Commuter aircraft has oil pressure fluctuation, then warning light. Engine shutdown. Return land.

Attributes
ACN	195327
Time
Date	199111
Day	Mon
Local Time Of Day	0601 To 1200
Place
Locale Reference	atc facility : cle airport : zob
State Reference	OH
Altitude	msl bound lower : 21000 msl bound upper : 21000
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Controlling Facilities	artcc : zob
Operator	common carrier : air carrier
Make Model Name	Light Transport, Low Wing, 2 Turboprop Eng
Navigation In Use	Other Other
Flight Phase	cruise other
Route In Use	enroute : on vectors
Flight Plan	IFR
Person 1
Affiliation	company : air carrier
Function	flight crew : captain oversight : pic
Qualification	pilot : atp pilot : instrument
Experience	flight time last 90 days : 177 flight time total : 6019 flight time type : 3595
ASRS Report	195327
Person 2
Affiliation	company : air carrier
Function	flight crew : first officer
Qualification	pilot : commercial pilot : instrument
Events
Anomaly	aircraft equipment problem : critical
Independent Detector	other flight crewa
Resolutory Action	other
Consequence	Other
Supplementary
Primary Problem	Aircraft
Air Traffic Incident	other

Narrative:

Approximately 30 mins after takeoff, at FL210 in cruise, right engine oil pressure was observed fluctuating +/- 5-10 psi. Oil pressure had been normal up to that point, approximately 70 psi. Gradually the oil pressure decreased to 25 psi, which then triggered the engine oil pressure warning light on the cwp. Power was reduced on the right engine and a precautionary shutdown was performed according to emergency checklist. ATC was informed of the shutdown and we requested a lower altitude and vectors direct to kcle. After requests were granted passenger were informed of the shutdown as well as air carrier flight control via commercial radio. Single engine procedures were followed for the approach and landing, which went without further incident. After maintenance inspection, oil was discovered leaking from front of chip detector unit. Prior to this flight, at the maintenance hangar, oil was seen coming out 1 of the 'pan drains', but we were told the engine had been washed down and it was nothing more than the runoff of solvent, etc from this wash. Engine had just been through a ground run and mechanics told us there were no leaks.

Original NASA ASRS Text

Title: COMMUTER ACFT HAS OIL PRESSURE FLUCTUATION, THEN WARNING LIGHT. ENG SHUTDOWN. RETURN LAND.

Narrative: APPROX 30 MINS AFTER TKOF, AT FL210 IN CRUISE, R ENG OIL PRESSURE WAS OBSERVED FLUCTUATING +/- 5-10 PSI. OIL PRESSURE HAD BEEN NORMAL UP TO THAT POINT, APPROX 70 PSI. GRADUALLY THE OIL PRESSURE DECREASED TO 25 PSI, WHICH THEN TRIGGERED THE ENG OIL PRESSURE WARNING LIGHT ON THE CWP. PWR WAS REDUCED ON THE R ENG AND A PRECAUTIONARY SHUTDOWN WAS PERFORMED ACCORDING TO EMER CHKLIST. ATC WAS INFORMED OF THE SHUTDOWN AND WE REQUESTED A LOWER ALT AND VECTORS DIRECT TO KCLE. AFTER REQUESTS WERE GRANTED PAX WERE INFORMED OF THE SHUTDOWN AS WELL AS ACR FLT CTL VIA COMMERCIAL RADIO. SINGLE ENG PROCS WERE FOLLOWED FOR THE APCH AND LNDG, WHICH WENT WITHOUT FURTHER INCIDENT. AFTER MAINT INSPECTION, OIL WAS DISCOVERED LEAKING FROM FRONT OF CHIP DETECTOR UNIT. PRIOR TO THIS FLT, AT THE MAINT HANGAR, OIL WAS SEEN COMING OUT 1 OF THE 'PAN DRAINS', BUT WE WERE TOLD THE ENG HAD BEEN WASHED DOWN AND IT WAS NOTHING MORE THAN THE RUNOFF OF SOLVENT, ETC FROM THIS WASH. ENG HAD JUST BEEN THROUGH A GND RUN AND MECHS TOLD US THERE WERE NO LEAKS.

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.