ENG SHUTDOWN AND RETURN LAND BECAUSE OF LOW OIL PRESSURE. OIL DIPSTICK WAS MISSING.

Narrative

I ARRIVED AT THE ARPT 1 HR PRIOR TO DEP TO STOCK THE ACFT AND COMPLETE A PREFLT INSPECTION. ON INSPECTION; I NOTED THE L AS WELL AS THE R ENG WERE 1 QUART LOW ON OIL. I PROCEEDED TO ADD OIL TO THE L ENG THEN THE R SIDE. BEFORE OIL WAS ADDED TO THE R ENG; I REMOVED THE DIPSTICK AND PLACED IT ON THE R WING NEAR THE SPD BRAKE. AFTER ADDING THE OIL I BECAME DISTR BY CONVERSATION WITH THE ACFT FUELER. THINKING I HAD REPLACED THE DIPSTICK; I SECURED THE OIL COVER ON THE NACELLE AND MOVED TO OTHER THINGS. I HAD COMPLETED A WALKAROUND PRIOR TO CHKING THE OIL. A FINAL WALKAROUND BEFORE BOARDING THE ACFT WAS APPARENTLY NOT COMPLETE ENOUGH. I WAS THE FO ON THE FLT AS WELL AS THE PF ON THIS LEG. EVERYTHING WAS NORMAL ON TAXI; TKOF; AND CLB. AS WE CLBED THROUGH FL200 A MASTER WARNING ANNUNCIATOR ILLUMINATED. A DROP IN OIL PRESSURE WAS OBSERVED AND A PRECAUTIONARY SHUTDOWN OF THE R ENG WAS COMPLETED. WE DECLARED AN EMER AND PROCEEDED DIRECTLY BACK TO CLL. DSCNT AND LNDG WERE UNEVENTFUL AND WE TAXIED BACK TO OUR HANGAR WITHOUT INCIDENT. ON INSPECTION IT WAS FOUND THAT THE R DIPSTICK WAS MISSING CAUSING A LOSS OF OIL PRESSURE AT ALT. THE CAUSE OF THIS INCIDENT WAS A LACK OF A THOROUGH FINAL PREFLT WALKAROUND. ON EVALUATION OF THE EVENTS LEADING UP TO THIS INCIDENT; STEPS HAVE BEEN TAKEN TO INSURE THIS DOES NOT HAPPEN AGAIN. THEY ARE: 1) ALWAYS COMPLETE A FINAL WALKAROUND ON THE ACFT. 2) DOUBLECHK ALL CAPS TO MAKE SURE THEY ARE SECURE. 3) NEVER GET IN A HURRY WITH PREFLT OF ACFT. 4) STAY FOCUSED ON TASK AT HAND. 5) DO NOT LET OUTSIDE ENVIRONMENT DISTRACT FROM PREFLT.