Term
| How may fretting corrosion be identified? |
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Definition
| Pitting of mating surfaces and powdered residue |
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Term
| Why is the aircraft cleaned before inspection? |
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Definition
| Enables the mechanic to properly inspect the aircraft |
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Term
| What is the principle cause of filiform corrosion? |
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Definition
| Improper surface preparation for painting |
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Term
| Why should only recommended cleaners be used on aircraft fabrics or plastics? |
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Definition
| Their use causes less deteriorating effects |
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Term
| What is the most common product used for external wash-down of aircraft engines? |
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Definition
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Term
| Why should aluminum metal polish NOT be used on anodized aluminum surfaces? |
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Definition
| Because it will remove the oxide coat |
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Term
| What type of agent is preferred for cleaning plastic surfaces? |
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Definition
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Term
| How may filiform corrosion be recognized? |
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Definition
| Blistered paint surface and fern-like patterns under paint |
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Term
| What type of aircraft parts are susceptible to stress corrosion? |
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Definition
| Aluminum alloy bell cranks with pressed-in bushings. Landing gear shock struts with pipe-thread type grease fittings. Clevis pin joints. Shrink fits and over-stressed "B" nuts |
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Term
| What are some types of heavy duty cleaning agents? |
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Definition
|
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Term
| What are some types of light duty cleaning agents? |
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Definition
| Soap and synthetic detergents |
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Term
| What general precautions should be used when pressure washing an aircraft? |
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Definition
Avoid or protect areas which maybe damaged or contaminated such as:
Bearings
Hinges
Sealed areas and Painted surfaces |
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Term
| What are the proper tools for removing corrosion from anodized aluminum surfaces? |
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Definition
| Aluminum wool and wire brushes or non-metallic bristle brushes |
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Term
| What are the basic steps of corrosion removal and treatment? |
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Definition
Clean the area
Remove the corrosion
Neutralize the area and restore protective surface |
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Term
| What are the common causes of corrosion? |
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Definition
Environmental conditions
Type of metal
Protective coating and presence of foreign materials |
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Term
| What are some forms of corrosion? |
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Definition
Surface
Stress
Fretting
Dissimilar metal
Intergranular |
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Term
| What is corrosion preventive maintenance? |
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Definition
Inspection
Cleaning
Treatment
Sealing and Lubrication
Protective covers and drain holes |
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Term
| What areas are more prone to corrosion? |
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Definition
Exhaust trails
Battery compartments
Vent openings
Bilge areas
Wheel wells and landing gear
Wing flap recesses and other water entrapment areas |
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Term
| Why are piano-type hinges prime spots for corrosion? |
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Definition
| Because of dissimilar metal contact between the steel pin and aluminum hinge and because of their design, which tends to trap contaminants |
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Term
| How are piano-type hinges protected from corrosion? |
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Definition
| By being kept as clean as possible and properly lubricated |
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Term
| What is Alodine used for? |
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Definition
| Alodine treatment deposits a chemically formed oxide on aluminum alloys to improve corrosion resistance and enhance paint bonding qualities |
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Term
| Is it permissible to use steel wool or steel wire brushes on aluminum surfaces? Explain. |
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Definition
| No, because traces of steel can become embedded in the aluminum and cause corrosion |
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