Flight Crew Last 90 Days 30; Flight Crew Total 10000; Flight Crew Type 3000
Aircraft Equipment Problem Critical
Flight Crew Landed As Precaution; Flight Crew Diverted; General Maintenance Action
Aircraft
We were in cruise at FL350 approaching BAREE; when I noticed that the left engine oil quantity was zero. I then checked all the other engine indications and discovered that the left engine oil pressure; while in limits; was about 100 PSI lower and the oil temp was significantly higher than the right engine. I contacted Maintenance Control and Dispatch on SATCOM. After reviewing all the indications and previous write-ups we concluded that the scavenge pump on the number 1 engine had failed; and that it could cause us to lose the engine enroute. He recommended we not cross the Atlantic like this. Dispatch recommended we divert and we concurred. We dumped fuel down to below maximum landing weight and landed uneventfully. If this situation could have actually led to an in-flight shutdown; or worse; maybe there should be some EICAS indication associated with it. We had no indications other than the fact that I noticed the oil quantity was indicating zero.
During the descent; we observed the number 1 engine oil quantity indication slowly return to normal.
A eastbound transatlantic air carrier flight diverted to a stateside airport after experiencing indications of low oil quantity and pressure and high oil temperature in the left engine.