Narrative:

Right engine shut down by crew following 'low oil press right' EICAS message. Enroute [on long overwater leg] satcom voice deferred. Enroute the first officer noticed the #2 engine oil quantity indicating 1 quart. All other engine indications were normal. The first officer stated that during his transition training (this was the first officer's first flight after training) they had been told that there was no lower limit to oil quantity. He then checked the flight manual and we both noted statement stating such. We also checked the flight manual for any checklists concerning low oil quantity and the limits section for further guidance. After noting there were no checklist concerning low oil quantity and no lower limit for oil quantity while enroute we verified that the oil pressure and oil temp were well within normal operating parameters. We then sent maintenance and dispatch a message via ACARS stating the oil quantity was indicating 1 quart and all other engine indications were normal. We sent a second message to maintenance inquiring about maintenance history; servicing; and oil consumption. A few minutes later maintenance replied; 'oil quantity is the least reliable of oil parameters. Check engine for oil use. Well within operating limits. Monitor oil press and oil temp. Keep us posted.' we then received a second message from maintenance stating; 'have reviewed maintenance history; computer tracked oil usage. Both appear normal. Please monitor oil press and temp. Max continuous temp is 166c; min oil press 70 psi. If you get close to either; let us know and follow your flight manual'. The first officer and I discussed if we should turn around and go back. Both of us felt that with the info from maintenance it was an indication problem not a loss of oil. I was also under the impression that maintenance would monitor our engine parameter and trends enroute via datalink and felt like they would have a clearer picture of what was happening with the engine. Enroute the oil quantity indication went to 0. We noted oil pressure and temp were normal and consistent with the left engine. We did notice that the right engine oil pressure was fluctuating a bit when compared to the left engine. We sent maintenance and dispatch these indications; including the fluctuating oil pressure on the right engine. We also included a question to maintenance regarding when the EICAS message would come on for low oil quantity and if it was a direct read from the gauge. As time passed the first officer and I noticed the oil pressure now was less than previously noted; still well in the normal operating range; oil temp was good; and engine vibration was consistent with the other engine. With the oil pressure decreasing we began to think this may be more than an indication problem; but didn't have enough info to make a complete decision. We sent maintenance all indications noted; including oil pressure fluctuations and oil pressure decreasing slowly. We still had a good functioning engine; but felt like we needed to have dispatch get operations involved and sent a message to dispatch requesting such. As we continued to the pet we received the following message from maintenance; 'EICAS message at 70 psi. Op transmitter is direct read to cockpit. There may be an input-output module effecting the oil qty. That is the only cmc message we currently see. Please enter log items for problems reported. Thanks for the help.' still not sure of exactly what problem we had going on; my first officer and I decided to come up with a plan of action if the engine quit or we had to shut it down. We still were under the impression it was probably an indication problem because of previous messages from maintenance and we hadn't received any info from maintenance to the contrary; the engine still had good oil pressure (even though it was still decreasing slowly); oil temp was normal; and there was no little or no vibration indicated. We felt like it was a good time to review all procedures pertinent to the situation; i.e. Lo engine oil press checklist in the flight manual; drift down; emergency section of the chapter; etc. We reviewed the eng out page on the FMC CDU. We determined that if we needed to drift down we would need to initially turn left off the track because of the other aircraft on our track that were to our right at lower altitudes. We looked at what altitude to descend to and at what airspeed. We also reviewed emergency communications. As we approached the etp we received this message from maintenance; 'originally you reported a problem with oil quantity indication. That is deferrable. Everything I have been able to look at suggests that is the problem. Now you are talking about oil press fluctuating. Is that correct?' my first officer and I were a bit surprised by this question. First; we had always stated that the oil quantity indications were 1 quart or 0. We had never stated it was a problem with oil quantity indication. Second; we had sent at least a couple messages that the oil pressure was fluctuating. The only message to maintenance that didn't contain that indication was the first message. At this point in time I believe we had passed the etp. The right and left engines were performing normally; but we new there could very well be a problem. The oil press on #2 was still going down slowly (still within limits); the oil temp was good; and engine vibration was consistent with the other engine. My first officer and I discussed the situation and decided to look at airports and weather. I stated that I felt like it would be better to divert to an airport with a long runway because we would be at flaps 20 for single engine. We sent several messages to dispatch describing our intentions if we had to shut down the engine and requested info for [area airports]. After much discussion we decided that ZZZ would be the best divert airport because both of us had been into ZZZ within the last week. At that time I asked the purser to come to the cockpit and briefed her. She was briefed about the situation; what it could become; and what our response would be. We advised her that we still were running on two engines but might have to shut the right engine down. We would descend down to a lower altitude and divert to ZZZ. About this same time we received this message from maintenance; 'if pressure was steady and now with oil quantity zero; the pressure is starting to fluctuate; then there may be a problem with oil quantity; not an indication problem. Follow your flight manual.' I wished we had received this message a lot earlier; but now we new the problem and started to implement plans. The first officer and I again went over our plan of action. We decided to wait until the EICAS message 'engine lo oil press right' came on and then we would commence with shutting down the engine and starting the drift down procedure. I called the purser and told her at some point we would probably shut the engine down and divert to ZZZ. I gave her an estimated time to ZZZ. I also said I would make an announcement; prior to shutting the engine down; to the passengers about what was going on were we would divert to and reassure them everything would be fine. [Later] the oil pressure on the right engine decreased to 70 psi then back to 74 psi. The EICAS message momentarily came on and went away. We decided to wait until we had a steady EICAS message before we would start the checklist. I made an announcement to the passenger as planned and briefed. Just a few minutes later we had a steady EICAS message; 'engine lo oil press'. We proceeded with the checklist and shut the right engine down. We followed the drift down procedure; declared an emergency via cpdlc and over HF. We voiced 'mayday; mayday' over 123.45. We then turned on all exterior lights and exited the track to the left at the single engine drift down airspeed that was depicted on the CDU. Once we were 15 miles left of course we parallel the track using LNAV and continued the descent. We descended to our single engine operating altitude and asked ATC (via cpdlc) for direct ZZZ. Clearance was received and we were given a block altitude of FL200 to FL240. During this time a company first officer that was riding in the back had the purser call us up to ask if he could be any help. We had him come into the cockpit and assume a helpful role (this first officer had come in prior to the flight and introduced himself and gave us his seat assignment). His help was appreciated. We briefed the approach; the single engine missed approach profile and the missed approach procedure. The approach was uneventful as well as the landing. We taxied off the runway and proceeded to the gate. I debriefed the flight attendant's after the flight to get their comments and thoughts. Communication was the biggest problem and hindrance during the event. Satcom voice was deferred inop. Prior to the flight ACARS did not work either and maintenance was about to try and defer that as well. They finally got the ACARS to work before the flight departed. I'm not sure if I would take an aircraft over the ocean without either after this experience. As far as I'm concerned we did a good job with the information we had. The crew worked well with each other. My first officer brought the one mistake we made and were able to identify to my attention the day after the event. As we were boarding the crew van to go back to the airport for the deadhead back; the first officer stated to me he had realized just that morning we had used the checklists out of the flight manual and not the electronic checklist (ecl). He had taken the checklists out of the flight manual binder and clipped it in the chart holder next to the side window. We had used these checklists for review during the event. When it came time to actually shut down the engine he read from those and not the ecl. I guess I was so caught up in shutting down an engine over the ocean and making sure I verified all the checklist items I didn't even notice. I have no idea of how I missed that and no excuses for it.

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Original NASA ASRS Text

Title: A B777 Captain reported low oil quantity on an overwater flight. The engine was shut down when oil pressure fell below limits; an emergency was declared; and the flight diverted to the nearest suitable airport.

Narrative: Right engine shut down by crew following 'LOW OIL PRESS R' EICAS message. Enroute [on long overwater leg] SATCOM voice deferred. Enroute the First Officer noticed the #2 engine oil quantity indicating 1 quart. All other engine indications were normal. The First Officer stated that during his transition training (this was the First Officer's first flight after training) they had been told that there was no lower limit to oil quantity. He then checked the flight manual and we both noted statement stating such. We also checked the flight manual for any checklists concerning low oil quantity and the limits section for further guidance. After noting there were no checklist concerning low oil quantity and no lower limit for oil quantity while enroute we verified that the oil pressure and oil temp were well within normal operating parameters. We then sent Maintenance and Dispatch a message via ACARS stating the oil quantity was indicating 1 quart and all other engine indications were normal. We sent a second message to Maintenance inquiring about maintenance history; servicing; and oil consumption. A few minutes later Maintenance replied; 'Oil quantity is the least reliable of oil parameters. Check engine for oil use. Well within operating limits. Monitor oil press and oil temp. Keep us posted.' We then received a second message from Maintenance stating; 'have reviewed maintenance history; computer tracked oil usage. Both appear normal. Please monitor oil press and temp. Max continuous temp is 166c; min oil press 70 psi. If you get close to either; let us know and follow your Flight Manual'. The First Officer and I discussed if we should turn around and go back. Both of us felt that with the info from Maintenance it was an indication problem not a loss of oil. I was also under the impression that Maintenance would monitor our engine parameter and trends enroute via DATALINK and felt like they would have a clearer picture of what was happening with the engine. Enroute the oil quantity indication went to 0. We noted oil pressure and temp were normal and consistent with the left engine. We did notice that the right engine oil pressure was fluctuating a bit when compared to the left engine. We sent Maintenance and Dispatch these indications; including the fluctuating oil pressure on the right engine. We also included a question to Maintenance regarding when the EICAS message would come on for low oil quantity and if it was a direct read from the gauge. As time passed the First Officer and I noticed the oil pressure now was less than previously noted; still well in the normal operating range; oil temp was good; and engine vibration was consistent with the other engine. With the oil pressure decreasing we began to think this may be more than an indication problem; but didn't have enough info to make a complete decision. We sent Maintenance all indications noted; including oil pressure fluctuations and oil pressure decreasing slowly. We still had a good functioning engine; but felt like we needed to have dispatch get Operations involved and sent a message to dispatch requesting such. As we continued to the PET we received the following message from Maintenance; 'EICAS message at 70 PSI. Op transmitter is direct read to cockpit. There may be an input-output module effecting the oil qty. That is the only CMC MSG we currently see. Please enter log items for problems reported. Thanks for the help.' Still not sure of exactly what problem we had going on; my First Officer and I decided to come up with a plan of action if the engine quit or we had to shut it down. We still were under the impression it was probably an indication problem because of previous messages from Maintenance and we hadn't received any info from Maintenance to the contrary; the engine still had good oil pressure (even though it was still decreasing slowly); oil temp was normal; and there was no little or no vibration indicated. We felt like it was a good time to review all procedures pertinent to the situation; i.e. LO ENG OIL PRESS checklist in the Flight Manual; Drift down; Emergency section of the Chapter; etc. We reviewed the Eng Out page on the FMC CDU. We determined that if we needed to drift down we would need to initially turn left off the track because of the other aircraft on our track that were to our right at lower altitudes. We looked at what altitude to descend to and at what airspeed. We also reviewed emergency communications. As we approached the ETP we received this message from Maintenance; 'Originally you reported a problem with oil quantity indication. That is deferrable. Everything I have been able to look at suggests that is the problem. Now you are talking about oil press fluctuating. Is that correct?' My First Officer and I were a bit surprised by this question. First; we had always stated that the oil quantity indications were 1 quart or 0. We had never stated it was a problem with oil quantity indication. Second; we had sent at least a couple messages that the oil pressure was fluctuating. The only message to Maintenance that didn't contain that indication was the first message. At this point in time I believe we had passed the ETP. The right and left engines were performing normally; but we new there could very well be a problem. The oil press on #2 was still going down slowly (still within limits); the oil temp was good; and engine vibration was consistent with the other engine. My First Officer and I discussed the situation and decided to look at airports and weather. I stated that I felt like it would be better to divert to an airport with a long runway because we would be at Flaps 20 for single engine. We sent several messages to dispatch describing our intentions if we had to shut down the engine and requested info for [area airports]. After much discussion we decided that ZZZ would be the best divert airport because both of us had been into ZZZ within the last week. At that time I asked the Purser to come to the cockpit and briefed her. She was briefed about the situation; what it could become; and what our response would be. We advised her that we still were running on two engines but might have to shut the right engine down. We would descend down to a lower altitude and divert to ZZZ. About this same time we received this message from Maintenance; 'If pressure was steady and now with oil quantity zero; the pressure is starting to fluctuate; then there may be a problem with oil quantity; not an indication problem. Follow your Flight Manual.' I wished we had received this message a lot earlier; but now we new the problem and started to implement plans. The First Officer and I again went over our plan of action. We decided to wait until the EICAS message 'ENG LO OIL PRESS R' came on and then we would commence with shutting down the engine and starting the drift down procedure. I called the Purser and told her at some point we would probably shut the engine down and divert to ZZZ. I gave her an estimated time to ZZZ. I also said I would make an announcement; prior to shutting the engine down; to the passengers about what was going on were we would divert to and reassure them everything would be fine. [Later] the oil pressure on the right engine decreased to 70 PSI then back to 74 PSI. The EICAS message momentarily came on and went away. We decided to wait until we had a steady EICAS message before we would start the checklist. I made an announcement to the passenger as planned and briefed. Just a few minutes later we had a steady EICAS message; 'ENG LO OIL PRESS'. We proceeded with the checklist and shut the right engine down. We followed the drift down procedure; declared an emergency via CPDLC and over HF. We voiced 'MAYDAY; MAYDAY' over 123.45. We then turned on all exterior lights and exited the track to the left at the single engine drift down airspeed that was depicted on the CDU. Once we were 15 miles left of course we parallel the track using LNAV and continued the descent. We descended to our single engine operating altitude and asked ATC (via CPDLC) for direct ZZZ. Clearance was received and we were given a block altitude of FL200 to FL240. During this time a Company First Officer that was riding in the back had the Purser call us up to ask if he could be any help. We had him come into the cockpit and assume a helpful role (This First Officer had come in prior to the flight and introduced himself and gave us his seat assignment). His help was appreciated. We briefed the approach; the single engine missed approach profile and the missed approach procedure. The approach was uneventful as well as the landing. We taxied off the runway and proceeded to the gate. I debriefed the Flight Attendant's after the flight to get their comments and thoughts. Communication was the biggest problem and hindrance during the event. SATCOM voice was deferred inop. Prior to the flight ACARS did not work either and Maintenance was about to try and defer that as well. They finally got the ACARS to work before the flight departed. I'm not sure if I would take an aircraft over the ocean without either after this experience. As far as I'm concerned we did a good job with the information we had. The crew worked well with each other. My First Officer brought the one mistake we made and were able to identify to my attention the day after the event. As we were boarding the crew van to go back to the airport for the deadhead back; the First Officer stated to me he had realized just that morning we had used the checklists out of the Flight Manual and not the Electronic Checklist (ECL). He had taken the checklists out of the Flight Manual binder and clipped it in the chart holder next to the side window. We had used these checklists for review during the event. When it came time to actually shut down the engine he read from those and not the ECL. I guess I was so caught up in shutting down an engine over the ocean and making sure I verified all the checklist items I didn't even notice. I have no idea of how I missed that and no excuses for it.

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.