Vacuum pump

Originally posted by Pat Schmitz
For what it's worth -

The dry pumps have a carbon graphite based material used for the pump vanes. The graphite is designed to be self lubricating, and is in fact designed to wear away gradually over time.... predictable enough wear rate that they know roughly when they should be about worn out...

Quite right! If the pumpe suddenly stops because of broken torque link and you have no airfilter between pump and avionics, then the carbon graphite dust will be sucked into your avionics.

From then on, you can count the time for overhaul of suction driven devices in your avionics.

Had this seen in several planes, recommend this cheap filter anyway.