A-6a Assignment A-1

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Unit A-6a Theory Assignment

Issue A – September 2006 Revision 1 Page 1of 27

Name ……………………..….………………

Student No………………………...…………

THEORY ASSIGNMENT PAPER

A-6a BASIC AIRCRAFT MATERIALS & CORROSION

Topic – 1,2,3,4,5 & 6

Number of Questions: 92

Question Format: Written Response

Instructions:

1. For this assignment you will follow all directions from your instructor. 2. Attempt all questions. 3. All answers require a reference of the figure (if Applicable) and page

number. 4. Mark your responses in black or blue biro only. 5. Ensure your name and student number is completed on the Assignment

paper. 6. There is no time limit attached to this Assignment.

Example:

Question 1 A10a 1.1

What is the method called that requires you to remove metal in the repair of damaged compressor stator blades?

Ans Blending

Ref Jeppesen Power Pg 4-34

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Topic 1 Aircraft Materials – Ferrous 5

Topic 2 Aircraft Materials – Non-Ferrous 11

Topic 3 Aircraft Materials – Composite / Non-Metallic 15

Topic 4 Corrosion 21

Topic 6 Pipes, Hoses and Unions 23

Topic 1 – Aircraft Materials – Ferrous

1. What does the acronym (SAE) stand for?

2. What substance is used to make steel?

3. What do the numbers in the SAE numbering identify?

4. What are some of the more common alloying agents used in steel?

5. Why is carbon added to steel?

6. How much carbon do low carbon steels contain and where are low carbon steels primarily used?

7. Which type of steel contains between 0.30% and 0.50% carbon, accepts heat treatment well, and is especially adaptable for machining or forging?

8. Where is high carbon steel primarily used?

9. What effect does chromium have on steel and where are chromium steels used?

10. What properties do would nickel steels have, and where are they used on aircraft?

11. What characteristics do Nickel-Chromium steels possess, and where would they be used?

12. In what applications is the strength and corrosion resistance of stainless steels best suited to?

13. What characteristics do molybdenum steels have and where are they used?

14. Identify the three types of stainless steel and their properties?

15. Why is sulphur removed from steel?

16. If sulphur can not be removed from steel, how can it’s affects be nullified?

17. What properties does silicon bring to an alloy steel?

18. What affect does phosphorous have on steel?

19. What other metal is vanadium combined with to produce a strong, tough, ductile steel alloy?

20. What characteristic does tungsten have on steel, and where are tungsten steels used?

21. Why are steels annealed and what properties does it have after treatment?

22. What is one of the most important reasons for normalizing steel in aircraft structures?

23. Why are steels tempered?

24. Explain the hardening process of alloy steels?

25 What is the reason for case hardening steel?

26. Explain the following? Carburising

Nitriding

27. Name 2 types of hardness testing and the difference between them?

28. Explain tensile strength testing?

29. Explain fatigue strength testing?

30. Explain impact resistance testing?

Topic 2 – Aircraft Materials – Non-Ferrous 1. How is aluminium alloy classified?

2. What does the first digit identify in the four-digit index system for aluminium alloys?

3. What does the second digit identify in the four-digit index system for aluminium alloys?

4. What do the last two digits in the 1XXXX group of alloys indicate?

5. What do the last two digits in the 2XXXX to 8XXXX group of alloys indicate?

6. Name the major alloying elements in the following group of alloys, and the properties of these groups? 1xxx

7. Identify the alloys present in 7075 Aluminium alloy and their percentages.

8. What is Alclad?

9. What is the thickness of Alclad coating?

10. What is the purpose of heat treatment?

11. Name and explain the two types of heat treatment used on aluminium alloys?

12. What do the following numbers mean in relation to heat treatment? -T

13. What term is used to describe the situation when an alloy is allowed to cool at room temperature following heat treatment?

14. Define annealing.

15. Which alloy has a solution heat treatment temperature of 870°F.

16. Give another two terms for strain hardening.

17. How is magnesium obtained?

18. When compared to aluminium, how much does magnesium weigh?

19. What benefits are gained by solution heat treating magnesium alloys?

20. What is the designation for the alloying element zirconium.

21. Name and describe the three classifications for Titanium.

22. Name and describe the two nickel alloys that can be found in aircraft?

23. Where in an aircraft is copper to be found?

Topic 3 – Aircraft Materials – Composite / Non-Metallic

1. Describe the following composite fibres? Glass

Aramid

Carbon / Graphite

2. Describe the following resin systems? Polyester

3. Explain the following adhesives? Resin

4. Why is it important to place layers of fibre in the correct orientation?

5. State the warp direction on a roll of fabric?

6. In which direction do the fill/weft threads run in a roll of fabric?

7. Define bias in relation to fabric orientation?

8. Describe the following styles that fibres are available in? Unidirectional

Bi-directional

9. Explain the following common weave patterns? Plain

10. Define “pot life”.

11. Describe pre-pregs?

12. What type of inspection method is the most frequently used method for inspecting composites?

13. What must an operator have a good knowledge of, before commencing a tap testing inspection?

14. What is tap testing good at detecting?

15. What are the two main methods of ultrasonic inspection?

16. What is ultrasonic inspection useful for?

17. In relation to honeycomb core composites, what is radiography (X-ray) useful at detecting?

18. How does thermography detect flaws in composite components?

19. Why is it inadvisable to use dye penetrant inspection on composite components?

20. Explain the process of differentiating between transparent plastic materials?

21. List some basic storage and handling requirements for transparent thermoplastic sheets.

22. What must be done before heating any transparent plastic?

23. Explain the following repairs? Step cut

Potted repair

Injection

24. Explain how the following materials are cut? Fibreglass

Carbon / graphite

Aramid

Pre-preg

25. What problems can arise when drilling and machining composite fibres?

26. Explain heat curing?

27. Explain the following pressure applications? Compression molding

Vacuum bag

Topic 4 – Corrosion

1. Explain the following types of corrosion? Dry

Direct Chemical

Electrochemical

Galvanic

Dissimilar Metal

Surface

Intergranular

Stress

Filiform

Fretting

Exfoliation

Microbiological

2. Explain the effects on corrosion with differing sized anodes and cathodes, and if the metals are close or far apart on the electrochemical scale ?

3. Explain the corrosion tendencies towards each other of stainless steel, magnesium and aluminium alloys in relation to the electrochemical scale?

Topic 6 – Pipes, Hoses and Unions

1. What Do the markings on the lower piece of tube indicate?

2. How are flared fittings identified?

3. Explain the colour coding of flared fittings?

4. Explain the use of flareless fittings?

5. Explain the use of beading?

6. What 4 materials are used for the construction of the inner liner of a flexible line?.

5052-O 0.028” wall OD 0.250”

7. Explain the construction and associated pressures associated with the following flexible lines? Low pressure :

Medium pressure :

High Pressure :

8. Explain flexible line identification?

9. Explain the different types of end fittings used on flexible lines?

A-6a Assignment A-1

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