ACS Non-Destructive Testing (NDT) Methods

Question 1

Which NDT method is most effective for detecting surface and near-surface cracks in ferromagnetic aircraft components?

Accepted Answer

Magnetic particle inspection

Answer

Magnetic particle inspection (MPI) is specifically designed for ferromagnetic materials and can reveal both surface and subsurface discontinuities by applying a magnetic field and iron particles.

Question 2

What is the primary purpose of the developer in dye penetrant inspection?

Accepted Answer

To draw the trapped penetrant back to the surface to form an indication

Answer

The developer acts as a blotter, drawing the entrapped penetrant out of discontinuities to form a visible indication on the surface.

Question 3

In dye penetrant inspection, what is the correct sequence of steps?

Accepted Answer

Clean → Apply penetrant → Remove excess → Apply developer → Inspect

Answer

The correct sequence is: pre-clean the surface, apply penetrant and allow dwell time, remove excess penetrant, apply developer, then inspect under appropriate lighting.

Question 4

Which type of visual inspection tool is used to inspect the interior of an engine cylinder without disassembly?

Accepted Answer

Borescope

Answer

A borescope is an optical instrument with a rigid or flexible tube used to inspect the interior of inaccessible areas such as engine cylinders without requiring disassembly.

Question 5

What is the minimum dwell time typically specified for dye penetrant inspection of standard discontinuities in aluminum alloy parts?

Accepted Answer

5 to 30 minutes

Answer

For most aluminum alloy parts, penetrant dwell times typically range from 5 to 30 minutes to allow adequate capillary action into discontinuities, as specified by the applicable process specification.

(ACS) Airman Certification Standard Certified Mechanic Practice Test

(ACS) Airman Certification Standard Certified Mechanic Practice Test

ACS Non-Destructive Testing (NDT) Methods