Filters and Air Driers

Filters and Air Driers

Before installing a cartridge type of filter unit the cartridge and casing should be inspected for signs of damage and also to ensure freedom from dirt and other foreign matter.

In some unit designs the case is made of rubber and for this reason it may have been stored in French Chalk. Before fitting the cartridge into this type of case, all traces of chalk must be removed by lightly brushing the rubber with a suitable cleaning agent as recommended in the relevant Aircraft Maintenance Manual.

In some installations, air driers are of the type which utilises Silica Gel Crystals as drying media. Before installation, the units should be detached and charged with a fresh quantity of Silica Gel Crystals. After installation, a check should be made to ensure that the inspection windows, where provided, are readily visible.

When installing baffle-type air driers, it must be ensured that the sealant necessary for fixing is of the correct type and is correctly applied to the appropriate area of the fuselage skin and air drier casing.

After installation, the connections between the filters, air driers and all appropriate pressure sensing lines must be securely made and leak-tested in the manner described in the relevant Aircraft Maintenance Manual.