Final answer:
Green, red, and black circuit breakers on the flight deck have different significances based on the type of electrical system they control.
Step-by-step explanation:
On a flight deck, the significance of green, red, and black circuit breakers is to indicate the type of electrical system they are associated with. Green circuit breakers typically control circuits that power essential flight systems, such as navigation and communication. Red circuit breakers are used for non-essential flight systems, such as lighting and entertainment. Black circuit breakers are for ground servicing and maintenance purposes.