AMT Corrosion Control and Treatment Questions and Answers

Question 1

An aircraft operating in a coastal, high-humidity environment is undergoing a detailed inspection.
The technician notices worm-like tracks and bubbling under the paint on an aluminum skin panel.
What type of corrosion is most likely present?

Accepted Answer

Filiform corrosion

Answer

Intergranular corrosion

Answer

Fretting corrosion

Answer

Galvanic corrosion

Question 2

A technician is treating an area of surface corrosion on an aluminum alloy fuselage. After mechanically removing the corrosion products, what is the primary purpose of applying a chemical conversion coating like Alodine before priming?

Accepted Answer

To form a passive oxide film that inhibits further corrosion and promotes paint adhesion.

Answer

To increase the surface hardness and wear resistance.

Answer

To provide a sacrificial layer that is more anodic than the aluminum.

Answer

To restore the material lost to corrosion.

Question 3

During an inspection of a high-time aircraft's wing structure, a technician discovers evidence of corrosion that appears to be attacking the metal along the grain boundaries. This has led to a lifting or flaking of the metal surface. This describes which form of corrosion?

Accepted Answer

Exfoliation corrosion

Answer

Pitting corrosion

Answer

Uniform surface corrosion

Answer

Crevice corrosion

Question 4

Fretting corrosion is most likely to be found in which of the following locations on an aircraft?

Accepted Answer

Between two aluminum sheets in a lap joint under a loose rivet.

Answer

In the bottom of the bilge area where water may collect.

Answer

On a magnesium skin panel with chipped paint.

Answer

On a stainless steel firewall.

Question 5

When inspecting a piano-type hinge on a control surface, a technician finds white powdery deposits and notices the hinge is stiff. What is the most appropriate initial maintenance action?

Accepted Answer

Clean the hinge thoroughly, remove the corrosion, and lubricate before re-evaluating.

Answer

Replace the entire hinge assembly immediately.

Answer

Apply a water-displacing lubricant and cycle the hinge until it moves freely.

Answer

Paint over the affected area to seal out moisture.

Question 6

Which of the following is an essential requirement for galvanic corrosion to occur?

Accepted Answer

Two dissimilar metals in contact and the presence of an electrolyte.

Answer

The presence of a high-tensile stress on one of the metals.

Answer

An acidic environment with a pH below 5.0.

Answer

Repetitive microscopic movement between two surfaces.

An aircraft operating in a coastal, high-humidity environment is undergoing a detailed inspection.The technician notices worm-like tracks and bubbling under the paint on an aluminum skin panel.What type of corrosion is most likely present?

An aircraft operating in a coastal, high-humidity environment is undergoing a detailed inspection.
The technician notices worm-like tracks and bubbling under the paint on an aluminum skin panel.
What type of corrosion is most likely present?