AA-5B PLT EXPERIENCES SIGNAL LOSS AND SCAN BREAKDOWN ON ILS APCH.

Narrative

WX BRIEFING INDICATED LIGHT RIME IN CLOUDS AT 1600 FT MSL AND PIREP OF TOPS 3200 FT MSL. ON DEP FROM M54; I QUICKLY CLBED THROUGH THE CLOUD LAYER TO ASSIGNED ALT OF 400 FT MSL. I DEPARTED RWY 1 AND FLEW A CLBING L TURN TO 230 DEG HDG. I HAD ENGAGED THE HDG MODE OF THE AUTOPLT SHORTLY AFTER DEP AND MONITORED IT AS IT PERFORMED A STANDARD RATE TURN DURING CLB AND ROLLED OUT ON 230 DEGS. I WAS ASSIGNED THE ILS FOR RWY 2C; WHICH I PUT INTO NAV #1; WHICH IS EQUIPPED WITH AN HSI AND COUPLED WITH AUTOPLT. I LEFT NAV #2 SET ON 114.1. I WAS GIVEN A 290 DEG VECTOR AND 2500 FT ALT ASSIGNMENT AND THEN 350 DEG VECTOR TO INTERCEPT THE LOC. THE AUTOPLT SEEMED TO BE CAUSING THE PLANE TO MAKE GOOD STANDARD RATE TURNS AS I CONTINUED TO MONITOR IT. THEN EVERYTHING SEEMED TO FALL APART AT ONCE. THE HSI AND LOC SIGNAL LOST COM AND FLAGGED -- I DIALED THE NAV #2 SETTING TO THE LOC SINCE IT ALSO HAS A GS. AT THE SAME TIME; I HAD JUST CHANGED OVER TO THE TWR FREQ WHEN I NOTICED MY ATTITUDE INDICATOR AND TURN COORDINATOR INDICATING A STEEP L TURN. I CALLED A MISSED APCH. UNUSUAL ATTITUDE RECOVERY TRAINING PAID OFF. THE CTLR TOLD ME TO ROLL R AND LEVEL; CONFIRMING THAT I WAS INTERPING THE ATTITUDE INDICATOR AND TURN COORDINATOR CORRECTLY. WHILE EVERYTHING HAPPENED SO FAST; THIS INCIDENT CONFIRMS THE IMPORTANCE OF THE SCAN AND THE DIFFERENCE BTWN SIMULATED IMC AND ACTUAL. WHEN I GOT THE ACFT BACK UNDER CTL; ATC ACCOMMODATED A NEEDED CLBOUT OF THE CLOUDS (AND ICING) TO WARMER CONDITIONS. WHILE ICING MIGHT HAVE CAUSED LOSS OF NAV #1 RECEPTION AT BNA; I RETURNED TO M54 VIA THE VOR DME APCH; AND TRACKED BOTH VOR'S INTO THE ARPT WITH CEILINGS HIGH ENOUGH TO CIRCLE TO LAND. I PLAN TO GET MORE 2 PLT ACTUAL IMC IN THIS ACFT BEFORE ATTEMPTING ACTUAL IMC APCHS AT A MULTI-RWY ARPT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT HE WAS USING THE HDG SELECT FEATURE OF THE AUTOPLT; BUT DISENGAGED IT WHEN HE LOST NAV #1 RECEPTION. RPTR ADVISED THAT HIS SCAN BROKE DOWN WHEN HE WAS RETUNING THE COM AND NAV FREQS. WHEN THE CTLR ADVISED HIM TO 'ROLL R AND LEVEL;' RPTR STATED THAT HE HAD TURNED A FULL 360 DEGS TO THE L; BUT HADN'T LOST MUCH ALT. ACCORDING TO THE RPTR; THE #1 NAV RECEIVER HAD BEEN HAVING PROBS.