Materials and Processes
What properties of metal are of primary concern in aircraft maintenance?
1)Hardness 2)Malleability 3)Ductility 4)Elasticity 5)Toughness 6)Density 7)Brittleness 8)Fusibility 9)Conductivity contraction and expansion
Break down part number AN3DD5A
"AN" - Airforce-Navy Bolt "3" indicated the diameter in sixteenths of an inch (3/16) "DD" indicated the type of material (2024 Aluminum Alloy) "5" the length in eights of an inch (5/8) "A" shank is undrilled
Break down AN4-26 rivets
"AN" represent the materials used "4" expressed the diameter of the rivet shank in 32nds of an in. (4/32) "26" expresses the length of the rivet shank in 16ths of an in. (26/16)
Break down AN310D5R Nut
"AN310"- aircraft castle nut "D"-2024-T aluminum alloy "5"-5/16 inch diameter "R"-right hand thread
What is the main purpose of a threaded fastener?
Decrease the time of taking something apart that requires frequent intervals.
What are some common metals used in aircraft?
Magnesium, Aluminum, Titanium, Copper, Manganese, Monel, K monel, Nickel
What is Ferrous and Nonferrous?
Magnetic and Nonmagnetic metals. Iron is the main property
How are most hardware items identified?
Part Number
How long should a standard pigtail be?
1/4 to 1/2 inch 3 to 6 twist minimum
How many classes of fit are there?
4
How many twist per inch for 0.051-0.060
4-9
How many twist per inch for 0.032-0.041
6-11
How many twist per inch for 0.020-0.025
8-14
What are the advantages and disadvantages of control cables?
Advantages: Its strong and light weight. Its flexibility makes it easy to route through the aircraft. Can be set up without backlash. Disadvantages: Tension must be adjusted frequently due to stretching and temperature change
What does AMS mean
Aeronautical Material Specifications
What does AS mean
Aeronautical Standard
What does AN mean
Airforce Navy
What does AND mean
Airforce-Navy design
What does ASTM mean
American Society for Testing Materials
What does ASA mean
American Standard Association
Why is aluminum the most widely used metal in aircraft?
Because of its high strength to weight ratio and its comparative ease of fabrication. Its lightweight, nonmagnetic, an excellent conductor, and it can be heated to extreme temperatures before it will melt
The property of a metal which allows little bending or deformation without shattering. It is apt to break or crack without change of shape.
Brittleness
Most aircraft bolts are fabricated from what material?
Cadmium or zinc plated corrosion resistant steel, and unplated corrosion resistant steel, anodized aluminum
What material are control cables made from?
Carbon and stainless steel
What class are almost all aircraft bolts manufactured at?
Class 3
The property of a metal that enables a metal to carry heat of electricity.
Conductivity
What is the most widely used linkage in flight control systems?
Control cables
The weight of a unit volume of a material. In aircraft work, the specified weight of a material per cubic inch. This is an important consideration when choosing a material to be used in the design of a part in order to maintain the proper weight and balance of the aircraft.
Density
The property of metal which permits it to be permanently drawn, bent, or twisted into various shapes without breaking. This property is essential for metals used in making wire and tubing.
Ductility
The property that enables a metal to return to its original size and shape when the force which causes the change of shape is removed.
Elasticity
The ability of a metal to become liquid by the application of heat
Fusibility
The ability of a material to resist abrasion, penetration, cutting action, or permanent distortion.
Hardness
What 2 units of measure are used in torque value?
Inch pounds and foot pounds
Why is Teflon such a good material for use on seals?
It does not deteriorate with age, and can tolerate extreme temperatures
What does MS mean
Military Standard
What are the threads per inch of fine threads?
NF is 12 UNF is 14
What does NAS mean
National Aerospace Standard
What does NAF mean
Naval Aircraft Factory
What are 3 defining shapes of packings or seals?
O, U, V
What is a packing?
Packings are made of rubber. They are generally used as "running seals"
What are two general categories of aircraft nuts?
Self locking and non selflocking
What does SAE mean
Society of Automotive Engineers
What are the two main categories of rivets?
Solid shank and blind
One of the most important properties of metal. The ability of the material to resist deformation and to resist stress without breaking.
Strength
Why are different metals needed for the repair of aircraft?
Strength, Weight, Durability, and resistance to deterioration of specific structures or parts
Why is the selection of the right metal/materials so important in aircraft maintenance?
The use of inferior materials can result in the loss of life and equipment
This refers to contraction and expansion that are reactions produced in metals as the results of heating or cooling.
Thermal Expansion
What is the direction safety wire is supposed to pull and why?
Tightening to prevent loosening
What table is available for use in finding general torque settings for nuts, screws, and bolts?
Torque Table
What tool is used for torqueing hardware?
Torque wrench
A property of metal that will withstand tearing or shearing and may be stretched or otherwise deformed without breaking.
Toughness
What are cable designation based on?
based on the number of strands and the number of wires in each strand. Example 7x7
What are 2 types of threads?
fine and coarse
What is a gasket?
gaskets are used as static (stationary) seals between two flat surfaces. Common gasket materials are asbestos, copper, cork, and rubber
what does MS 4-28 mean?
indicates that a 1/4inch (4/16inch) diameter bolt has 28 threads in 1 inch of its threaded length
what does 7x19 in a cable mean?
the cable is made up of 7 strands of 19 wires each
What are wipers used for?
used to clean and lubricate the exposed portions of piston shafts.
