PA28 PLT HAD ALT OVERSHOOT AFTER BEING DISTR CHANGING GPS PROGRAMMING IN ZAU CLASS E AIRSPACE.

Narrative

I WAS CLRED IN AN IFR CLB TO 12000 FT; AND WAS CLBING WITH THE AUTOPLT IN 'ALT' AND NAV MODE. THE NAV INPUT WAS A GPS ON A DIRECT FLT FROM TEW TO UMP. THE CLB RATE WAS CLOSE TO 1000 FPM. AT ABOUT 11500 FT; ZAU GAVE ME A NEW (AN UNUSUAL) CLRNC TO JOIN V116; FLY DIRECT TO AN INTXN; THEN CONTINUE DIRECT TO UMP. I DIDN'T KNOW WHERE V116 WAS; NOR THE INTXN; BUT FOUND BOTH FAIRLY QUICKLY ON THE CHART. NEXT; I STARTED REPROGRAMMING THE GPS TO INTERCEPT AND JOIN THE AIRWAY AND FLY TO THE INTXN. THIS TOOK SOME TIME AND FOOLING WITH THE GPS; PARTLY BECAUSE IT WASN'T CLR WHETHER I WAS ALREADY PAST V116 OR HAD IT AHEAD. I FINALLY JUST TURNED W ON AN ESTIMATED INTERCEPT; NOTICED I WAS ALREADY AT 12500 FT; AND STARTED A RAPID DSCNT. ABOUT THAT TIME THE CTLR CALLED WITH A 'XXXX VERIFY ALT' CALL. I LEVELED AT 12000 FT AND CALLED THE CTLR 'LEVEL AT 12000 FT.' THE CTLR SAID NO MORE; AND CONTINUED TO ISSUE MORE VECTORS; WITH WHICH I COMPLIED WITHOUT FURTHER PROBS. CONTRIBUTING FACTORS: NOT KNOWING THE GPS: I HAVE FLOWN WITH THE GPS FOR 9 MONTHS AND THOUGHT I KNEW IT PRETTY WELL; BUT MOST OPS ARE DIRECT POINT-TO-POINT AND APCHS. WHEN I DO (RARELY) FLY AIRWAYS; I SET UP A 'RTE' THAT IS VOR TO INTXN TO VOR; ETC. IT WAS NOT IMMEDIATELY CLR TO ME HOW TO SET THE GPS UP TO INTERCEPT THE AIRWAY AND FLY TO THE INTXN. ALLOWING MY ATTN TO BE DIVERTED TOO LONG: I REALIZE IT'S A BASIC TENANT TO KEEP WATCHING THINGS. THIS WAS A MOMENTARY LAPSE IN THAT VIGILANCE FOR REASONS I CAN'T EXPLAIN. A COURSE CHANGE TO THE W AT THAT POINT IS UNUSUAL. THE NEW COURSE PATH WAS 90 DEGS TO MY THEN PRESENT COURSE. IN ADDITION; THE WINDS WERE VERY STRONG SO THE NEW HDG WAS ABOUT 220 DEGS EVEN THOUGH THE COURSE WAS ABOUT 270 DEGS. CORRECTIVE ACTIONS: AN IFR GPS IS A WONDERFUL TOOL; BUT BY ITS NATURE; IT'S COMPLEX. SOME INFREQUENTLY USED OPS TAKE A WHILE TO FIGURE OUT; BUT IN AN IFR ENVIRONMENT; THE LUXURY OF TIME IS OFTEN NOT AVAILABLE. PROBABLY THE BEST CORRECTIVE ACTION IS SOME DRILLING WITH THE GPS IN SITS THAT ARE OUT OF THE NORM FOR GPS OPS. IN ADDITION; I THINK I TEND TO USE THE GPS FOR ALL NAV FUNCTIONS; AND THAT'S CLRLY NOT A GOOD IDEA. THE GPS DOES SO MUCH THAT IT BECOMES A CTR OF FOCUS. THIS GPS SHARES THE AUTOPLT INPUT AND PRIMARY NAV HEAD WITH AN RNAV. I SHOULD HAVE DESELECTED THE GPS; TUNED IN JXN; SET THE RADIAL; AND PERFORMED A NORMAL INTERCEPT WITH THE VOR. I KNOW HOW TO DO THIS ALMOST WITHOUT THINKING. THIS WOULD HAVE TAKEN A LOT LESS TIME AND DIVERTED MY ATTN ONLY BRIEFLY. NEXT; I COULD HAVE FOUND THE INTXN; AND FLOWN TO IT AS USUAL (I THINK IT HAD A DME FIX). ALTERNATIVELY; USING THE GPS; I COULD HAVE ENTERED 'DIRECT JXN;' SWITCHED TO OBS MODE; ENTERED THE OUTBOUND RADIAL; AND INTERCEPTED AS NORMAL. SEEMS SIMPLE NOW; BUT NOT AT THE TIME. THIS PROBABLY WOULD HAVE BEEN THE BEST ACTION. I THINK THE POINT IS THE NEW COCKPIT SYS ARE EXTREMELY FLEXIBLE AND USEFUL; BUT FLEXIBILITY IMPLIES THE NEED TO PROGRAM THE SYS FOR THAT SIT. THE PROGRAMMING USUALLY HAS TO HAPPEN QUICKLY; AND IF IT'S A NEW SIT; THAT MAY REQUIRE A LITTLE THOUGHT. THAT TAKES TIME; BUT IN THE MEANTIME; THE ACFT STILL REQUIRES ATTN.