Which system helps create airflow for the AC system while on the ground?

The Venturi effect is the correct answer as it describes a phenomenon where airflow is created as a fluid (in this case, air) moves through a constricted section of a duct or pipe, resulting in a decrease in pressure at that point and an increase in the velocity of the fluid. In the context of the Dassault Falcon 2000LXS, the air conditioning system utilizes this principle to enhance airflow, particularly when the aircraft is on the ground and other sources of airflow may not be available or effective.

This effect allows the two engines to create a natural airflow through the air conditioning system, ensuring that cabin ventilation and temperature control can occur even when the engines are not operating at high thrust, as would typically be the case during taxi or while stationary on the tarmac. Utilizing the Venturi effect is an efficient way to maintain cabin comfort without needing to rely solely on powered systems.

The other options involve different functionalities or scenarios that do not directly contribute to ground airflow for the AC system in the same manner. For instance, the ECU control may manage various systems aboard the aircraft but does not specifically create airflow. APU assist refers to the Auxiliary Power Unit's role in powering systems but does not involve the principle of airflow generation like the Venturi