In what manner may an FCU be calibrated?

The calibration of a Fuel Control Unit (FCU) must adhere to precise standards to ensure optimal engine performance and efficiency. The correct approach involves using an approved method by the manufacturer, typically on a flow bench, which allows for accurate measurement and adjustment of the FCU's fuel flow characteristics. This process is vital because it ensures that the unit operates within the specified parameters set forth by the manufacturer, taking into consideration variables such as pressure and temperature that can affect fuel flow.

Using a flow bench provides a controlled environment where precise adjustments can be made, and the unit can be tested under different conditions to verify its performance. This method ensures that the calibration is consistent, repeatable, and meets safety and performance standards that are crucial in aviation settings.

Other methods, such as trial and error testing or adjustments during routine maintenance, do not provide the same level of control or reliability and can lead to incorrect calibrations that may affect engine performance or safety. Therefore, relying on a manufacturer-approved calibration procedure is essential for maintaining the integrity and functionality of the FCU.