What is the operable mode of the pack in Normal?

In the Normal operable mode of the Falcon 7X's environmental control system, the main pack is indeed utilized to manage the cabin temperature effectively. In this mode, both the primary and secondary heat exchangers are active, allowing for optimal heating or cooling of the cabin air. This configuration ensures that the cabin maintains a comfortable environment regardless of external conditions.

The main pack's operation is designed to be efficient and provide the necessary climate control while allowing the aircraft to perform effectively in varied operational environments. By utilizing both heat exchangers, the system maximizes performance and reliability. This makes option B the correct answer, as it accurately reflects how the environmental control system operates in Normal mode.

In contrast, the other options suggest either a limited operation of the main pack or inactive systems, which would not provide the necessary climate control expected in a high-performance business jet like the Falcon 7X. Hence, understanding the functioning of the main pack is crucial for optimal aircraft performance and passenger comfort.