AN SMA PLT DSNDED BELOW HIS ASSIGNED ALT WHILE PROGRAMMING HIS ADVANCED ELECTRONIC NAV SYSTEM WITH GPS SELECTED.

Narrative

AT 3000 FT CLRNC TO 2100 FT; NAV GPS (NEW GARMIN 430) WHILE ON DSCNT AND RADAR VECTORS; WENT TO GARMIN 430 TO PUT IN APCH. SINCE THIS UNIT WAS NEW TO ME IT WAS NOT DOING WHAT I THOUGHT IT WAS SUPPOSED TO. IT TOOK MY ATTENTION AWAY TOO LONG AND APCH ADVISED CHECK MY ALT; AND I WAS AT 1700 FT NOT AT 2100 FT. I QUICKLY CLBED BACK TO 2100 FT AND LEFT THE 430 GO AND FLEW THE ACFT WITH NO FURTHER EVENTS. I PROBABLY NEED MUCH MORE TRAINING ON THE GARMIN 430 BEFORE NEXT IFR FLT. MOST OF MY FLYING IS IN CORPORATE JETS WITH TWO PLTS AND AN AUTOPLT THAT WHEN ARMED; WILL LEVEL THE ACFT OFF. I WAS USING THE AUTOPLT IN THE ACFT WHICH DOES NOT HAVE AUTO LEVELOFF OR CAPTURE ALT. YOU CAN PRACTICE A LOT WITH THE CD ON A COMPUTER; BUT IT IS NOT LIKE WHEN YOU ARE FLYING WITH OTHER DUTIES. SIMPLY PUT; I WAS HAVING TUNNEL VISION FOCUS ON WHAT THE GARMIN 430 WAS DOING AND NOT DOING AND NOT PAYING ATTENTION TO FLYING AND THE DSCNT TO A NEW ALT. I SHOULD HAVE WAITED UNTIL I LEVELED OFF; PUT ALT HOLD ON; AND THEN WORKED ON SETTING UP THE 430 FOR THE APCH. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: PLT STATED THAT HE HAD FLOWN THE SYSTEM ONCE PRIOR TO THIS ON A CERTIFICATION FLT. ON THIS FLT HE DID NOT HAVE THE APCH SET UP PRIOR TO BEING GIVEN VECTORS AND WHEN GIVEN VECTORS FOR A SPECIFIC RWY APCH; HE COULD NOT FIND THE APCH ON THE MENU WHERE HE THOUGHT THEY SHOULD BE AVAILABLE. HIS PERCEPTION WAS THAT HE LOOKED AWAY FOR ONLY A FEW SECONDS; BUT THE TIME INTERVAL MUST HAVE BEEN MUCH MORE. SINCE THIS INCIDENT; RPTR STATED THAT HE HAS SPENT ABOUT 30 HRS ON THE GARMIN 430 CD SIMULATOR. RPTR FEELS THE SIMULATOR IS NOT LIKE THE ACTUAL ACFT AND THAT FLT TRAINING WITH THE GARMIN SYSTEM AND IN INSTRUCTOR SHOULD BE MANDATORY. THE PLT MOSTLY FLIES AN OLDER HAWKER ACFT. THAT ACFT HAS AN FMS BUT DOES NOT HAVE A MOVING MAP LIKE HIS GARMIN 430. THE MAP ADDED A LEVEL OF SOPHISTICATION THAT CAN LEAD TO DISTRACTION AND CONFUSION FOR THE UNTRAINED.