Final answer:
The fuel state that illuminates the FUEL LO light, MASTER CAUTION light, and activates the fuel low voice alert is when the fuel level drops below a certain threshold.
Step-by-step explanation:
The fuel state that illuminates the FUEL LO light, MASTER CAUTION light, and activates the fuel low voice alert is when the fuel level drops below a certain threshold.
These indicators are used in aircraft systems to warn the pilots about the low fuel level.
When the fuel level reaches a critical point, the FUEL LO light and the MASTER CAUTION light will both illuminate, and a voice alert will be triggered to notify the pilots of the low fuel.