What are the functions of the digital engine control (DEC) in the Pilatus PC-12 NG?

The digital engine control (DEC) in the Pilatus PC-12 NG plays a crucial role in the overall operation and efficiency of the aircraft's engine. Its primary function is to manage both engine performance and fuel flow automatically, ensuring the engine operates smoothly and efficiently under various conditions and power settings.

By automating these processes, the DEC optimizes fuel injection based on parameters such as altitude, air temperature, and engine load. This automatic management allows for improved performance, fuel efficiency, and engine reliability, as the DEC continuously monitors and adjusts the fuel flow and performance settings in real-time, responding to the flight envelope and operational demands without requiring manual intervention.

In contrast to the other options, which suggest manual control or focus on fuel flow alone, the DEC's automatic management systems enable a level of precision and responsiveness that is essential for safe and effective flight operations. The DEC is not involved in controlling cabin pressure, making it clear that its functions are limited to managing engine-related parameters, reinforcing why the selected answer is accurate.