CORROSION
What corrosion involves only the metal surface, and appears over a wide area?
Uniform surface corrosion
Rationale: General surface corrosion (also referred to as uniform etch or uniform attack corrosion) is the most common form of corrosion. Surface corrosion appears as a general roughening, etching, or pitting of the surface of the metal, frequently accompanied by a powdery deposit of corrosion products.
Why is it critical for an AMT to verify the revision block before starting work on a component?
It confirms the drawing is current and accurate for work
Rationale: It makes sure they are using the current approved drawing for accurate work.
Which tool is used to create or repair threads inside a hole?
Tap
Rationale: Taps are designed to cut or repair internal threads.
Which part number designation identifies a universal head rivet?
AN470
Rationale: AN470 identifies a universal head shape rivet.
Which material is known to damage anodized aluminum surfaces?
Steel wool
Rationale: Steel wool is too abrasive and can scratch the protective anodized layer on aluminum. It can also leave behind particles that may rust, compromising both appearance and corrosion resistance.
What is the primary purpose of aircraft paint?
To protect the aircraft from corrosion.
Rationale: Paint acts as a protective layer, preventing corrosion
What document provides safety and handling information for chemicals used in corrosion control?
Safety Data Sheet (SDS)
Rationale: The SDS outlines hazards, handling procedures, PPE requirements, and emergency measures for chemicals.
This is the allowable plus or minus variation from the dimension given on the drawing?
Tolerance
What type of corrosion is "smoking rivets" associated with?
Fretting corrosion
Rationale: The most common example of fretting corrosion is the smoking rivet found on engine cowling and wing skins.
What does a Half Section drawing help an AMT see?
Both the inside and outside of a symmetrical part
Rationale: A Half Section drawing is used for symmetrical parts and shows both the inside and outside. This helps an AMT understand the full structure without needing multiple views.
Which measuring tool is best suited for checking the diameter of a small aircraft shaft?
Caliper
Rationale: Calipers (vernier/digital) provide precise diameter measurements.
Aircraft bolt diameters are measured in?
1/16
Rationale: Aircraft bolt diameters are measured in 16ths.
Why is it important for an AMT to understand the properties of non-ferrous metals like, aluminum and titanium during aircraft inspections and repairs?
These metals require unique handling, repair methods, and prevent corrosion while maintaining aircraft performance.
Rationale: Knowledge of non-ferrous metals’ corrosion resistance, weight, and repair considerations ensures proper maintenance practices and safety.
A primary reason why ordinary or otherwise non-approved cleaning compounds should not be used when washing aircraft is because their use can result in:
Hydrogen embrittlement in metal structures
Rationale: Some nonapproved commercial cleaning compounds can cause a chemical reaction with some of the metals used in aircraft structure. This reaction releases hydrogen gas that can be absorbed into the metal and cause hydrogen.
Which property does hardness testing evaluate in a metal?
The metal’s resistance to being dented
Rationale: Hardness testing measures resistance to denting and deformation.
In what type of electrical diagram are images of components used instead of conventional electrical symbols?
Pictorial Diagram
Which type of corrosion occurs when two dissimilar metals are in contact with each other in the presence of an electrolyte?
Galvanic corrosion
Rationale: Galvanic corrosion occurs when dissimilar metals touch in moisture.
What type of line is used to show exposed surfaces?
Sectioning Line
Rationale: Sectioning lines (also called crosshatch lines) are used in drawings to indicate exposed surfaces in a sectional view, showing where material has been “Cut through.”
What tool is used to mark precise, fine lines on metal surfaces before cutting or drilling?
Scriber
Rationale: Scribers are pointed tools used to create fine, permanent lines on metal surfaces to guide accurate cutting or drilling.
Aircraft solid rivet diameters are measured in
1/32
Rationale: Rivet diameters are measured in 32nds
Which heat-treated aluminum alloy is most commonly used for aircraft skin?
2024
Rationale: 2024 is commonly used for stringers, bulkheads, skin, rivets, and extruded sections.
Which two types of paint are most commonly used on aircraft?
Polyurethane and epoxy
Rationale: These types are most commonly used in aviation due to their durability, resistance to chemicals, and ability to protect against corrosion and environmental stress.
While working on an aircraft windshield replacement, you find light scratches on the new acrylic transparent panel. What is the best course of action before installation?
Polish out the scratches using an approved plastic polish to restore visibility and prevent crack propagation.
Rationale: Approved polishing restores optical clarity, maintains safety, and prevents stress crack propagation in acrylic windows.
What type of diagram shows the wire size required for a particular installation?
A Wiring Diagram
What is the main difference between aluminum oxide and iron oxide?
Aluminum oxide forms a stable protective layer, while iron oxide flakes away, exposing more metal.
Rationale: Aluminum oxide creates a stable layer preventing further corrosion, while iron oxide flakes off, allowing corrosion to continue.
What is the function of phantom lines in aircraft drawings?
They show where a part might move or where a missing part would.
Rationale: Phantom lines (long dash, short dash, short dash) indicate alternate positions of moving parts or related parts not shown.
When removing a stuck fastener or trimming a metal edge, which tool is most appropriate to use?
Chisel
Rationale: A chisel is the proper tool to cut, shear, or chip away metal. It can be used to remove a stuck fastener head or trim excess metal edges when precision cutting tools are not appropriate.
How would you identify an aluminum alloy bolt?
A double dash on the head
Rationale: A double dash on the head of a bolt indicates an aluminum alloy bolt.
The letter T indicates a metal is in what condition?
Heat treated
Rationale: In aircraft metals, the letter “T” indicates the metal has undergone specific heat treatments (like quenching, cooling, and aging) to achieve desired mechanical strength and stability.
During a post-paint inspection, an AMT notices a cloudy, milky finish on the surface of a newly painted aircraft panel. What is the most likely cause of this defect?
The humidity in the paint booth was too high during application.
Rationale: High humidity can cause blushing, where moisture gets trapped in the paint as it flashes off, creating a cloudy appearance
What grade aluminum alloy is the “field rivet”?
AD- 2117
Rationale: The 2117-T rivet, known as the field rivet, is used more than any other for riveting aluminum alloy structures.
A drawing in which the subassemblies or parts are shown as brought together on the aircraft is called a what?
Installation Drawing.
What form of corrosion appears as “worm-like” lines under paint due to trapped moisture?
Filiform corrosion
Rationale: Filiform corrosion shows as lines under paint.
What is the primary purpose of a nomogram in aviation maintenance?
Calculate approximate values without a calculator
Rationale: Nomograms are used for quick calculations (weight & balance, conversions) in the field.
Which tool is used to measure the clearance between a surface plate and a relatively narrow surface being checked for flatness?
Thickness gauge
Rationale: A thickness gauge is used to measure gaps/clearances/distances between surfaces.
Which type of aircraft cable is constructed of seven strands and 19 wires in each strand
7 x 19 cable
Rationale: The 7 × 19 cable is made up of seven strands of 19 wires each. Six of these strands are laid around the center strand. This cable is extra flexible and is used in primary control systems and in other places where operation over pulleys is frequent.
What is the purpose of tempering after hardening steel during heat treatment?
To reduce brittleness and improve toughness.
Rationale: Tempering is a post-hardening process used to relieve internal stresses, reduce brittleness, and increase toughness while still maintaining most of the hardness.
Which chemical treatment is specifically noted as a milder option for treating aluminum parts with complex shapes?
Sodium dichromate solution
Rationale: Sodium dichromate solution is recognized as a milder and safer chemical treatment for aluminum parts, especially those with complex geometries. It effectively treats corrosion while minimizing damage or aggressive chemical action, making it suitable for delicate or intricate components.
Why would a topcoat begin to peel if it is applied several days after an epoxy primer has been applied to a composite panel without additional surface preparation?
The primer cured fully and needed sanding for proper bonding.
Rationale: After full cure, epoxy primer loses chemical bonding ability. Re-sanding is required to create a surface the topcoat can adhere to mechanically.
In a sectional view drawing, what sections illustrate particular parts of an object?
Removed Sections.