During a primary hydraulic system failure, which device can be extended using the emergency package?

The ability to extend both the landing gear and the flaps during a primary hydraulic system failure is vital for ensuring safety in emergency situations. The emergency package, often found in aircraft, is designed specifically to provide alternative means of operation when the primary hydraulic system is compromised.

For landing gear, the emergency extension mechanism typically involves using gravity or a manual system that allows the gear to lower safely, even if the primary hydraulic system is not functional. Similarly, flaps may also have a backup system, either hydraulic or mechanical, enabling them to be extended to a degree that assists in approach and landing, improving the aircraft's aerodynamic characteristics during an emergency descent.

Having both systems available for emergency use is critical in maintaining control and maneuverability of the aircraft during a failure scenario. Thus, the option indicating that both landing gear and flaps can be extended is the correct choice.