Cleaning & Corrosion Control Flashcards
Identify the areas of an aircraft that are most prone to corrosion.
Battery compartment, exhaust system and exhaust trails, wheel wells, lower area of the belly (bilge), piano hinges, areas of dissimilar metal contact, welded areas, inside of fuel tanks especially integral tanks, metal fittings and under high stress, lavatories and foodservice areas.
Where is filiform corrosion most likely to occur on an aircraft?
Under a dense coating of topcoat enamel such as polyurethane. Filiform corrosion is caused by improperly cured primer.
Where is fretting corrosion most likely to occur on an aircraft?
In a location where there is a slight amount of relative movement between two components, and no way for the corrosive residue to be removed as it forms.
Where is intergranular corrosion most likely to occur on an aircraft?
Along the grain boundaries of aluminum alloys that have been improperly heat-treated. Extruded aluminum alloy is susceptible to intergranular corrosion.
Where is dissimilar metal corrosion most likely to occur on an aircraft?
Anywhere different types of metal come in contact with each other, especially where moisture is present.
Where is stress corrosion most likely to occur on an aircraft?
In any metal component that is continually under a tensile stress. The metal around holes in castings that are fitted with pressed-in bushings are susceptible to stress corrosion.
What must be done to a piece of aluminum alloy to remove surface corrosion and to treat the metal to prevent further corrosion?
Remove the corrosion residue with a bristle brush or a nylon scrubber. Neutralize the surface with chromic acid or with some type of conversion coating. Protect the surface from further corrosion with a coat of paint.
What is used to keep corrosion from forming on structural aluminum alloy?
An oxide coating or aluminum cladding.
How may rust be removed from a highly stressed metal part?
By glass bead blasting, by careful polishing with mild abrasive paper or by using fine buffing compound on a cloth buffing wheel.
How should corrosion be minimized at piano hinges?
They should be kept as clean and dry as practicable and lubricated with a low viscosity moisture dispersing agent.
What tools are proper for removing corrosion from aluminum alloy?
Aluminum wool or aluminum wire brushes. Severe corrosion can be removed with a rotary file.
What is used to clean transparent plastic windshields and windows of an aircraft?
Mild soap and plenty of clean water.
What is used to neutralize the electrolyte from a lead-acid battery that has been spilled on an aircraft structure?
A solution of bicarbonate of soda and water.
What is used to neutralize the electrolyte from a nickel-cadmium battery that has been spilled on an aircraft structure?
A solution of boric acid and water, or vinegar.
What solvent is recommended for removing grease from aircraft fabric prior to doping it?
Methyl Ethyl Ketone (MEK) or lacquer thinner.
