B737 flight crew declared an emergency and diverted to nearest suitable after they noticed loss of o...

Narrative:

We had a normal departure. After crossing into [oceanic] airspace we noticed the #1 engine was reading 40% which got our attention. As we continued to watch the oil qty decrease we determined our best course of action was to divert to the closest station. Congestion on the frequency necessitated our use of the call pan-pan to break in. We declared an emergency and requested clearance which was immediately received. We were a little more than an hour out. We got an HF phone patch to dispatch / [maintenance control] and notified them of our intentions. The oil qty indication continued to decrease and before the descent indicated as low as 21%. Once the nose was pointed down there was a slight increase in the indication. Our arrival was normal / uneventful. At the gate with the engine shut down for a period of time the oil quantity read 40%. Contract maintenance arrived and conferred with [maintenance control]. The residual oil was cleaned from the engine and cowl and the engine refilled with oil. We ( the crew ) preformed an idle engine run at the gate while maintenance observed the engine. It was determined that the oil was coming from the idg drain pad tube but not the location of the actual leak. The rate was measured and [maintenance control] determined that it was within acceptable (at idle) parameters. They said we were good to go. My personal decision was that to me that it was not acceptable and I would not take the aircraft in that condition. A leak at idle is one thing it's an entirely different matter at high power and without a real fix I would not take that aircraft over the water (class 2 ) at night to an intended destination with poor weather. The oil quantities were looked at on the ground but it was the situation where I can't recall the actual numbers but know they were acceptable. The oil had been topped off prior to arriving but I have no idea when the leak developed and had nothing to gauge the loss against. [Flight was cancelled]. We had the passengers on the aircraft the whole time prior to the cancellation due to the customs issue and the hope that the leak might be a quick fix.

Original NASA ASRS Text

Title: B737 flight crew declared an emergency and diverted to nearest suitable after they noticed loss of oil quantity in the right engine. After landing the crew refused to fly the aircraft on to the final destination when Maintenance determined the problem could be deferred.

Narrative: We had a normal departure. After crossing into [oceanic] airspace we noticed the #1 engine was reading 40% which got our attention. As we continued to watch the oil qty decrease we determined our best course of action was to divert to the closest station. Congestion on the frequency necessitated our use of the call pan-pan to break in. We declared an emergency and requested clearance which was immediately received. We were a little more than an hour out. We got an HF phone patch to dispatch / [Maintenance Control] and notified them of our intentions. The oil qty indication continued to decrease and before the descent indicated as low as 21%. Once the nose was pointed down there was a slight increase in the indication. Our arrival was normal / uneventful. At the gate with the engine shut down for a period of time the oil quantity read 40%. Contract Maintenance arrived and conferred with [Maintenance Control]. The residual oil was cleaned from the engine and cowl and the engine refilled with oil. We ( the crew ) preformed an idle engine run at the gate while maintenance observed the engine. It was determined that the oil was coming from the IDG drain pad tube but not the location of the actual leak. The rate was measured and [Maintenance Control] determined that it was within acceptable (at idle) parameters. They said we were good to go. My personal decision was that to me that it was not acceptable and I would not take the aircraft in that condition. A leak at idle is one thing it's an entirely different matter at high power and without a real fix I would not take that aircraft over the water (class 2 ) at night to an intended destination with poor weather. The oil quantities were looked at on the ground but it was the situation where I can't recall the actual numbers but know they were acceptable. The oil had been topped off prior to arriving but I have no idea when the leak developed and had nothing to gauge the loss against. [Flight was cancelled]. We had the passengers on the aircraft the whole time prior to the cancellation due to the customs issue and the hope that the leak might be a quick fix.

Data retrieved from NASA's ASRS site 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.

Attributes
ACN	1240430
Time
Date	201502
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZZ.Airport
State Reference	FO
Environment
Light	Daylight
Aircraft 1
Make Model Name	B737 Undifferentiated or Other Model
Operating Under FAR Part	Part 121
Flight Phase	Cruise
Route In Use	Oceanic
Flight Plan	IFR
Component
Aircraft Component	Turbine Engine
Person 1
Function	Pilot Flying Captain
Qualification	Flight Crew Air Transport Pilot (ATP)
Experience	Flight Crew Last 90 Days 163 Flight Crew Total 5797 Flight Crew Type 5797
Person 2
Function	Pilot Not Flying First Officer
Experience	Flight Crew Last 90 Days 240 Flight Crew Type 713
Events
Anomaly	Aircraft Equipment Problem Less Severe

B737 flight crew declared an emergency and diverted to nearest suitable after they noticed loss of oil quantity in the right engine. After landing the crew refused to fly the aircraft on to the final destination when maintenance determined the problem could be deferred.