Questions | Aircraft Cleaning and Corrosion Control

Fill in the Blanks

1. ________________ is the process of removing contaminants like dirt, oil, and salt from aircraft surfaces.

2. ________________ corrosion occurs evenly across a surface due to prolonged exposure to moisture and chemicals.

3. High-pressure washing is an effective method for cleaning large areas but may risk ________________ damage if not used properly.

4. The application of ________________ coatings can help protect aircraft surfaces from corrosion by providing a barrier against environmental factors.

5. ________________ corrosion is often seen when dissimilar metals are in contact and exposed to an electrolyte.

6. To prevent corrosion, aircraft maintenance includes regularly checking for signs of ________________ and applying appropriate ________________.

7. ________________ cleaning uses chemicals that dissolve contaminants to effectively clean aircraft parts.

8. ________________ alloys are commonly used in aircraft due to their resistance to corrosion and lightweight properties.

9. ________________ primers, which contain zinc, are used to provide sacrificial protection against corrosion.

10. The ________________ specification defines the requirements for corrosion inhibitors used in military aviation.

11. Scheduled maintenance and cleaning help to ensure proper ________________ systems are functioning correctly.

12. ________________ corrosion occurs at the grain boundaries of metal alloys, often due to improper heat treatment.

13. The use of ________________ waves in a cleaning solution can remove contaminants from intricate parts without physical contact.

14. Regulations from the ________________ define the standards for aircraft maintenance and cleaning practices in the United States.

15. ________________ coatings are often phased out due to environmental regulations but provide excellent corrosion resistance.

16. The ________________ of contaminants from aircraft surfaces is critical for preventing corrosion and maintaining performance.

17. ________________ cleaning involves using a combination of brushes and cloths to manually remove contaminants.

18. Proper ________________ is essential to prevent water accumulation in aircraft parts, which can lead to corrosion.

19. The ________________ provides guidelines for aircraft maintenance practices in Europe, including corrosion control.

20. ________________ control procedures include applying protective coatings and regularly inspecting for signs of deterioration.

TRUE or FALSE

1. Scheduled maintenance is necessary only when visible signs of corrosion are detected. TRUE/FALSE

2. Epoxy coatings provide a durable layer that resists corrosion and environmental damage. TRUE/FALSE

3. High-pressure washing is suitable for cleaning all types of aircraft surfaces, including delicate components. TRUE/FALSE

4. SAE AMS standards provide specifications for materials and practices related to corrosion control in aerospace applications. TRUE/FALSE

5. Ceramic coatings are used primarily for their protective properties rather than aesthetic appeal. TRUE/FALSE

6. Corrosion control involves only applying protective coatings and does not include regular maintenance. TRUE/FALSE

7. Chemical cleaning agents should be used with consideration of their environmental impact. TRUE/FALSE

8. Intergranular corrosion is less severe than pitting corrosion. TRUE/FALSE

9. The main goal of aircraft cleaning is to improve the aircraft's appearance. TRUE/FALSE

10. High-pressure washing is effective for cleaning sensitive electronic components on an aircraft. TRUE/FALSE

11. Regular inspections can help detect early signs of corrosion. TRUE/FALSE

12. Ultrasonic cleaning is effective for cleaning intricate parts with complex geometries. TRUE/FALSE

13. Uniform corrosion affects only specific areas of the aircraft surface. TRUE/FALSE

14. Regular application of protective coatings is a preventive measure against corrosion. TRUE/FALSE

15. Aircraft cleaning schedules are typically based on the manufacturer's recommendations and operational conditions. TRUE/FALSE

16. Galvanic corrosion is most common in areas where different metals are joined together. TRUE/FALSE

17. Aircraft cleaning procedures must comply with industry standards to ensure safety and effectiveness. TRUE/FALSE

18. Manual cleaning is often used for detailed cleaning in hard-to-reach areas. TRUE/FALSE

19. Environmental regulations have no impact on the choice of cleaning agents used in aircraft maintenance. TRUE/FALSE

20. Corrosion control is only necessary for external aircraft surfaces exposed to the elements.TRUE/FALSE

Knowledge Application

1. What are the common types of corrosion found on aircraft?

2. Identify the areas of an aircraft that are most prone to corrosion.

3. Where is filiform corrosion most likely to occur on an aircraft?

4. Where is fretting corrosion most likely to occur on an aircraft?

5. Where is intergranular corrosion most likely to occur on an aircraft?

6. Where is dissimilar metal corrosion most likely to occur on an aircraft?

7. Where is stress corrosion most likely to occur on an aircraft?

8. What must be done to a piece of aluminum alloy to remove surface corrosion and to treat the metal to prevent further corrosion?

9. What is used to keep corrosion from forming on structural aluminum alloy?

10. How may rust be removed from a highly stressed metal part?

11. How should corrosion be minimized at piano hinges?

12. What tools are proper for removing corrosion from aluminum alloy?

13. What is used to clean transparent plastic windshields and windows of an aircraft?

14. What is used to neutralize the electrolyte from a lead-acid battery that has been spilled on an aircraft structure?

15. What is used to neutralize the electrolyte from a nickel-cadmium battery that has been spilled on an aircraft structure?

Multiple Choices

1. A primary reason why ordinary or otherwise nonapproved cleaning compounds should not be used when washing aircraft is because their use can result in
a. hydrogen embrittlement in metal structures.
b. hydrogen embrittlement in nonmetallic materials.
c. a general inability to remove compound residues.

2. How may magnesium engine parts be cleaned?
a. Soak in a 20 percent caustic soda solution.
b. Spray with MEK (methyl ethyl ketone).
c. Wash with a commercial solvent, decarbonize, and scrape or grit blast.

3. When an anodized surface coating is damaged in service, it can be partially restored by
a. applying a thin coat of zinc chromate primer.
b. chemical surface treatment.
c. use of a suitable mild cleaner.

4. For which of the following reasons would a water break test be conducted?
a. To make certain that a newly alodized aluminum surface is sufficiently coated.
b. To make certain that a bare metal surface is thoroughly clean.
c. To make certain that an anodizing coating has been sufficiently removed before an electrical bonding connection can be made.

5. Select the solvent recommended for wipedown of cleaned surfaces just before painting.
a. Aliphatic naptha.
b. Dry-cleaning solvent.
c. Aromatic naptha.

6. Nickel-cadmium battery cases and drain surfaces which have been affected by electrolyte should be neutralized with a solution of
a. boric acid.
b. sodium bicarbonate.
c. potassium hydroxide.

7. Which of the following are acceptable to use when utilizing chemical cleaning agents on aircraft?
1. Synthetic fiber wiping cloths when using a flammable agent.
2. Cotton fiber wiping cloths when using a flammable agent.
3. Atomizing spray equipment.

a. 2 and 3.
b. 1.
c. 2.

8. Select the solvent used to clean acrylics and rubber.
a. Aliphatic naphtha.
b. Methyl ethyl ketone.
c. Aromatic naphtha.

9. Fayed surfaces cause concern in chemical cleaning because of the danger of
a. forming passive oxides.
b. entrapping corrosive materials.
c. corrosion by imbedded iron oxide.

10. Caustic cleaning products used on aluminum structures have the effect of producing
a. passive oxidation.
b. improved corrosion resistance.
c. corrosion.

11. Fretting corrosion is most likely to occur
a. when two surfaces fit tightly together but can move relative to one another.
b. only when two dissimilar metals are in contact.
c. when two surfaces fit loosely together and can move relative to one another.

12. The rust or corrosion that occurs with most metals is the result of
a. a tendency for them to return to their natural state.
b. blocking the flow of electrons in homogenous metals, or between dissimilar metals.
c. electron flow in or between metals from cathodic to anodic areas.

13. Which of the following are the desired effects of using Alodine on aluminum alloy?
1. A slightly rough surface.
2. Relieved surface stresses.
3. A smooth painting surface.
4. Increased corrosion resistance.

a. 3 and 4.
b. 1, 2, and 4.
c. 1 and 4.

14. Which of the listed conditions is NOT one of the requirements for corrosion to occur?
a. The presence of an electrolyte.
b. Electrical contact between an anodic area and a cathodic area.
c. The presence of a passive oxide film.

15. The lifting or flaking of the metal at the surface due to delamination of grain boundaries caused by the pressure of corrosion residual product buildup is called
a. brinelling.
b. granulation.
c. exfoliation.

16. A nonelectrolytic chemical treatment for aluminum alloys to increase corrosion resistance and paint-bonding qualities is called
a. anodizing.
b. alodizing.
c. dichromating.

17. Which of the following are acceptable to use in cleaning anodized surfaces?
1. Steel wool.
2. Brass wire brush.
3. Aluminum wool.
4. Stainless steel wire brush.
5. Fiber bristle brush.

a. 1, 3, & 5.
b. 2 & 4.
c. 3 & 5.

18. Intergranular corrosion in aluminum alloy parts
a. may be detected by surface pitting, and white, powdery deposit formed on the surface of the metal.
b. commonly appears as threadlike filaments of corrosion products under a dense film of paint.
c. cannot always be detected by surface indications.

19. Which of the following may not be detectable even by careful visual inspection of the surface of aluminum alloy parts or structures?
a. Filiform corrosion.
b. Intergranular corrosion.
c. Uniform etch corrosion.

20. What may be used to remove corrosion from highly stressed steel surfaces?
a. Steel wire brushes.
b. Fine-grit aluminum oxide.
c. Medium-grit carborundum paper.

21. A primary cause of intergranular corrosion is
a. improper heat treatment.
b. dissimilar metal contact.
c. improper application of primer.

22. Corrosion should be removed from magnesium parts with a
a. stiff, nonmetallic brush.
b. silicon carbide brush.
c. carborundum abrasive.

23. Why is it important not to rotate the crankshaft after the corrosion preventive mixture has been put into the cylinders on engines prepared for storage?
a. Fuel may be drawn into one or more cylinders and dilute or wash off the corrosion preventive mixture.
b. The seal of corrosion preventive mixture will be broken.
c. Engine damage can occur from hydraulic lock.

24. Which of the following is an acceptable first step procedure to help prevent scratching when cleaning a transparent plastic surface?
a. Gently wipe the surface with a clean, dry, soft cloth.
b. Flush the surface with clean water.
c. Gently wipe the surface with a clean, soft cloth moistened with de-mineralized or distilled water.

25. What should be done to prevent rapid deterioration when oil or grease come in contact with a tire?
a. Wipe the tire thoroughly with a dry cloth, and then rinse with clean water.
b. Wipe the tire with a dry cloth followed by a washdown and rinse with soap and water.
c. Wipe the tire with a cloth dampened with aromatic naphtha and then wipe dry with a clean cloth.

Aircraft cleaning and corrosion control questions and answers

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