C501 PLT ENCOUNTERED MODERATE TURB AND HVY RAIN FROM TSTM.

Narrative

DURING TAXI I PERFORMED THE AUTOPLT TEST FOLLOWED BY THE ELECTRIC TRIM TEST; BOTH OF WHICH WERE COMPLETED NORMALLY. ON DEP (VMC) I ATTEMPTED TO ENGAGE THE AUTOPLT; BUT ONLY THE YAW DAMPER WOULD ENGAGE. I BRIEFLY THOUGHT ABOUT TURNING AROUND AND LNDG AGAIN -- WHICH WOULD HAVE BEEN THE CORRECT AND CONSERVATIVE DECISION. HOWEVER; I DECIDED TO PRESS ON; AND NEXT WAS CONFRONTED BY HAVING TO MANEUVER AROUND SOME WX. APCH CLRED ME TO DEVIATE AS NEEDED; BUT THE PATH DIRECTLY AHEAD LOOKED GOOD ON MY ONBOARD RADAR; A SWATH OF GREEN BTWN RED ON MY R AND L. I MENTIONED THIS TO ATC; WHO SAID EVERYONE ELSE HAD BEEN DEVIATING; BUT I DECIDED IT WAS OK AHEAD. IN FACT IT WAS; BUT WE DID ENCOUNTER SOME BRIEF HVY RAIN AND SOME INTERMITTENT MODERATE TURB. WE SAW NO NEARBY LIGHTING; WITH THE NEAREST BEING PERHAPS 10 MI ON MY L. BUT WHAT WAS I THINKING? IF I HADN'T BEEN TRYING TO GET THE AUTOPLT BACK ON LINE; I PROBABLY WOULD HAVE DEVIATED AROUND THE AREA ANYWAY. THERE WAS REALLY NO REASON NOT TO; AND TO BE HONEST; IT WAS SIGNIFICANTLY WORSE THAN I WOULD HAVE THOUGHT BASED ON THE IMAGE PAINTED ON MY RADAR; AND A TURN TO THE R WOULD HAVE PUT ME IN NEAR VMC. ON CLBOUT PASSING ABOUT FL200 IN VMC; THE AUTOPLT STARTED TO WORK AGAIN; AND WORKED FLAWLESSLY THE REST OF THE FLT. LESSONS: 1) ALTHOUGH PROBABLY LEGAL; IT WAS A VERY POOR DECISION NOT TO IMMEDIATELY RETURN TO THE DEP ARPT TO CORRECT THE AUTOPLT PROB (THIS WAS LATER DEMONSTRATED TO BE A REPEATABLE; AND DUE TO A DIRTY RELAY); 2) I NEED BETTER/RECURRENT INSTRUCTION IN INTERP OF ONBOARD RADAR. I'M USED TO FLYING WITH NOT ONLY RADAR; BUT ALSO WITH A LIGHTNING DETECTOR AS WELL AS UP-LINKED 'NEXRAD' IMAGES ON A WX RADAR SYS; AND I THINK THAT MY BASIC RADAR SKILLS HAVE DETERIORATED. I'M GOING TO DIG OUT THE WX RADAR TRAINING TAPES AGAIN BEFORE MY NEXT FLT.