This test determines the effects on the equipment of prolonged exposure to a salt atmosphere or to salt fog experienced in normal operations.
The main adverse effects to be anticipated are:
Corrosion of metals.
Clogging or binding of moving parts as a result of salt deposits.
Insulation fault.
Damage to contacts and uncoated wiring.
Category S: When the equipment is installed in locations where it is subjected to a corrosive atmosphere in the course of normal aircraft operations, the equipment is identified as Category S and the salt fog test is applicable.
Category T: When the equipment is installed in locations where it is subjected to a severe salt atmosphere, such as equipment exposed directly to external unfiltered air on hovering aircraft that may operate or be parked near the sea, the equipment is identified as category T and the severe salt fog test is applicable…
Apparatus
The apparatus used in the salt fog test shall include the following:
Exposure chamber with racks for supporting test items.
A salt solution reservoir with means for maintaining an adequate level of solution.
A means for atomizing the salt solution, including suitable nozzles and compressed air supply.
A means of heating and controlling chamber temperature.
A means for humidifying the air at temperatures above the chamber temperature.
