Before pressurizing the No. 2 and No. 3 hydraulic systems, what should be set on the INBD ELEVATOR panel?

The correct response is “Off” because the INBD ELEVATOR panel must be in the Off position before pressurizing the No. 2 and No. 3 hydraulic systems. This is a critical safety measure that prevents potential hazards associated with hydraulic pressure affecting the control surfaces, especially during system checks or maintenance procedures. When the panel is set to Off, it ensures that the elevators are not inadvertently activated while the hydraulic systems are being pressurized, which could result in unintended movement or malfunction.

This procedure safeguards against mixing hydraulic power with elevator operation, creating a safer environment for maintenance personnel and ensuring the integrity of the control systems during pressurization. Proper adherence to this protocol is essential for maintaining the operational reliability and safety of the aircraft's hydraulic systems.