Final answer:
To adjust the pressure on a Beta-Freightliner R-12 during defueling, one must interact with the pressure control panel, typically by pressing a button or turning a knob to regulate the pressure valve; however, consulting the specific operator's manual is crucial for the correct procedure.
Step-by-step explanation:
When defueling an aircraft using a Beta-Freightliner R-12 mobile defueling unit, precise control of the pressure is essential to maintain a steady flow rate of the fuel being extracted. To adjust the pressure to the desired level on a Beta-Freightliner R-12, you would typically interact with the pressure control panel.
This often includes pressing a button or turning a knob that regulates the pressure valve, though the exact control mechanism can vary based on the model and configuration of the equipment. It is important to refer to the specific operator's manual for the unit you're working with to ensure proper defueling procedures are followed and to identify the exact controls for pressure adjustment.