General: Materials & Processes 🔊

Question 1

What is a suitable non-destructive testing method for detecting surface cracks on aluminum castings and forgings?

Answer 1

Dye penetration, it detects surface cracks with equal success on aluminum, magnesium, brass, copper, and titanium.

Question 2

List the steps in a dye-penetrant inspection.

Answer 2

1. Thoroughly clean the materials surface
2. Apply the penetrant for the specified dwell time
3. Remove the penetrant with water or emulsifying cleaner
4. Dry the part
5. Apply the developer
6. Inspect the results

Question 3

What is the procedure for performing a magnetic particle inspection?

Answer 3

Thoroughly clean all grease oil and dirt from the metal part which must be a ferrous material. Magnetize the part then apply the ferromagnetic particles, either liquid or dry powder. If discontinuity is present, the magnetized particles will form a pattern in the approximate shape of the discontinuity.

Question 4

What are the two types of self-locking nuts?

Answer 4

All metal and fiber lock or elastic stop nuts

Question 5

What is the general rule for using self-locking nuts?

Answer 5

Do not use them at joints which are subject to rotation

Question 6

What type of cable is used in primary control systems?

Answer 6

Extra flexible 7x19 cable

Question 7

How can correct grip length of a bolt be determined?

Answer 7

The grip length, or unthreaded portion of the bolt shank, should be the total thickness of the material being joined

Question 8

The length of AN standard bolts are measured in what fraction?

Answer 8

8ths of an inch

Question 9

What does the triangle mean on the head of a steel bolt?

Answer 9

Close tolerance

Question 10

What numbers are used for close tolerance bolts?

Answer 10

AN-173 through AN-186 for hex head bolts; NAS-80 through NAS-86 for countersunk bolts

Question 11

What is the difference between a standard bolt and a close tolerance bolt?

Answer 11

A closed tolerance bolt is machined to more precise dimensions and used in high performance applications

Question 12

What fraction is used to measure solid rivet diameter?

Answer 12

32nds of an inch

Question 13

Describe a rivnut.

Answer 13

A threaded body that is expanded to the aircraft structure

Question 14

What is the purpose of a channel nut or nutplate?

Answer 14

Both allow a screw or bolt to be installed without needing to hold a nut with a wrench

Question 15

What are common materials for cotter pins to be made from?

Answer 15

Low carbon steel or stainless steel

Question 16

What is the smallest cable that can be used in primary control systems?

Answer 16

⅛ inch diameter

Question 17

What should be the depth of penetration when making a fillet weld?

Answer 17

25% to 50% of the thickness of the base metal

Question 18

What precision measuring instruments are used to measure outside dimensions?

Answer 18

Outside micrometers and Vernier calipers

Question 19

What term describes a metal that is based in iron?

Answer 19

Ferrous alloy

Question 20

What should be the width of the weld bead and depth of penetration when making a butt weld?

Answer 20

3 to 5 times the thickness of the base metal with 100% penetration

Question 21

What system is used to identify AN type aircraft bolts?

Answer 21

They have code markings on the bolt heads for identification. Diameter is measured in 16ths of an inch and length in 8ths of an inch.

Question 22

What is the difference between close tolerance and regular AN bolts?

Answer 22

Close tolerance bolts are used in applications where the joint is subjected to severe vibrations and load reversals.

Question 23

What are the steps for solution heat treating aluminum alloys?

Answer 23

Must be heated to a predetermined temperature, heat soaked for a specific period, then rapidly quenched to a relatively low temperature.

Question 24

In what state is aluminum alloy immediately after solution heat treating and quenching?

Answer 24

Comparatively soft state so it must be naturally aged or precipitation hardened.

Question 25

What is done to prevent certain aluminum alloy rivets (D and DD) from becoming hard after heat treating and quenching?

Answer 25

They are stored in a refrigerator at temperatures lower than 32°f. They will remain soft for several days. (ice box rivets)

Question 26

What do rivet head markings indicate?

Answer 26

Alloy of the rivet

Question 27

Why is alloy steel that is responsive to heat treatment usually less suitable for welding?

Answer 27

It has a tendency to become brittle and lose its ductility around the weld

Question 28

Why should steel be normalized after welding or machining?

Answer 28

To remove internal stress of the metal, reducing the brittleness

Question 29

What are two methods of case hardening?

Answer 29

Carburizing and nitriding

Question 30

What are the characteristics of a cold weld?

Answer 30

Improper penetration and cold laps caused by insufficient heat. They appear rough and irregular with edges not feathered into the base metal.

Question 31

What tools are used to measure the outside diameter of shafts, thickness of sheet metal stock, diameter of drills, and other similar applications?

Answer 31

Outside micrometer or caliper

Question 32

What should be used to make a visual inspection of a weld?

Answer 32

At least 10x magnifying glass

Question 33

Name some types of non-destructive testing used on non-ferrous materials.

Answer 33

Eddy current, dye-penetrant, x-ray, coin tap, and visual

Question 34

What is the most common type of corrosion?

Answer 34

Surface corrosion

Question 35

What does a ¼-20 bolt mean?

Answer 35

Bolt diameter and thread count

Question 36

Why should a micrometer be periodically calibrated?

Answer 36

Ensure accuracy

Question 37

What fraction is used to measure a solid rivet’s length?

Answer 37

16ths of an inch

Question 38

What are some types of washers used on aircraft?

Answer 38

Spring lock, flat, lock tooth, tab, finished

Question 39

What is an SDS?

Answer 39

Safety Data Sheet

Question 40

What class bolts are used on aircraft?

Answer 40

Class 3 bolts

Question 41

What class threads are used on aircraft?

Answer 41

Class 3 threads