How long will the APU stay online after both engines have started?

The Auxiliary Power Unit (APU) in the Super Hornet is designed to automatically shut down after both engines have been started. The APU will typically remain operational for a period of 60 seconds after engine start to allow for a smooth transition and ensure that all necessary systems are adequately powered during the critical time right after starting the engines. This period is essential for allowing the hydraulic systems, electrical systems, and other components time to stabilize as the aircraft transitions to reliance on its engines. After this duration, the APU will turn off to conserve fuel and minimize wear, as the engines should provide the necessary power for the aircraft's systems.