Cavitation in a water pump 

Cavitation cannot be called a silent killer: it has quite audible signs. In spite of that we are facing serious consequences (eg. missing blades, thinned shaft) during maintenance only many times. This type of failure can be quickly identified during a routine vibration measurement, e.g. based on a saturated vibration spectrum (see below). Usually there could be enough time left to eliminate the root causes as well. Thanks to the illustrative video, we can also recognize how easy is to fix the source of fault in some cases.
Source of video: BTCInstrumentation