A SF340B's left engine oil pressure was fluctuating above 30 psi; but QRH advised a probable indicat...

Narrative:

We were leveled off at 12;000 ft. I noticed the left engine oil pressure fluctuating. Flight crew took out the appropriate QRH checklist and it said to monitor all engine parameters and to suspect a faulty gauge. Upon further monitoring the engine oil pressure cwp light illuminated intermittently repeatedly. We declared an emergency at this point and asked for the nearest airport. As the pressure dropped below 30 psi we were directed by the QRH to proceed to the engine shutdown checklist. The flight attendant notified the flight deck of oil all over the left engine. We got radar vectors from the TRACON to the ILS. We landed and taxied to the gate under our own power. The plane had a starter generator change and it is possible that the seal in the engine was compromised potentially causing oil to leak. For the kind of maintenance procedure; perhaps a longer runup would be in order before signing it off to ensure integrity of the seals.

Original NASA ASRS Text

Title: A SF340B's left engine oil pressure was fluctuating above 30 PSI; but QRH advised a probable indication problem. Later after the Flight Attendant reported streaming oil; the PSI dropped so an emergency was declared and the flight diverted to a nearby airport where a flat tire also was discovered.

Narrative: We were leveled off at 12;000 FT. I noticed the left engine oil pressure fluctuating. Flight crew took out the appropriate QRH checklist and it said to monitor all engine parameters and to suspect a faulty gauge. Upon further monitoring the engine oil pressure CWP light illuminated intermittently repeatedly. We declared an emergency at this point and asked for the nearest airport. As the pressure dropped below 30 PSI we were directed by the QRH to proceed to the engine shutdown checklist. The Flight Attendant notified the flight deck of oil all over the left engine. We got radar vectors from the TRACON to the ILS. We landed and taxied to the gate under our own power. The plane had a starter generator change and it is possible that the seal in the engine was compromised potentially causing oil to leak. For the kind of maintenance procedure; perhaps a longer runup would be in order before signing it off to ensure integrity of the seals.

Data retrieved from NASA's ASRS site as of July 2013 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.

Attributes
ACN	1015326
Time
Date	201206
Local Time Of Day	0601-1200
Place
Locale Reference	ZZZ.Airport
State Reference	US
Environment
Flight Conditions	VMC
Light	Daylight
Aircraft 1
Make Model Name	SF 340B
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Engine Oil Seals
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Person 2
Function	First Officer Pilot Not Flying
Events
Anomaly	Aircraft Equipment Problem Critical

A SF340B's left engine oil pressure was fluctuating above 30 psi; but QRH advised a probable indication problem. Later after the flight attendant reported streaming oil; the psi dropped so an emergency was declared and the flight diverted to a nearby airport where a flat tire also was discovered.