Date: 201302
Location: ZZZZ.ARTCC, FO
Flight conditions: VMC
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
ATC / advisory: Center ZZZZ
Aircraft component: Powerplant Lubrication System
Component problem: Failed
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Second reporter function: Pilot Flying; Captain
Anomaly: Aircraft Equipment Problem Critical
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Inflight Shutdown; Flight Crew Landed in Emergency Condition; Flight Crew Returned To Departure Airport; General Declared Emergency; General Maintenance Action
Contributing factors: Aircraft; Human Factors
Primary problem: Aircraft

Narrative: We were at FL370 in cruise. The first indication noticed by the crew was the low oil pressure alert for the #2 Engine. The oil pressure was rolling back through the yellow and below 13 PSI as I was pulling the QRH. We followed the QRH procedure for Low Oil Pressure to Engine Shutdown. We declared an emergency with ATC and requested FL200 after consulting FMC engine out altitude of FL226. We received clearance for direct [the departure airport] and to descend to FL200. After the turn was executed; the Captain transferred controls to me and alerted Dispatch (via ACARS) and briefed flight attendants and passengers. The Captain returned and received clearance to the IAF for the ILS. We briefed approach and arrival; analyzed the non-normal configuration landing chart; single-engine go-around procedures; confirmed ARFF would be available and standing by; completed QRH through approach and landing and executed a single engine overweight landing.


Second narrative: My First Officer advised me that we had a Master Caution and the Engine Display was annunciating LOW OIL PRESS on the Number 2 Engine. We checked the oil pressure indication and observed it rapidly falling and as we were watching; it fell below red line and appeared to stop at about 10 PSI. I retained control of the aircraft and asked my First Officer to run the checklist. I disconnected the autopilot and hand flew the aircraft while my First Officer accomplished the shutdown. Once the power was pulled back and the aircraft stabilized; I asked my First Officer to declare an emergency with ATC and request descent to FL200 as our single engine max altitude was being displayed as approximately FL220. Center cleared us direct to the airport and approved our descent to FL200. I set MCT on the Number 1 Engine; slowed the aircraft to our single engine speed of 243 KTS; engaged the autopilot; and began a driftdown while my First Officer completed the remainder of the 'Engine Failure/Shutdown' checklist. Once he reported the checklist complete; I transferred control of the aircraft to him so I could do some communicating and brief for the arrival. I first contacted my Purser and advised her that we had shutdown an engine due to low oil pressure and that we were returning. I gave her an estimate of 20 minutes until landing and that an evacuation was not anticipated and that she did not need to prepare the cabin for one. I then made a PA to our passengers explaining that we had a low oil pressure indication on an engine and that; as a precaution; we had shut the engine down and would be returning. I emphasized we were in no danger; that we receive a lot of training dealing with just this type of situation; that we would be landing soon; that our in flight crew would be preparing the cabin for landing and that I appreciated their understanding and cooperation. I then sent an ACARS message to our Dispatcher that we had shutdown an engine due to low oil pressure; and were returning. I began running the 'Single Engine Approach and Landing' checklist and briefed the arrival. There seemed to be some confusion with ATC as the Approach Controller asked us if we needed any emergency service. I emphasized to him at that point that we had shut an engine down; we had declared an emergency; and that; yes we were requesting emergency equipment upon landing. That seemed to get the point across. The rest of the approach and landing was uneventful. Even at high density altitude and landing weight about 6;000 LBS over maximum landing weight we only used about 2/3 of the runway and were able to exit and taxi to the gate without any assistance. Once we arrived at the gate; I made a logbook entry stating we had shutdown Number 2 Engine due to low oil pressure; and that we had completed an overweight single engine landing. I was subsequently contacted by Maintenance Control and spoke to an Engine Specialist who requested more specific information regarding what kind of oil pressure indications we had received and how much time the engine was run at low oil pressure before being shutdown. Interestingly; it wasn't until we were at the gate and talking to a Maintenance Technician that we noticed the oil quantity at zero. We had been so focused on the oil pressure that we failed to even see that the oil quantity was zero. Maintenance Control advised us that the ACARS download showed that the loss of oil and low oil pressure happened very quickly and that there was really nothing we could have done to save the engine. Both my First Officer and I commented to each other that we remembered the oil tank was full on that engine before departure because it stuck out to us that it was reading 100% when we initialized the ACARS for the flight.


Synopsis: B737 flight crew experiences loss of engine oil and engine oil pressure shortly after level off at FL370. The engine is shutdown and flight returns to the departure airport for an overweight landing.