FREE A&P Sheet Metal Structural Repair Questions and Answers

Question 1

During a visual inspection of a fuselage, a technician notices fine black streaks trailing back from several rivet heads. This phenomenon, commonly referred to as 'smoking,' is a primary indicator of which of the following conditions?

Accepted Answer

Fretting corrosion caused by slight movement of a loose rivet.

Answer

The term 'smoking rivets' describes the fine black powder (aluminum oxide) that is worked out from under the rivet head due to slight, repeated movement under load or vibration. This movement is a form of fretting, which causes microscopic wear on the rivet and the surrounding skin, indicating the rivet is loose and its clamping force is compromised.

Question 2

A maintenance technician discovers a small crack propagating from a rivet hole in an aluminum alloy skin panel. According to standard repair practices, what is the immediate and primary action to be taken to prevent further propagation before a permanent repair is made?

Accepted Answer

Stop-drill the end of the crack.

Answer

Stop-drilling is the correct immediate action to halt the growth of a crack. By drilling a small hole at the very tip of the crack, the sharp stress concentration at the crack's end is redistributed around the larger radius of the hole, which effectively stops or significantly slows its propagation. This allows for a permanent repair, such as a patch, to be performed later.

Question 3

Which of the following solid shank rivets, known as an 'icebox' rivet, must be heat-treated and then stored at low temperatures until it is driven to prevent age hardening?

Accepted Answer

2024-T4 (DD)

Answer

Rivets made from 2024 aluminum alloy (identified by two raised dashes or the code 'DD') are solution-heat-treated to soften them for driving. They begin to age-harden rapidly at room temperature, so they must be stored in a freezer ('icebox') and driven within a short period after removal (typically 10-20 minutes) to remain malleable.

Question 4

An A&P technician is laying out a repair pattern on a piece of 2024-T3 aluminum alloy sheet. To avoid creating potential points of failure, which of the following is the most appropriate tool for marking cut lines that will remain on the finished part?

Accepted Answer

A graphite pencil or a permanent marker.

Answer

Using a scribe, awl, or any tool that scratches the surface of heat-treated aluminum alloys is prohibited because the scratch creates a stress riser. A stress riser is a microscopic groove that concentrates stress, potentially leading to the formation of a crack under load. A soft graphite pencil or a felt-tipped marker should be used for layout lines as they do not damage the material's surface.

Question 5

In a sheet metal repair, what is the term for the distance between the centers of adjacent rivets in the same row?

Accepted Answer

Rivet Pitch

Answer

Rivet pitch is defined as the distance measured along the centerline of a single row of rivets, between the centers of adjacent rivets. Transverse pitch (or rivet gauge) is the distance between rows of rivets, and edge distance is the distance from the center of a rivet to the edge of the sheet metal.

A&P - Certified Airframe and Powerplant Mechanics Practice Test

A&P - Certified Airframe and Powerplant Mechanics Practice Test

FREE A&P Sheet Metal Structural Repair Questions and Answers