What must be done after the Fuel Control Unit (FCU) is changed?

After changing the Fuel Control Unit (FCU), the correct next step is to trim the engine. Trimming the engine involves adjusting the engine settings to optimize performance after the installation of a new FCU. Since the FCU plays a crucial role in managing fuel flow and air-fuel mixture, it’s essential to ensure that the engine operates efficiently and within its designated parameters.

The trimming process typically involves fine-tuning the fuel flow and adjusting other parameters to achieve the desired engine performance, stability, and fuel efficiency. It may require monitoring engine performance characteristics like thrust or power output to ensure they align with specifications. Proper trimming is integral to confirming that the new FCU integrates seamlessly with the rest of the engine systems.

Other steps like calibrating fuel flow or checking oil levels are important maintenance tasks but do not directly follow the installation of a new FCU in terms of immediate operational readiness. Resetting the ignition system is unrelated specifically to changes in the fuel control unit.