How are the primary jet pump and transfer jet pumps operated?

The primary jet pump and transfer jet pumps in a fuel system are operated by venturi flow from the motive flow line. This principle utilizes the venturi effect, where a fluid's pressure decreases as it flows through a constricted section of pipe, creating a low-pressure area that draws fuel from the tank or other areas into the jet pump.

This operation is essential for maintaining fuel flow and managing fuel distribution without relying on electric or mechanical pumps. By using the dynamics of the fluid itself, these pumps can effectively transfer fuel from where it is stored to where it is needed in the aircraft systems, relying on the pressure differential created by the motive flow.

Thus, the operation of these pumps is a vital aspect of the fuel system, allowing for efficient fuel management in the aircraft’s overall propulsion system.