Which of the following is not a function of the master switch?

The master switch is primarily responsible for controlling the electrical systems within the aircraft, which includes activating avionics and conducting battery tests. It serves as a central point that manages the flow of electrical power to various components, ensuring they can operate as needed.

In the context of shutting down the engine, this action is not directly handled by the master switch. Instead, engine shutdown typically involves throttling back the power and using the appropriate engine control mechanisms rather than merely flipping a switch. This process usually requires specific procedures to ensure that the engine is safely and properly shut down, which may include actions such as fuel cutoff and ignition system disengagement. Hence, while the master switch plays a crucial role in managing electrical systems, shutting down the engine itself does not fall under its functions.