THE ACFT WAS CLEARED FOR AN ILS RWY 4 APCH WHILE 9 MILES NORTH OF OTH (NORTH BEND) VOR. INSTRUCTIONS WERE GIVEN TO CROSS OTH VOR AT OR ABOVE 3700 FT MSL. 14 MIN LATER, THE PLT REPORTED TO NORTH BEND FSS 'MY NEEDLE DOESN'T SEEM TO BE MOVING ON MY LOCALIZER HERE UH YOU KNOW MY LOCATION.' INDICATIONS OF NAV/COM DIFFICULTIES CONTINUED. ACFT WAS CLEAREDBY ARTCC TO DESCEND FROM 5000 FT TO 3000 FT HEADING 360 DEGS WHILE 11 MILES SW OF ARPT. AFTER A HEADING CHANGE TO 035 DEG, THE PLT STATED 'I GOT IT CENTERED NOW'. AT THE OUTER MARKER HE SAID 'I'M A LITTLE HIGHER TWO THOUSAND I'LL TRY TO GET DOWN.' ARPX 2 MIN LATER, THE PLT REPORTED AN ALT OF 800 FT. THE ACFT CRASHED IN A HILLY WOODED AREA APRX 3 MI NNE OF THE ARPT. A CHIEF PLT & AN FAA EXAMINER REPORTED THE PLT'S IFR PERFORMANCE WAS UNSATISFACTORY IN A PART 135 CHECKRIDE. ACCORDING TO ANOTHER PLT AND MAINTENANCE RECORDS, N1067U HAD A HISTORY OF DISCREPANCIES WITH THE NAV EQUIP. A COMPANY PLT STATED THE COMPANY PUT PRESSURE ON THE PLTS TO FLY ACFT WHICH SOMETIMES WERE NOT AIRWORTHY.