Fuel pump noise

[Sender46]

When the fuel pump is running I can hear the noise of the pump but there is also a higher pitched whining noise with it that fades in and out about every 3 seconds. Does anybody know if that is realistic?

[Sender46]

I've just watched a video of the Just Flight PA-28 for P3D. The fuel pump for that aircraft made a continuous noise, unlike the variable noise in the MSFS version.

Is it intentional that the fuel pump sound for the MSFS version includes a higher pitch noise fading in and out? Not a big issue but I like realism and I guess I'm curious more than anything. Feedback from anybody that knows whether this is realistic would be welcome.