GVII - Servicing oil using the ground service bus

If you look at the Frequently Asked Questions section of the Gulfstream GVII manuals you will see this one: "Can I remotely replenish my oils and hydraulics on the G500?" The answer is yes, "if you select the main batteries ON and the Ground Service Bus switch ON." In previous Gulfstreams all you needed was the ground service bus, for this one you need both. Why? We asked the guy in charge of the system at Gulfstream and here is what he said:

"At one-time Rsvr Qty Left and Right were wired to RDC 20. Program said we needed redundancy so we split off and wired to RDC22 for the Right System. Unknowing at the time, RDC22 is not wired for GSB. As such, not available for replenishment via the Replenisher System on the ground with aircraft powered down. At the time we realized, the design was mature and to reconcile would take wiring changes as well as re-allocation of RDC's. Program at that time opted not to pursue the change. Since then, it has come up again and PR015301 was initiated on 10.04.18. It is still shown as in "Root Cause" and classified as a 3A (Significant Negative Impact). Since is still as "Root Cause", I do not know what the impacts are for the change nor the time frame to implement."

We hear there is a program change request to fix this, but for now you need the battery switch on as well as the ground service bus.