Under normal operations, which devices are operated by the primary hydraulic system?

• A. Landing gear/main gear doors, flaps, speed brake, and trim aid device
• B. Landing gear, flaps, speed brake, and flight controls
• C. Landing gear/main gear inboard doors, flaps, speed brake, and nose wheel steering
• D. Landing gear, main gear inboard doors, flaps, speed brake, and wheel brakes

Answer: (C)

The main idea here is that the primary hydraulic system powers the high-load actuators that handle essential flight and ground maneuvering functions. In normal operations, this system provides hydraulic pressure to extend and retract the landing gear and its doors, position the flaps, deploy and retract the speed brake, and operate the nose wheel steering. These components require strong, reliable actuation from hydraulics and are typically fed by the primary system so pilots can control gear, flaps, speed brakes, and steering smoothly from the cockpit. Wheel brakes, while hydraulic, usually come from a separate brake system, not the primary system, which is why they aren’t included.