What equipment is on the Standby hydraulic system?

• A. Rudders, LEDs, Standby Yaw Damper, Number 1 and 2 Thrust Reverser
• B. Rudders, Standby Yaw Damper, LEDs
• C. Rudders, LEDs, Standby Yaw Damper, Number 2 Thrust Reverser
• D. Rudders and Landing Gear only

Answer: (A)

The Standby hydraulic system is the emergency source of hydraulic power for the most critical flight-control and indication functions. It must keep the rudder operational to maintain directional control, and it provides the standby yaw damper to help stabilize the aircraft if the primary systems lose power. Visual indicators (LEDs) tied to the standby system alert the crew to its status, which is essential when you’re dealing with a loss of normal hydraulics. In addition, powering both thrust reversers ensures you can decelerate effectively even if the main hydraulic systems aren’t available. Other systems and surfaces that aren’t essential in an emergency aren’t served by this standby system, which is why the combination of rudder, standby yaw damper, the status LEDs, and the thrust reversers covers the equipment most critical to continued safe control and performance.