Sheet Metal Structural Repair Flashcards

What is the allowable shop head height for a properly driven solid shank rivet?

Answer: 0.5D to 0.7D (50% to 70% of rivet diameter)

A properly driven rivet shop head should be 0.5D to 0.7D in height and 1.4D to 1.5D in diameter.

When a repair requires replacing rivets with the next larger size, what must be verified before proceeding?

Answer: The larger hole does not reduce the sheet's net section below allowable limits

Drilling to the next larger size removes more material, and the remaining net section must be checked to ensure structural adequacy.

What is the primary advantage of a scab (overlay) patch compared to a flush insert patch?

Answer: It is easier and faster to fabricate and install

A scab patch is quicker to make and install because it does not require cutting a precise insert to fill the damaged area.

Before drilling rivet holes in a repair patch, which layout step is performed first?

Answer: Marking the rivet centerline and edge distances with a scriber or pencil

Rivet centerlines and edge distances must be marked accurately before drilling to ensure proper spacing and edge clearance.

Which aluminum alloy is most commonly used for aircraft structural skin repairs due to its high strength-to-weight ratio?

Answer: 2024-T3

2024-T3 is the standard aircraft skin material, offering high strength and good fatigue resistance in thin sheet form.

What condition requires immediate rejection of a rivet during installation?

Answer: The shop head cracks or splits during driving

A cracked or split shop head indicates an improperly driven rivet that has failed and must be drilled out and replaced.

What is the function of a bucking bar during solid rivet installation?

Answer: To support and form the shop head on the back side of the rivet

The bucking bar is held against the rivet tail on the blind side; the hammer drives the manufactured head while the bar forms the shop head.