Narrative:

Cruise phase of flight while scanning instruments, I noticed the right engine oil pressure gauge had dropped. I confirmed this with a flashlight. The needle was indicating below the green arc, yet not in the red line. I felt this could be significant and that it could have been this low for the entire duration of cruise, greater than 45 mins. I referred to the abnormal checklist without an answer as to the appropriate action. I reduced power to 50% while I referred to the aircraft manual. I again found no advice for the situation. I knew that below the green line was undesirable and less power should be used. I tried switching inverters with no change. I tried reducing power on the good engine to see how that oil pressure gauge reacted. The only corrective action I could see was to turn around back to las and land as soon as possible. I declared an emergency, asked for vectors direct, and proceeded with the precautionary engine shutdown checklist. I landed at las with no further incident, and called company maintenance. This was the first flight of the night, leg 1 of 4. I was well rested and well fed. I had been flying the BE1900 for the previous 2 weeks, and this was a last min switch to the BE99. I was rushed to get loaded and airborne, and although I scanned the 'gauges in the green' on the takeoff roll, I cannot confirm the exact reading of the oil pressure before takeoff. The airplane I had just picked up from an outside maintenance contractor for avionics work, I felt this had no bearing on the situation. I felt it was wise to secure the engine and prevent possible further damage and loss of revenue.

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Original NASA ASRS Text

Title: BE99 CREW HAD LOW OIL PRESSURE IN #2 ENG IN ZLA CLASS E AIRSPACE.

Narrative: CRUISE PHASE OF FLT WHILE SCANNING INSTS, I NOTICED THE R ENG OIL PRESSURE GAUGE HAD DROPPED. I CONFIRMED THIS WITH A FLASHLIGHT. THE NEEDLE WAS INDICATING BELOW THE GREEN ARC, YET NOT IN THE RED LINE. I FELT THIS COULD BE SIGNIFICANT AND THAT IT COULD HAVE BEEN THIS LOW FOR THE ENTIRE DURATION OF CRUISE, GREATER THAN 45 MINS. I REFERRED TO THE ABNORMAL CHKLIST WITHOUT AN ANSWER AS TO THE APPROPRIATE ACTION. I REDUCED PWR TO 50% WHILE I REFERRED TO THE ACFT MANUAL. I AGAIN FOUND NO ADVICE FOR THE SIT. I KNEW THAT BELOW THE GREEN LINE WAS UNDESIRABLE AND LESS PWR SHOULD BE USED. I TRIED SWITCHING INVERTERS WITH NO CHANGE. I TRIED REDUCING PWR ON THE GOOD ENG TO SEE HOW THAT OIL PRESSURE GAUGE REACTED. THE ONLY CORRECTIVE ACTION I COULD SEE WAS TO TURN AROUND BACK TO LAS AND LAND ASAP. I DECLARED AN EMER, ASKED FOR VECTORS DIRECT, AND PROCEEDED WITH THE PRECAUTIONARY ENG SHUTDOWN CHKLIST. I LANDED AT LAS WITH NO FURTHER INCIDENT, AND CALLED COMPANY MAINT. THIS WAS THE FIRST FLT OF THE NIGHT, LEG 1 OF 4. I WAS WELL RESTED AND WELL FED. I HAD BEEN FLYING THE BE1900 FOR THE PREVIOUS 2 WKS, AND THIS WAS A LAST MIN SWITCH TO THE BE99. I WAS RUSHED TO GET LOADED AND AIRBORNE, AND ALTHOUGH I SCANNED THE 'GAUGES IN THE GREEN' ON THE TKOF ROLL, I CANNOT CONFIRM THE EXACT READING OF THE OIL PRESSURE BEFORE TKOF. THE AIRPLANE I HAD JUST PICKED UP FROM AN OUTSIDE MAINT CONTRACTOR FOR AVIONICS WORK, I FELT THIS HAD NO BEARING ON THE SIT. I FELT IT WAS WISE TO SECURE THE ENG AND PREVENT POSSIBLE FURTHER DAMAGE AND LOSS OF REVENUE.

Data retrieved from NASA's ASRS site as of July 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.