Materials and processes

Question 1

Which steel alloy is noted for its toughness and is most commonly used for aircraft structure, frame members, engine mounts, landing gear parts and other structural parts?

Answer 1

Chrome molybdenum steel

Question 2

How is work hardening metal obtained?

Answer 2

By cold working the metal

Question 3

Which casehardening process is accomplished on steel alloys, after heat treating, to produce a wear resistant surface on engine parts, such as crankshafts?

Answer 3

Nitriding

Question 4

What portable hardness test is commonly used for testing aluminum alloys, copper, brass or other relatively soft materials?

Answer 4

Bracol tester

Question 5

What class of thread are aircraft bolts commonly manufactured?

Answer 5

Class 3, medium fit

Question 6

How may AN standard steel bolts be identified?

Answer 6

By the code markings on the bolt head

Question 7

What is the grip length of a bolt?

Answer 7

The unthreaded portion of the bolt

Question 8

What is the difference between a general purpose bolt and a close tolerance bolt?

Answer 8

Close tolerance bolts are machined to more accurate dimensions than general purpose bolts

Question 9

Where may self-locking nuts not be used

Answer 9

At joints which either the nut or bolt are subject to rotation

Question 10

How can the recommended torque for a bolt or nut be determined when torque values are not called out in the maintenance procedures?

Answer 10

Use the information contained in the standard torque table such as in the AC 43.13-1B

Question 11

What do the markings on the heads of solid shank rivets indicate?

Answer 11

The material of which they are made and their strength

Question 12

What may be accomplished to prevent heat treated aluminum alloy rivets from becoming hard after the quenching process?

Answer 12

Store them in a freezer

Question 13

What type of cable is commonly used in primary control systems?

Answer 13

Extra flexible 7x19 stainless steel cable

Question 14

When performing a penetrant inspection, what happens when the penetrant is applied and removed from a part that is cracked?

Answer 14

The penetrant liquid enters the crack and remains there in order to make the crack visible when developer is applied

Question 15

What is the procedure for performing a dye penetrant inspection?

Answer 15

Clean the surface, apply the penetrant, remove the penetrant with an emulsifier or cleaner, dry the are, apply the developer and interpret the results

Question 16

What NDT methods could be used for detecting surface cracks in aluminum fittings?

Answer 16

Dye penetrant, x-ray, ultrasonic, eddy current and visual inspection

Question 17

Which NDT method can be performed without removing the surface coatings such as primer, paint and anodized films?

Answer 17

Eddy current

Question 18

Name some tools that are commonly used to assist in making visual inspections of welds

Answer 18

A magnifying glass, a flashlight, a mirror and possibly a borescope

Question 19

What does the magnetic particle inspection process consist of?

Answer 19

The basic process consists of magnetizing a part and the applying ferromagnetic particles to the surface area to be inspected. If a defect is present, the particles will form a pattern on the surface

Question 20

What are the penetration requirements for a fillet weld?

Answer 20

Should be 25-50% of the thickness of the base metal

Question 21

What width should welding beads have and what should be the depth of penetration of a butt weld?

Answer 21

Should be 3-5 times the thickness of the base metal and 100% penetration

Question 22

What type of precision measuring instruments can be used to measure the outside dimensions of aircraft parts?

Answer 22

Outside micrometers and vernier calipers

Question 23

Why should a micrometer be periodically calibrated?

Answer 23

To assure its accuracy

Question 24

What is the main difference between thermoplastic and thermosetting resins?

Answer 24

Thermoplastic is softened by heat and thermosetting does not soften with heat

Question 25

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

Answer 25

Because of its tendency to become brittle and lose its ductility in the welded area

Question 26

What are some of the purposes for which thermoplastic and thermosetting resins are commonly used in modern aircraft?

Answer 26

Thermoplastic is used for windows and windshields and thermosetting is used as matrix material in composite structures

Question 27

Name one material commonly used as the reinforcing component in structural composite laminates

Answer 27

Aramid (Kevlar), fiberglass and graphite or carbon fiber

Question 28

Name one substance commonly used as the matrix material in structural composite laminates

Answer 28

Polyester resin and epoxy resin

Question 29

Name one advantage of using prepreg materials over non-prepreg materials in the construction or repair

Answer 29

Prepreg materials have the proper amount of matrix, the reinforcing fibers are completely and evenly permeated with matrix, the matrix has the correct proportions of resin and hardener and they have a lower cost

Question 30

What are the undesirable characteristics of a cold weld?

Answer 30

Improper penetration with rough and irregular cold laps not feathered into the base metal