Definition
The generator or generators on a multi-engine aircraft that remain functional and continue to produce electrical power after one or more other generators have failed. These are the units the pilot must rely on to supply the aircraft's electrical system for the remainder of the flight.
Plain English
The generators that are still working after another one has failed. They are the ones now doing all the electrical work for the aircraft.
Context Anchor
Seen in generator failure discussions and checklists, especially when deciding what electrical power remains after one generator has failed.
Derivation
Generator comes from a Latin word meaning “to produce” or “to bring forth.” In aviation, a generator produces electrical power for the aircraft. Operating means working or functioning, so operating generator(s) are the generators that are actually producing power.
Why Pilots Care
Loss of one or more operating generators removes primary electrical power, forcing immediate use of backup systems and checklists to prevent loss of instruments and avionics.
Grounding Statement
If a generator is operating, it is making electricity for the aircraft; if it is not, the aircraft must get power from another source or reduce electrical use.
Intuition Check
Do not assume operating means merely installed or switched on. Here it means the generator is actually functioning and producing usable electrical power.
Example Sentence 1
After the left generator failed, the crew reduced electrical load to keep the operating generator within its rated output.
Example Sentence 2
When one operating generator failed, the pilot cross-checked voltage and load to confirm the remaining unit was still supplying the bus.