FAA Maintenance Alert

Gulfstream: G550; Arcing Emergency Inverter; ATA 2422
“When turning the main battery switches on,” writes the submitter, “the mechanic heard a loud popping sound, followed by the aroma of smoke in the entrance area of the aircraft. The floorboard was removed and (we) found water from the forward lavatory area had been running onto the top of the emergency inverter (P/N 1-002-0102-1346), causing water and AC voltage to meet (the water won). The lavatory areas on both of our G550’s were inspected for leaks...(none were found, but...) areas were found where water had been sitting. It is possible that, when stowing the sink (it’s hinged—folds up into a close-out) residual water is dumping into the close-out. The emergency inverter was replaced, and we shut the water supply off to the forward lavatory sinks (on both aircraft).” MORE