During which conditions are ground spoilers armed?

Ground spoilers are armed under specific conditions to ensure the safety and effectiveness of the aircraft during landing. The correct circumstance involves having both throttles at idle while meeting certain criteria, typically upon landing. This configuration ensures that the ground spoilers deploy properly to aid in deceleration and to increase the weight on the wheels, improving braking effectiveness when the aircraft is on the runway.

The inclusion of "conditions are met" refers to several factors, such as the aircraft being on the ground and sensing that the wheels have made contact with the runway. These conditions ensure that the spoilers only deploy when they are supposed to, minimizing the risk of accidental activation during flight.

The other scenarios do not meet the requirements for arming the ground spoilers. For example, being airborne suggests that the aircraft is still in flight, during which time the spoilers serve a different function. Advancing the throttles is associated with initiating or maintaining flight, which would not be conducive to deploying ground spoilers. Additionally, having flaps fully retracted does not pertain to the arming of ground spoilers, as these devices are primarily concerned with managing the aircraft's performance on the ground rather than its flight configuration.