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, 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 crackshafts?

Answer 3

Nitriding.

Question 4

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

Answer 4

Barcol 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 bolts heads.

Question 7

What is the grip lenght of a bolt?

Answer 7

It is 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 accurately than general bolts.

Question 9

Where may self-locking nuts NOT be used?

Answer 9

At joints which either the nut or bolt 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 become hard after the quenching process?

Answer 12

Store them in a freezer at temp lower than 37°F. They will remain soft for a several days.

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 after developer is applied.

Question 15

What is the procedure for performing a dye penetrant inspection?

Answer 15

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

Question 16

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

Answer 16

Dye penetrant, X-ray, Ulrasonic, Eddy Current, Visual inspection.

Question 17

Which NDT method can be performed wthout 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, flashlight, mirror and, possibly a boroscope.

Question 19

What does the magnetic particle inspection process consists of?

Answer 19

The basics process consists of magnetizing a part and then applying ferromagnetic partices 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 to 50% of the thickness of the base metal.

Question 21

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

Answer 21

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

Question 22

What type of precision measuring instruments can be used to mesure 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 it’s accuracy

Question 24

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

Answer 24

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

Question 25

What is the main difference between Thermoplastic and Thermosetting resins?

Answer 25

Thermoplastic - Softned by heat and become hard when colled down

Thermosetting - Do not soften with heat and will char and burn rather than melt.

Question 26

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

Answer 26

Thermoplastic (Plexiglass) - Windows and Windshields.

Thermosetting- Matrix material in composite structures.

Question 27

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

Answer 27

(1) Aramid - Kevlar
(2) Fiberglass
(3) Graphite.

Question 28

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

Answer 28

(1) Polyester Resin
(2) Epoxy Resin.

Question 29

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

Answer 29

(1) Preprag materials have the proper amount of matrix.
(2) The reforcing fibers are completely and evenly permeated with matrix.
(3) The matrix has the correct proportions of resin and hardener
(4) Low cost.

Question 30

What are the undesirable characteristics of a cold weld?

Answer 30

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