Date: 201511
Local time of day: 0601-1200
Location: ZZZ.Airport, US
Weather elements / visibility: Rain
Light: Dawn
Aircraft: Regional Jet 200 ER/LR (CRJ200)
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Climb
Airspace: Class C ZZZ
ATC / advisory: TRACON ZZZ
Reporter organization: Air Carrier
Reporter function: Pilot Flying; First Officer
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Flight Crew Landed As Precaution; Flight Crew Returned To Departure Airport; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Flying with a deferred generator on the right engine. Upon initial climb-out; below 18000 MSL the Captain noticed fluctuating oil pressure in the right engine. We discussed the possibility and probability of returning to [departure airport]. I was pilot flying and took over the radios while the Captain looked for a fluctuating oil pressure checklist in the QRH. The oil pressure was over 25 PSI and had fluctuations between 32-64 PSI. The Captain notified Maintenance of the issue through ACARS. Upon finding the procedure in the QRH we ran the appropriate checklist for fluctuating oil pressure for the right engine. Upon decreasing power to idle the pressure stabilized. We requested vectors to return to [departure airport] and [advised ATC] at this time with an engine oil pressure problem. The procedure stated we could use throttle as necessary so I bumped the power up to around 50% N1. We continued vectors and notified the Dispatcher that we had [advised ATC] and were returning to [departure airport] at this time. The Captain notified the Flight Attendants and the Passengers of the issue as well. At 50% N1 the right engine began to deteriorate and the R ENGINE OIL PRESSURE- MASTER WARNING illuminated. We ran the QRH procedure for ENGINE OIL PRESSURE and again returned the right engine to an idle state. The Master Warning message was no longer illuminated with the engine at idle so we elected to not secure the engine at this time. I prepared the aircraft for an approach to 11 and briefed the approach procedure accordingly. We decided to prepare for the approach in a single engine configuration with flaps 20 due to the possibility of having the right engine fail and not being set up to execute a single engine missed approach procedure properly. Tower advised us of moderate to heavy intensity rain on final with 600 OVC skies and 1 1/2 mile visibility. We shot the ILS to 11 in a single engine; flaps 20; configuration with the right engine at idle and landed without incident.The loss of oil pressure led to an undesirable state in flight and rendered us unable to continue to our planned destination.Maintenance informed us that this aircraft had just been serviced and that the particular engine in question was just returned to proper levels before its flight the night before. The generator failure and subsequent deferral could have been an indication that something was wrong with the oil system in that engine but as these deferrals are common we did not question it much. However; on the preflight inspection I had noticed the oil replenishing reservoir was only at half quantity; the system was turned on; and the door unlatched. I brought this to the attention of the Captain and explained my findings. We contacted Maintenance before boarding and asked if we needed to turn this system off or if there was a minimum level that needed to be in the reservoir. Maintenance indicated to us that as long as there was something in the reservoir that is was not an issue as its only job was to replenish the engines should one run out. After returning to [departure airport]; local Maintenance stated that there was no oil in the engine. The paper work from Maintenance indicated that this particular engine had an oil service the night before but had no quantity listed. Local Maintenance said they added over 6 quarts to this engine to bring it back up to level after we landed. They later told us that there was a problem with the seal to the accessory gearbox and that they had ran the engine for 40 mins and it consumed 5 quarts of oil within that time frame. Proper paperwork and checking of consumption quantities could possibly prevent this in the future. Granted this sounds like a catastrophic failure of a seal; having oil quantities filled out could provide a better paper trail should a similar problem arise in the future.




Synopsis: CRJ-200 First Officer reported oil pressure issues with the right engine and returned to departure airport.