SMA HAS GYROSCOPE FAILURE. MAKES ILS APCH WITH NO GYROSCOPE.

Narrative

DEPARTED BFA ON IFR FLT PLAN NOTICED GYROSCOPE FAILURE DUE TO LACK OF ACCURATE TRACKING OF AUTOPLT. RPTED GYROSCOPE FAILURE TO CTR. I WAS IN VFR CONDITIONS ON TOP ENRTE AND RPTED WX WAS IMPROVING TOWARDS DEST SO FLT WAS CONTINUED WITHOUT EVENT. CLOUD LAYER WAS OVERCAST - 1000 FT THICK. WAS ESTABLISHED ON ILS IN VFR CONDITIONS FOR LETDOWN. I WAS SWITCHED TO TWR FREQ DURING DSCNT; I WAS APPROX 1/2 MI S OF LOC - HAD FULL SCALE DEFLECTION ON ILS BUT AS I KNEW I WOULD BE VFR IN 100-200 FT WELL ABOVE TERRAIN AND MDA CONTINUED APCH WITH A CORRECTION TO N. BROKE OUT ABOUT 500 FT ABOVE MDA/DH ON 2 MI FINAL. TWR INFORMED ME APCH HAD CALLED THEM TO SAY I WAS OFF ILS. TOLD TWR I WAS VFR NOW AND HAD GYROSCOPE FAILURE TO EXPLAIN DEV FROM COURSE AND NOT MISSING APCH. MY LAST PRACTICE WITH PARTIAL PANEL WAS ABOUT 1 1/2 YRS AGO AT TIME OF WINGS PHASE I PROGRAM. ALTHOUGH DIRECTIONAL GYROSCOPE AND VACUUM PUMP WERE LESS THAN A YR OLD AND PLANE HAS STANDBY VACUUM SYS; PARTIAL PANEL PRACTICE NEEDS TO BE DONE MORE FREQUENTLY.