Airframe Mechanic Certification Sheet Metal Structures 2

Question 1

What is the minimum edge distance for a rivet hole measured from the center of the hole to the edge of the sheet?

Accepted Answer

1.5 times the rivet diameter

Answer

The minimum edge distance is 1.5 times the rivet diameter to prevent sheet tearing and ensure structural integrity.

Question 2

When forming a bend in sheet metal, the bend allowance refers to:

Accepted Answer

The arc length of material consumed in the curved portion of the bend

Answer

Bend allowance is the arc length of material that forms the curved section of the bend, used to calculate flat pattern dimensions.

Question 3

Which type of corrosion appears as white or gray powdery deposits on aluminum sheet metal?

Accepted Answer

Surface (uniform) corrosion

Answer

Surface or uniform corrosion on aluminum produces a white or gray powdery aluminum oxide deposit on the surface.

Question 4

A 'joggle' in aircraft sheet metal is used to:

Accepted Answer

Allow one sheet to overlap another while maintaining a flush surface

Answer

A joggle is an offset bend that allows overlapping sheets to remain flush with each other and the surrounding structure.

Question 5

What is the purpose of using a dimpling operation instead of countersinking on thin sheet metal?

Accepted Answer

Thin sheet does not have enough material depth for a full countersink without knife-edge

Answer

On thin sheets, countersinking can leave a knife-edge around the hole, so dimpling displaces material rather than removing it.

Airframe Mechanic Certification Practice Test