The pilot in the rear cockpit has control of which environmental system component?

The rear cockpit pilot specifically has control over the blower fan speed only for the environmental system component associated with their cockpit. This control allows the rear cockpit pilot to adjust the airflow and ventilation within their area, providing them with the ability to manage comfort based on the current conditions and personal preferences.

In terms of cockpit environment management, this limitation on control helps streamline the operation of both cockpits, where the front cockpit pilot has a more comprehensive understanding and control over other systems, such as temperature settings and bleed air inflow. This centralized control helps ensure that one pilot can maintain the necessary environmental conditions without conflicting adjustments from the rear cockpit. Therefore, while the rear cockpit pilot can influence their environment via the blower fan speed, other critical components remain under the primary pilot's control.