FLT WATCH AT 1800 FT OVER THE CITY EXPERIENCES PARTIAL PWR FAILURE AND HAD TO MAKE AN OFF ARPT FORCED LNDG.

Narrative

I WAS FLYING THE TFC WATCH ACFT ALONG THE FREEWAYS. WHILE ORBITING OVER THE LOS ANGELES CONVENTION CTR; A SUDDEN DROP OF 500 RPM OCCURRED. I WAS AT 1800 FT MSL (APPROX 1200 AGL) AT THE TIME. THE CLOSEST EMER FIELD WAS THE DODGERS STADIUM PARKING LOST. I HEADED IN THAT DIRECTION; GOING THROUGH ALL EMER PROCS. THE RPM'S KEPT DROPPING TO 1500 RPM. I COULD NOT MAINTAIN ALT TO REACH AN ARPT SAFELY; AND THEREFORE MADE THE DECISION TO LAND IN THE EMPTY PARKING LOT; TO AVOID PUTTING THE LIFE OF MY PAX (THE RPTR) AND ANYBODY ON THE GND INTO DANGER. NO DAMAGE OR INJURY OCCURRED AND THE ACFT WAS TRUCKED OUT THE NEXT DAY. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: WAS AN EMER DECLARED? I WAS ON THE HELI FREQUENCY EVEN THOUGH I WAS A FIXED WING AND DID NOT ACTUALLY DECLARE AN EMER SPECIFICALLY; BUT RATHER; TOLD THEM WHAT I WAS DOING. WERE THERE ANY REPERCUSSIONS FROM THE EVENT LIKE FINES OR SUITS OR VIOLATIONS? NO. WHAT WENT WRONG WITH THE ENG? THE CAM SHAFT BEARING FAILED AND I WAS ONLY RUNNING ON 2 OR 3 OF THE 4 CYLINDERS AND GETTING ONLY 1600 RPM. WITH THE FUEL AND PAX IN THIS CESSNA 150 I WAS AT FULL GROSS. ANYTHING IN HINDSIGHT YOU WOULD DO DIFFERENTLY LOOKING BACK? NO. I CHKED THE CARB HEAT; FUEL; MIXTURE; THROTTLE; IGNITION; MAGNETOS; AND PRIMER. PERHAPS; I WOULD HAVE PLANNED MY BASE TURN A LITTLE DIFFERENTLY AS I WAS A BIT HIGH AND FAST: BUT; I WAS PRETTY LOW TO BEGIN WITH AND DIDN'T HAVE MUCH TIME.