A single operative inverter can power all the AC buses, except for the monitor bus. Only the AC generator can power the monitor bus. The AC generator will only power the AC buses if both inverters are off-line. The AC generator automatically drops off-line when the engine-out logic is tripped, as determined by N1 and ECL position. NR is not used in the logic to determine engine-out status. In an emergency if you droop NR below 92% with both engines operative the AC generator should still drop off line.
Last edited by gulliBell; 12th Feb 2016 at 19:53.