What is the final step in starting the FADPU?

The final step in starting the Fixed Auxiliary Drive Power Unit (FADPU) is to press the push button. This action is essential as it initiates the operations of the FADPU, allowing it to begin powering the hydraulic systems required for various operations. Pressing the button signifies that all prior preparatory steps—such as securing power to the hydraulic power units (HPUs), opening necessary valves, and ensuring other safety measures—have been correctly completed.

This procedural step is critical as it not only begins the functioning of the FADPU but also ensures that all systems are ready for operation. Other actions, such as opening valves and securing power, are important in establishing the correct operational environment but do not actually start the unit. The pressing of the push button is the definitive action that transitions the equipment from standby to active operational status.