JET ACFT HAS R ROLL MOTION WHENEVER AUTOPLT ENGAGED.

Narrative

WE TOOK OFF FROM SNA CLRED TO 5000 FT. AFTER COMPLETING THE SNA NOISE ABATEMENT PROC AT 5 DME FROM THE RWY 19R LOC; WE BEGAN A NORMAL CLB TO OUR PREVIOUSLY CLRED ALT OF 13000 FT. I SET CLB PITCH AND ENGAGED THE AUTOPLT. ACFT ROLLED HARD TO THE R. DISENGAGED AUTOPLT AND REGAINED NORMAL FLT ATTITUDE. RE-ADJUSTED PLT'S HDG BUG AND TRIED AUTOPLT AGAIN WITH SAME RESULTS. RE-SLAVED PLT'S COMPASS AND MADE SEVERAL MORE ATTEMPTS TO ENGAGE AUTOPLT WITH THE SAME RESULTS. FINALLY SHIELDED MY EYES FROM THE SETTING SUN TO GET A CLR LOOK AT THE AUTOPLT CTL HEAD BTWN THE PLT SEATS AND DISCOVERED THE ROLL KNOB IN THE FULL R POS. SINCE WE NEVER USE THE ROLL KNOB; I NEVER SUSPECTED IT. WITH SEVERAL PEOPLE IN AND OUT OF THE AIRPLANE; IT MUST HAVE BEEN ACCIDENTALLY KICKED. WITH NO PAX ABOARD WE BECAME OVER ZEALOUS IN TRYING TO FIGURE OUT THE PROB; LEADING TO SOME VERY ERRATIC LOOKING FLYING. THE COMBINATION OF AN ABNORMAL KNOB POS ON THE AUTOPLT AND LIMITED VISION WITH THE SUN IN OUR EYES LED TO US GETTING DISTRACTED. WE WROTE THE AUTOPLT UP FOR EXCESSIVE ROLL RATE AND WILL INCLUDE THE ROLL KNOB POS ON OUR TAXI CHKS FROM NOW ON.