AN SMA FLYING IN DEN; CO; AIRSPACE IS UNCERTAIN OF THE LOCATION OF CLASS B AIRSPACE. PLT FEELS THERE MIGHT HAVE BEEN AN INTRUSION.

Narrative

I WAS OVER THE TOWN OF MONUMENT; CO; AT 10500 FT MSL AFTER HAVING FLOWN AROUND OVER THE HILLS TO THE W. I SET UP FOR A CRUISE DSCNT BACK TO MY BASE AT CENTENNIAL ARPT; TUNED; IDENTED; AND TURNED TOWARD THE CASSE NDB; AND THEN TUNED IN AND NOTED CENTENNIAL'S ATIS. A FEW MI S OF CASTLE ROCK; AT 10000 FT MSL AND A LITTLE E OF I25 (THE MAIN HWY); I GLANCED AT THE DEN TERMINAL CHART TO SEE WHERE THE CLASS B BEGAN; AND WAS HORRIFIED TO SEE THAT I WAS CLOSE TO PENETRATING THAT AIRSPACE; IF I HAD NOT DONE SO ALREADY. I HAD SOMEHOW THOUGHT THAT THE BOUNDARY WAS N OF CASTLE ROCK. I PULLED THE THROTTLE ALL THE WAY BACK AND BEGAN A 1000 FPM DSNDING L TURN BACK TO THE S. WHEN I WAS DOWN TO 8500 FT MSL; I TURNED BACK TO THE N AND CONTINUED TOWARD CENTENNIAL. AS I ARRIVED OVER THE POINT WHERE I HAD FIRST NOTICED THE POSSIBLE INCURSION; I NOTED THAT THE LORAN; WHICH IS NOT VERY ACCURATE; INDICATED THAT I WAS 18.3 MI FROM CENTENNIAL. ON MY DEN TERMINAL CHART I MEASURED THE DISTANCE FROM CENTENNIAL TO THE EDGE OF THE CLASS B (IN THE DIRECTION OF CASTLE ROCK) TO BE ROUGHLY 13 MI; AND THE DISTANCE FROM CENTENNIAL TO THE POINT WHERE I THINK I TURNED AROUND TO BE ROUGHLY 15 MI. IF I'M RIGHT; THEN NO INCURSION TOOK PLACE. IF I'M WRONG.... I SHOULD HAVE CONTINUED CIRCLING OVER MONUMENT UNTIL I HAD FORMULATED A COMPLETE PLAN FOR THE RETURN TO BASE. I DID FEEL A LITTLE PRESSURE FROM 1 OF MY PAX; WHO WANTED TO GET BACK IN TIME FOR A DINNER ENGAGEMENT. WHETHER OR NOT AN INCURSION TOOK PLACE; I DO FEEL THAT I SCREWED UP IN NOT HAVING PROPER SITUATIONAL AWARENESS REGARDING THE LOCATION OF THE CLASS B. IN THE FUTURE; WHENEVER I AM READY TO HEAD BACK TOWARD THE CLASS B; I WILL TAKE THE EXTRA TIME TO REVIEW CLASS B PARTICULARS BEFORE HDG BACK.