PLT OF AN SMA SEL FAILED TO FOLLOW ASSIGNED FLT PLAN RTE AND WAS VECTORED BY ATC ON COURSE.

Narrative

AT XA20 UTC I DEPARTED N88 ON AN IFR FLT PLAN TO LANCASTER; PA. I DEPARTED RWY 05; SWINGING WIDE TO THE W. AS I STABILIZED FLT; I ACTIVATED AUTOPLT. I INADVERTENTLY REMOVED HDG AND NAV FLT MODES FROM THE FLT CTL SYS. WHEN I REALIZED THIS; I ACTIVATED HDG MODE BUT BY THIS TIME I WAS N OF COURSE AND DIDN'T REALIZE IT UNTIL PHL APCH TOLD ME. I ACCEPTED A 220 DEG L TURN TO INTERCEPT V143 WHICH I PROPERLY INTERCEPTED (HAND FLYING THE INTERCEPT). MY MISTAKE WAS CHOOSING THE HDG MODE FOR THE AUTOPLT. I SHOULD EITHER HAVE CHOSEN THE NAV MODE OR TURNED THE HDG BUG TO INTERCEPT THE COURSE TO PTW VOR. I SHOULD ALSO HAVE PAID MORE ATTN TO VOR #1'S CDI. I WAS A BIT ANXIOUS SINCE THIS WAS MY FIRST SINGLE PLT FLT IN IMC. AFTER THIS; I SETTLED DOWN AND MAINTAINED MY COURSE; SAME FOR FLT BACK. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT HE HAS NOT HEARD FURTHER FROM THIS INCIDENT EVEN THOUGH THE CTLR WHO HELPED HIM WITH A VECTOR TO ON COURSE DID SOUND PERTURBED ABOUT THE INCIDENT. HE STATED THAT HE WAS REALIZING HIS MISTAKE AND CORRECTING BACK AT THE SAME TIME THAT ATC CTLR INTERVENED.