The Main, Scavenge, and Transfer ejectors are powered by what?

The Main, Scavenge, and Transfer ejectors in the PSA Airlines Canadair Regional Jet Systems utilize motive flow pressure for their operation. This type of system relies on the principle of utilizing high-pressure fluid to create a suction effect that moves other fluids, such as fuel or oil, through the ejectors.

Motive flow pressure is generated by the flow of a primary fluid (usually in the form of fuel or oil) that creates a low-pressure area, thus enabling a secondary fluid to flow into the ejector system. This method is efficient in managing fluid movement within the aircraft's systems without requiring additional mechanical components, thereby simplifying the design and reducing weight.

In contrast, electrical systems and hydraulic pressure do not play a role in the function of these specific ejectors, as the operation is fundamentally reliant on the aerodynamic and fluid dynamics principles associated with motive flow. Gravity flow is also not applicable for the Main, Scavenge, and Transfer ejectors since these systems are designed to function actively with pressurized flow rather than passively relying on gravity.