If the primary hydraulic system fails, what happens to flap usage?

The correct choice indicates that, in the event of a primary hydraulic system failure, the flaps can still be operated using the emergency system. The T-6 aircraft is designed with an emergency hydraulic system specifically to maintain critical aircraft functions, including flap operation, if the primary system experiences a failure. This redundancy is vital for ensuring safe flight operations, allowing pilots to extend or retract the flaps as needed even when the primary hydraulic system is compromised.

The emergency hydraulic system is a backup that engages automatically or can be activated by the pilot, providing an alternative means to control essential aerodynamics, which is crucial for landing and low-speed maneuvers.