The worst offender in my books was A342's and A343's. After an eight hour flight, each engine would need on average 3 or 4 quarts of oil. The outboard engines were a pain because they were so high up.
I remember that the oil inlet was only just big enough to take a steady but moderate stream of oil, which we used to pour directly from the can. The spatial relationship between the oil service door and oil tank inlet however, was definitely designed with use of an oil pouring spout in mind.
I eventually worked out a set of angles and timing such that I could simultaneously get the can through the door, twist it upside down, and get it to sit on the scupper by itself whilst the oil poured into the tank. Interestingly, the following business jets have a central replenishment system for the individual engine mounted oil tanks.
I don’t personally know of any commercial types with such an arrangement, though I do vaguely remember a remote oil replenishment system for #2 engine on DC-10’s / MD
-11’s. On the 747, there is a centralised hydraulic fluid replenishment system in the wheel well that goes to all four hydraulic reservoirs located in the aft section of the engine struts, so making a similar system for engine oil is certainly feasible.
I suspect however, that such systems aren’t seen on commercial types, because a direct visual inspection of the oil quantity by a mechanic is the best way to ensure safety, especially for ETOPS flights. In fact, with the last company I worked for, different mechanics would check the LH and RH engine and IDG oils on ETOPS flights for this exact reason.
[Edited 2013-04-24 19:31:29]