORTHERLY & SOMEWHAT ERRATIC COURSE. BWI DID NOT HAVE POSITIVE RADAR CTC (RCVD ONLY 2 RTRNS DRG ARR & NO RTRNS BLO 3800'). ABEAM RICKE INT/OM, ACFT MNVRD (AS IF IN A PROC TURN). AS IT WAS TURNING BACK TWD FDK, PLT RPRTD 'PROC TURN IBND, RWY 23' & WAS CLRD TO ADZY FREQ (NO FURTHER RDO CTC WITH ACFT). ACFT THEN TURNED WEST. AFTER MNVRG ABT 8 MIN, IT HIT MTS ABT 7 MI NW OF ARPT (ELEV 1700') ON HDG TWD FDK. IAD HAD RADAR CTC &MIN SAFE ALT WARNING (MSAW) OCCURRED BFR ACDNT. IAD CTLR DIDN'T TRY ALERTING BWI OR PLT, BUT MSAW WAS AFTER PLT WAS CLRDTO ADZY FREQ. CANCELED NOTAM STILL ISSUED AS ACTIVE, BUT FDK WAS PLT'S HOME BASE.