RPTR EXPERIENCED DUAL NAV FAILURE WHILE FLYING LOC APCH; EXECUTED A MISSED APCH; AND DEVIATED FROM PUBLISHED IAP ALT ON MISSED APCH.

Narrative

WHILE ENRTE TO GNV MY PRIMARY NAV RADIO BECAME INOP. I NOTIFIED CTR OF LOSS AND THAT I WAS ON BACKUP VOR. AFTER BEING CLRED FOR THE APCH AND PASSING FAF; MY SECONDARY NAV WENT OUT AND I CALLED A MISSED APCH. DURING THE MISSED APCH; I WAS TRYING TO CORRECT THE RADIO PROB AND FAILED TO MONITOR THE ALTIMETER. I ONLY MADE SURE THAT I WAS CLBING AT AN ACCEPTABLE AIRSPD AND ON THE APPROX CORRECT HDG. WHEN CTR ASKED ABOUT ALT; I MADE CORRECTIONS FROM 2700 FT TO 2000 FT. A FEW MIN LATER INFORMED CTLR THE REASON FOR MISSED APCH. I WAS ABLE TO GET THE #2 OP AND TOLD THE CTLR THAT I WOULD LIKE TO TRY ANOTHER APCH. IF WAS UNSUCCESSFUL I WOULD DEV TO MY ALTERNATE JAX FOR AN ASR APCH. DURING THE SECOND APCH THE NAV AGAIN WENT OUT. I WAS WITHIN 200-300 FT OF BREAKING OUT OF THE CLOUDS SO I CHOSE TO CONTINUE THE APCH. I BROKE OUT OFF CTR OF RWY BUT PARALLEL AND WAS CLRED BY TWR TO CIRCLE AND LAND RWY 10. THE CHAIN OF EVENTS THAT LED TO THIS SIT STARTED WITH THE FAILURE OF MY PRIMARY NAV INST. I HAD LITTLE EXPERIENCE SHOOTING UNFAMILIAR APCHS USING A SINGLE VOR. WHEN THE SECOND NAV FAILED; I FELT CERTAIN THAT I HAD A DISTRESS SIT; IF NOT AN EMER. I WAS MORE CONCERNED ABOUT ACFT CTL; INOP EQUIP; AND MINIMUM ALT FOR THE MISSED APCH. IN RETROSPECT THIS WAS NOT THE PROPER DECISION. ALTHOUGH MY PRIMARY NAV IS LESS THAN 6 MONTHS OLD; I PLAN TO HAVE IT CHKED COMPLETELY AND CONSIDER UPGRADING MY SECOND NAV TO STATE-OF-THE-ART EQUIP. THIS TYPE SIT COULD BE DUPLICATED AND INCLUDED IN PRACTICE SESSIONS IN VFR CONDITIONS.