General cleaning and corrosion oral q

Is there any requirement for cleaning an aircraft prior to an annual or a 100-hour inspection?

Yes, it is a legal requirement as specified in FAR Part 43 Appendix D, in addition to being good common sense.

Discuss the general precautions that should be observed when washing an airplane.

Avoid or protect areas which may be damaged or contaminated, such as pitot and static ports, hinges, sealed areas, and bearings.

What are some of the more common light-duty cleaning agents?

Soap or detergents and water.

What materials are commonly used as heavy-duty cleaners?

Solvents and emulsions.

What are the preferred cleaners for plastic surfaces such as windshields?

Mild soap and water or a manufacturer-approved cleaner.

What type of cleaning agent should be used to remove grease, oil, or fuel from aircraft tires?

Soap and water.

Why should aircraft fabrics and plastics be cleaned only with recommended cleaners?

Recommended cleaners cause the least amount of deterioration or damage.

Give at least three examples of the factors that cause or influence corrosion.

1. The environmental conditions. 2. The presence of dissimilar metals. 3. The type of metal. 4. The presence of electrolytes and/or contaminants. 5. The condition of protective coatings.

Name at least three forms of corrosion.

Surface, intergranular, filiform, dissimilar metal (galvanic), oxidation, pitting, stress, and fretting.

List at least five examples of areas in an aircraft that are prone to corrosion.

Battery compartments, exhaust trail areas, bilge areas, vent areas, landing gear and wheel wells, fuel tanks, wing flap recesses, galleys and laboratories, piano hinges, and any area that can trap water.

Name at least one cause of filiform corrosion.

1. Improper or incomplete curing of a wash primer prior to painting. 2. Failure to completely wash off acidic surface contamination.

What are the visible signs of filiform corrosion?

Blistered paint surfaces or worm or thread-like tracks/patterns under the paint.

What are the two primary factors that may cause development of stress corrosion cracks?

A corrosive environment and sustained tensile stress.

What are the visible signs of fretting corrosion?

The corrosion residue has a dark, smoky appearance and often appears around and streaming back from rivet heads.

Why are piano-type hinges prime spots for corrosion?

The steel pin and aluminum hinges materials are dissimilar metals, and the hinge design tends to trap moisture and contaminants.

What is the best way to protect piano hinges from corrosion?

Keep them clean and properly lubricated.

Provide at least four examples of procedures used to prevent corrosion.

Cleaning, lubrication, treatment (e.g., chemical), sealing, inspection, installing protective covers, and keeping drain holes free and clear.

Describe the tools that should be used to remove corrosion from anodized aluminum surfaces.

Nylon scrubber pads (such as Scotch-Brite), bristle brushes, aluminum wool, or aluminum wire brushes.

Describe the effects of using steel brushes or steel wool to remove corrosion from aluminum surfaces.

Steel brushes or steel wool must not be used to clean aluminum because steel particles can become embedded in the aluminum and can cause corrosion.

What is the purpose of Alodine?

Alodine is a chemical process that deposits a protective film on aluminum alloys. This film improves corrosion resistance and paint adhesion.

For what reason should you avoid cleaning anodized aluminum surfaces with aluminum metal polish?

Aluminum metal polish should not be used on anodized aluminum surfaces because it will remove the protective oxide coating.