[JAG]

I think the system can generally handle a bit of air and would eventually purge through the tank...over time. However, as I highlighted below, air above the reservoir - specifically the suction line to the pump, is not self purging. I learnt this the hard way. Cessna even recognized this and highlights this in the Service Manual. Ensuring you have no air between the reservoir and the pump is essential, and it is simple to remove. It may take a little time to prime that line, but only needs to be rarely.

Jeff