What is the primary function of the PIU?

The primary function of the Pitch Change Mechanism (PIU) is to regulate the oil pressure that is delivered to the propeller's pitch change mechanism. This is essential for controlling the pitch of the propeller blades, which in turn affects the aircraft's performance characteristics, such as thrust and speed. By varying the pitch, the PIU helps optimize the efficiency of the propeller across different flight phases, ensuring that the engine operates effectively within the required performance parameters.

The functioning of the PIU is crucial because it directly influences the overall propeller functionality. A propeller's pitch adjustment is fundamental to achieving the desired thrust level and maintaining optimal engine efficiency. In this context, while controlling propeller pitch is related to the PIU, it is the regulation of oil pressure that is specifically its primary function, as it enables the pitch adjustments to occur.

Other options, while relevant to aircraft performance, do not directly describe the primary function of the PIU. For instance, measuring fuel efficiency is typically the responsibility of fuel flow monitoring systems, while monitoring engine RPM involves engine instruments that track rotational speed but do not directly engage with the propeller's pitch. These other aspects contribute to the overall performance management of the aircraft but do not define the specific function of