Final answer:
If only one generator is operating, both the galley and cabin electrical buses should continue to receive power, although with possible limitations to non-essential systems. Aircraft like the 767 have electrical systems with redundancy to cope with generator failures. Loss of power in flight would necessitate rerouting power to prioritize critical systems.
Step-by-step explanation:
When only one generator is operating in flight on an aircraft similar to the 767, power will generally be supplied to both the galley and the cabin electrical buses, although at a possibly reduced capacity. Modern aircraft have sophisticated electrical systems designed to ensure redundancy. The failure of one generator should activate the plane's electrical system to reroute power, allowing continued operation of essential and non-essential systems.
However, the availability of power to non-essential systems like the galley could be limited in order to prioritize more critical systems. An example of this is the famous 'Gimli Glider' incident, where an aircraft lost power to all engines. In that emergency situation, the pilots successfully glided the plane to a landing without powered systems.
While electric airplanes are a subject of research, as noted in Box 17.1, the technology is not yet able to sustain typical airliner operations. Battery storage has potential but is currently insufficient to replace traditional power sources in most commercial flight applications.