When performing an initial AC test, which of the following actions is permissible?

Maintaining AC supply during an initial AC test is crucial for several reasons. The AC supply is necessary to ensure that the electrical systems within the aircraft are operational and can be accurately assessed. By keeping the AC supply active, it allows for the verification of power distribution to essential systems, enabling pilots and technicians to confirm that everything is functioning correctly before further actions or tests are conducted.

It's important to note that other actions may disrupt the test. For example, running any hydraulic pump could lead to unexpected system interactions that may complicate the test results. Cycling FCM panel switches might cause unnecessary fluctuations or changes in system status, complicating the assessment. Powering down the system would negate the test entirely, as it would not allow for the evaluation of the AC systems when they are intended to be operational. Maintaining the AC supply ensures a stable environment for testing and aids in the identification of potential issues effectively.