THE TOP OF SBP'S CLASS D AIRSPACE IS 2700 FT. THE DSCNT TO 2500 FT FOR A PATTERN ENTRY WAS NOT IN COMPLIANCE WITHOUT BEING IN CONTACT WITH TWR. ONCE THE RPTR MADE CONTACT AND BECAME REORIENTED AS TO HIS POSITION; HIS HEADS UP TO TWR OF HIS CORRECT POSITION WAS TIMELY. THERE IS SOME QUESTION AS TO WHY ARTCC DID NOT HAND THE ACFT OFF TO TWR SINCE IT WAS ON AN IFR FLIGHT PLAN. IF THE IFR FLT PLAN HAD BEEN RETAINED WITHOUT THE VISUAL APPROACH; THINGS MAY HAVE BEEN SMOOTHER FOR ALL CONCERNED.

Narrative

I HAD BEEN CLRED BY CTR TO CONDUCT A VISUAL APCH AND TOLD TO CONTACT TWR DURING AN IFR FLT. ALT WAS 5000 FT MSL 7 MI OUT ON A HDG FOR AN EXTENDED R BASE. ARPT WAS IN SIGHT (ELEVATION = 209 FT). I INITIATED A DSCNT AND BECAME PREOCCUPIED WITH MAKING BOTH A RAPID DSCNT AND AVOIDING A COUPLE VERY SMALL CLOUDS JUST ABOVE A RIDGE LINE AT 4000 FT MSL. IN ADDITION; TWR FREQ WAS CONGESTED. I FINALLY MADE CONTACT AND RPTED THAT I WAS ABOUT 5 MI OUT DSNDING ON AN EXTENDED R BASE. I WAS INSTRUCTED TO RPT R BASE. I THEN HEARD ATC TALKING TO AN AIRPLANE ON FINAL. SINCE I WAS ALREADY APCHING AN EXTENDED FINAL; I REALIZED MY INITIAL DISTANCE RPT HAD BEEN IN ERROR. I PROMPTLY RPTED TO ATC THAT I WAS ON R BASE NEAR FINAL WITH THE AIRPLANE BELOW AND IN FRONT IN SIGHT. ATC ASKED IF I WAS THE ACFT HIGH ON FINAL. I REPLIED YES. ATC INSTRUCTED ME TO MAKE A WIDE R 360 DEG TURN FOR SEQUENCING AFTER WHICH A NORMAL LNDG WAS MADE. I THINK SEVERAL THINGS CONTRIBUTED HERE. FIRST; I INADVERTENTLY MISJUDGED THE DISTANCE RPTED DURING MY INITIAL CALL-UP. SECOND; FREQ CONGESTION AND FLT DUTIES DELAYED CONTACT WITH TWR. THIRD; I SHOULD HAVE TURNED AWAY FROM CLASS D AIRSPACE TO GIVE MORE TIME TO CONTACT TWR AND CONDUCT THE DSCNT. (CTR HAD KEPT ME HIGH DUE TO TERRAIN).