Narrative:

During initial climb out it was noticed by the captain (pilot not flying) that the left oil pressure gauge (#1 engine) was oscillating rapidly between approximately 30 psi and 55 psi. This was not accompanied by any engine surging or abnormal indications such as N1; oil temperature; N2; etc. The captain completed the engine oil pressure fluctuation abnormal checklist in the QRH which had the flight crew level/reduce altitude and reduce power to try to stabilize the engine oil pressure. This level off (initially at 12;000 ft) was coordinated with air traffic control. It was found that if power was reduced to approximately 65-70% N1 that the oil pressure reading would stabilize at a normal value. The crew's interpretation of the fluctuating oil pressure QRH checklist was that stabilizing the pressure reading was the goal of the checklist and once stabilized to not increase altitude or power setting unless necessary for safety of flight. The dispatcher was contacted via radio and a subsequent call to maintenance control was made. The maintenance controller advised that the flight should continue and contact them on the ground. After discussion amongst the flight crewmembers (captain and first officer); the stance of the flight crew was that maintaining oil pressure stability was the prime motivation of the oil pressure fluctuation QRH checklist and that flying to [destination] at a reduced power state or low altitude would be outside of normal operational procedures and unwise. Furthermore; once the aircraft arrived on the ground this may result in extensive maintenance delays. This opinion of the flight crew was supported by previous maintenance log entries for much the same issue and was most likely not an event that could be signed off with an 'ops check good.' maintenance control and the dispatcher were consulted and this belief that it would be safer to return to [departure airport] was shared. The group came to a consensus that the flight would return. The flight attendant was kept advised of the situation through multiple interphone communications and the passengers were made aware of the necessity for the air return via PA announcement. The flight returned without further incident using reduced power on the left engine to maintain stability of the oil pressure reading. It was subsequently determined by line maintenance that on first inspection there was an oil leak in the engine oil bearing #1.

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Original NASA ASRS Text

Title: An air carrier Captain reported fluctuating oil pressure; and decided to return to departure airport.

Narrative: During initial climb out it was noticed by the Captain (pilot not flying) that the left oil pressure gauge (#1 Engine) was oscillating rapidly between approximately 30 PSI and 55 PSI. This was not accompanied by any engine surging or abnormal indications such as N1; oil temperature; N2; etc. The Captain completed the Engine Oil Pressure Fluctuation abnormal checklist in the QRH which had the flight crew level/reduce altitude and reduce power to try to stabilize the engine oil pressure. This level off (initially at 12;000 FT) was coordinated with Air Traffic Control. It was found that if power was reduced to approximately 65-70% N1 that the oil pressure reading would stabilize at a normal value. The crew's interpretation of the fluctuating oil pressure QRH checklist was that stabilizing the pressure reading was the goal of the checklist and once stabilized to not increase altitude or power setting unless necessary for safety of flight. The Dispatcher was contacted via radio and a subsequent call to Maintenance Control was made. The Maintenance Controller advised that the flight should continue and contact them on the ground. After discussion amongst the flight crewmembers (Captain and First Officer); the stance of the flight crew was that maintaining oil pressure stability was the prime motivation of the Oil Pressure Fluctuation QRH checklist and that flying to [destination] at a reduced power state or low altitude would be outside of normal operational procedures and unwise. Furthermore; once the aircraft arrived on the ground this may result in extensive maintenance delays. This opinion of the flight crew was supported by previous maintenance log entries for much the same issue and was most likely not an event that could be signed off with an 'ops check good.' Maintenance Control and the Dispatcher were consulted and this belief that it would be safer to return to [departure airport] was shared. The group came to a consensus that the flight would return. The Flight Attendant was kept advised of the situation through multiple interphone communications and the passengers were made aware of the necessity for the air return via PA announcement. The flight returned without further incident using reduced power on the left engine to maintain stability of the oil pressure reading. It was subsequently determined by Line Maintenance that on first inspection there was an oil leak in the Engine Oil Bearing #1.

Data retrieved from NASA's ASRS site as of April 2012 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.